History

Consumer Confidence Report Translation

2025 For the year 2024

Message from the Director of Utilities

We are pleased topresent this Consumer Confidence Report, which contains vital information about the quality of your drinking waterand the standards we follow, as set by the UnitedStates Environmental Protection Agency (USEPA) and the State Water Resources Control Board (SWRCB).

At the Utilities Department (UD), ensuring the safety andreliability of your wateris our highest priority. Our highly trainedWater Operations staff conduct daily sampling, with all samples sent to independentlaboratories for thorough testing. In 2024, weconducted 5,120 water quality teststo monitor water quality and deliver the best possible blend of water directly to your tap.

This report summarizes data from 2024, including where yourwater comes from, how it is treated, and how it compares to regulatory standards. I’m proud to share that our water met or exceededall USEPA and State health standards throughout the year. Ourdedicated team ensured that no primary MaximumContaminant Levels (MCLs) were exceeded.

Thank you for trusting us to provide safe, high-qualitydrinking water every day.

Tom Moody

Director of Utilities

(951)736-2477

www.CoronaCA.gov

Corona’s Water Sources

In 2024, Corona residents and businesses usedapproximately 9.7 billion gallons of drinking water. Corona’s water supply comes from differentsources: groundwater wells owned and operatedby the City of Corona provided 42.3%,55.8% came through Lake Mathews from the Colorado River, and 1.9% was from the State Water Project’sCalifornia Aqueduct.

Water Treatment Processes

The surface water from the Colorado River requirestreatment to become drinking water. The treatment process is accomplished in the City of Corona’s two surface water treatment facilities:Sierra Del Oro and Lester. Thesefacilities incorporate the use of coagulants, which bind small particlestogether to form larger particles that can be easily removed throughmultimedia filtration. After filtration, the water is treated with sodiumhypochlorite to kill or inactivate harmfulorganisms. This part of the process is called disinfection.

Throughindependent laboratory testing, 100% of the samples taken in2024were free of harmful organisms.

Most of the groundwater pumped in Corona was sent through a state-of-the-art reverse osmosis membrane treatment facility,the Temescal Desalter. This facilityprovides removal of nitrates, per-fluorinated compounds, 1,2,3-Trichloropropane (1,2,3-TCP), perchlorates, and suspended and dissolvedsolids. The UD adds an ammonium hydroxide solution to thedisinfected water, which in conjunction withsodium hypochlorite forms a compoundcalled chloramines. This chemicalacts as a disinfectant in the distribution system andremains active for a longer period of time than sodium hypochlorite alone. It also helps reduce the formation ofdisinfection byproducts that could be harmfulto our health. Disinfection byproductsare formed when some disinfectants like chlorine react with naturally occurring organic matter in the water.

Blending

The UD has five blending facilities that blend treatedgroundwater sources with raw groundwater sources and treated surface water todeliver safe, reliabledrinking water to your tap. You will notice in the tables of detected contaminants that thegroundwater exceeded the primarystandard for fluoride, nitrate and perchlorate. The UD is required by law to report the range of all raw groundwater samples monitored,as well as the average concentration deliveredto your tap. The averages of what you receiveat your tap are much lower because the UD treats and blends water from several sources to improve water quality.The blending stations are continuously monitored and routinely sampled toensure that the water delivered to your tap meets all health standards with a safety margin of no less than 10%. Please refer to the “Treated AverageSystem Water” column in the tablesat the end of the report for a more accuraterepresentation of system water quality.

For more information aboutfluoridation, oral health, and current issuesvisit: https://www.waterboards.ca.gov/drinking_water/certlic/ drinkingwater/Fluoridation.html.

Reclaimed Water

To improvewater supply reliability for the City, the UD developed andbegan building our reclaimed water system in2006. Utilizing reclaimed water to help meet water demands for the City reduces the impact ofimported water supply shortages and costs. The reclaimed water system uses highly treated wastewater from our sewer treatment facilities and distributes it throughout the City. The reclaimed water systemis separate from the drinkingwater system. Reclaimed water pipes, sprinkler caps, and signage are painted purple toeasily identify them as part of thereclaimed water system. Reclaimed water is used primarily on landscaping at parks, schools, parkway areas, and a few commercialbuildings. By re-using water we save potable water for our homes andbusinesses. A rebate incentive is offered forbusinesses that convert their landscapeirrigation and/or process operation water use to reclaimed water. Save water and get fundingassistance to cover the conversion.Contact the Water Resources Team at (951) 736-2234 or by e-mail at WaterRebates@CoronaCA.gov to see if your businessis eligible.

The City of Corona’s reclaimed water system infrastructure consists ofapproximately 62 miles of pipeline, threestorage tanks, and six pump stations.

Of the reclaimed water produced, 1.19 billion gallonswent into the reclaimedwater distribution system for customer use. We currently have 434 connectionsand arecontinually adding new sites.

Water Conservation

Our changing climate requires Californians to movebeyond temporary emergency droughtmeasures and adopt permanent changes to use water more wisely and prepare for more frequent and persistent periodsoflimited water supply. Conservation and efficiency also reduce the energy needed to pump, transport,treat and deliver water. Your smallchanges make a big impact. We askthat everyone be efficient in their waterusage, by requiring all residents and businesses in the UD’s service area to follow the water use guidelineson the next page.

Water Use Guidelines – Stage 2

•    No watering between10 a.m. and 8 p.m.

•    Odd-numberedaddresses can water on Saturday, Monday, and Wednesday only.

•    Even-numberedaddresses can water on Sunday, Tuesday, and Thursday only.

•    Wateringon Fridays is prohibited. Since government institutions are not open on weekends,they may water three days per week of the agency’s choosing.

•    Limitsprinkler times to help conserve water.

•    Leaksand broken sprinklers must be fixed in a timely manner.

•    Wateringduring and within 48 hours after rainfall measuring ½” or more is prohibited.

•     Drip irrigation, which waters ingallons per hour, can water for a maximum of 90 minutes per day, provided thereis no runoff.

•    Watercannot be allowed to run off the property.

•     All swimming pools, spas, ponds, andfountains shall be equipped with re-circulating pumps.

•    Washinghard surfaces is prohibited.

•    Vehiclescan only be washed using a bucket and a hose with an automatic shut-off nozzle.

•    InCorona, food establishments are prohibited from providing drinking water topatrons unless requested.

•    Streettrees must be kept alive.

Rebates for WaterSaving Appliances and Devices

Improve the water use efficiency at your home orbusiness by upgrading your appliances and fixtures to water efficient models. The UD offers rebates for the followingwater saving appliances, devices, and fixtures:

•        High Efficiency Clothes Washer

•        Premium High Efficiency Toilets

•        Weather Based Irrigation Controllers

•        Soil Moisture Sensors

•        Rotating Nozzles

•        Rain Barrels

•        Turf Replacement

The UD also offers other residential rebates for apool cover and a recirculating hot waterdevice. For more information on these and other water efficiency rebatesavailable to Coronaresidents, please contact theWater Resources Team at (951) 736-2234 or e-mailWaterRebates@CoronaCA.gov.

Water Efficiency Rebates for Businesses

The UD offers numerousrebates just for businesses to help them improvewater efficiency. Available rebates for devices and fixtures include:

•    Premium High Efficiency Toilets

•    Ultra-Low and Zero Water Urinals

•    Plumbing Flow Control Valves

•    Air Cooled Ice Machines

•    Connectionless Food Steamers

•    Dry Vacuum Pump

•    Laminar Flow Restrictions

•    Conductivity and pH Controllers for Cooling Towers

•    Weather-Based Irrigation Controllers (WBICs)

•    Soil Moisture Sensor Systems

•    Rotating Nozzles for Pop-Up Spray Heads

•    Large Rotary Nozzles

•    In-Stem Flow Regulators

•    Turf Replacement

•    Reclaimed Water Conversion Program (where available)

For more information onthese and other water efficiency rebates availableto Corona businesses, contact the WaterResources Team at (951) 736-2234or e-mail WaterRebates@CoronaCA.gov.

Corona Recycles Team In Action!

The Corona Recyclesteam has been hard at work over the past few years! In 2024, the Corona Recycles team continued implementing Senate Bill (SB) 1383,the State’s most ambitious recycling law, and met the following milestonestowards compliance:

•    Implemented required SB 1383 services to all residents and businesses

•    Assisted all Tier 1 Edible Food Generators with getting in compliance withEdible Food Recovery Requirements

•    Conducted education & outreach activities to provide residents andbusinesses with information on SB 1383 compliance

Additionally, the Corona Recycles team providedresidents with countertop kitchen caddies that can be utilized for separatingfood scraps from everyday trash in the kitchen. Reusable grocery totes were alsooffered to residents to aid in the reduction of the use of plastic bags thatend up in landfills.

In 2025, the Corona Recycles team will continuetheir education and outreach efforts for SB 1383 and expand their Edible FoodRecovery Program, aimed at reaching the State’s goal of recovering at least 20%of edible food that is currently being disposed of and donating it to those inneed. The team will also be hosting additional events for residents, includinga Community Clean-Up event where residents can dispose of any bulky items theymay have at home as well as bring old documents and paper for shredding anddisposal. We will continue to strive to make the City of Corona a more environmentallysustainable community.

Questions about any of our programs? Visit ourwebpage at www. CoronaCA.gov/Recycle where you will findeducational resources on SB 1383, as well as other information on our variousprograms, including instructions on how to request a countertop kitchen caddyor reusable grocery toteson theResidential Waste & RecyclingGuidelines tab. You canalso reach out to us by email at CoronaRecycles@CoronaCA.gov.

From Your Drain to the Environment – Keep It Clean

While water reclamation treatment removes mostpollutants, even trace amounts of some substances may be harmful to theenvironment. The best solution is to prevent pollution from going down thedrain in the first place.

Dispose of unwantedmedicine properly… No Drugs Down the Drain!

For years, unwanted medicine was flushed down thedrain to protect children and pets from accessing it, and to ensure againstillegal recovery of controlled substances. Today, there are better options.Please visit the U.S. Food and Drug Administration website for more informationon how to dispose of unused medicine: https://www.fda.gov/forconsumers/ consumerupdates/ucm101653.htm.

Keep drains free of FOG – Fats, Oils,and Grease

When washed down the drain, cooking fats, oils, andgrease, aka “FOG,” harden andblock sewer lines. This causes raw sewage to back up into yourhome or onto neighborhood streets and storm drains, which drain to rivers and the ocean. Overflowscan be costly and pose health and environmental hazards. Keep your sewer linesFOG free by allowing it to cool then scraping cooking fats into the garbage or intoa container, such as an old metal coffee can or food scrap recycling bin –never down the drain!

Sanitary wipes are another item that often causesblockages in the City’s sewer lines. They should be kept away from drains andshould not be flushed down the toilet, even if they are labeled as “flushable”.

General Water QualityInformation

Drinkingwater sources (both tap and bottled water) include rivers, lakes, streams,ponds, reservoirs, springs, and wells. As water travels over thesurface of the land or through the ground, it dissolves naturally-occurring minerals and,in some cases, radioactive material, and can pick up substances resulting from the presenceof animals or from human activity.

Contaminants that may be present insource water include:

•     Microbial contaminants, such as viruses and bacteriathat may come from sewage treatment plants, septic systems, agriculturallivestock operations, and wildlife.

•     Inorganic contaminants, such as salts and metals, thatcan be naturally- occurring or result from urban stormwater runoff, industrialor domestic wastewater discharges, oil and gas production, mining or farming.

•     Pesticides and herbicides that may come from a varietyof sources such as agriculture, urban stormwater runoff, and residential uses.

•     Organic chemical contaminants, including synthetic andvolatile that are byproducts of industrial processes and petroleum production,and can also come from gas stations, urban storm water runoff, agriculturalapplication, and septic systems.

•     Radioactive contaminants that can benaturally-occurring or be the result of oil and gas production and miningactivities.

In order to ensure that tap water is safe to drink, the USEPA and theState Water Resources Control Board(SWRCB) prescribe regulations that limit the amount of certain contaminants in water provided by public watersystems. U.S. Food and Drug Administration regulations and Californialaw alsoestablish limits for contaminants in bottled water thatprovide the same protectionfor public health.

Drinking water, including bottled water, mayreasonably be expected to contain atleast small amounts of some contaminants. The presence of contaminants does not necessarily indicate thatwater poses a health risk. Moreinformation about contaminants and potential health effects can be obtained by calling the U.S. EPA’s Safe DrinkingWater Hotline (1-800 426-4791).

Some people may be more vulnerable to contaminants in drinkingwater than the general population.Immuno-compromised persons such aspersons with cancer undergoing chemotherapy, persons who haveundergone organ transplants, people with HIV/AIDS or other immune system disorders,some elderly, and infants can be particularly at risk. These people should seek advice from their healthcare providers about drinking water.USEPA/Centers for Disease Control (CDC) guidelines on appropriate means to lessen the risk of infection by Cryptosporidiumand other microbial contaminants areavailable from the Safe Drinking Water Hotline (1-800-426-4791).

Nitrate

Nitrate in drinking water atlevels above 10 mg/L as nitrogen is a health risk especially for infantsof less than six monthsof age because it can interferewith the capacity of the infant’s bloodto carry oxygen,resulting in a serious illness;symptoms include shortnessof breath and blueness of theskin. Nitrate levels above 10 mg/L may alsoaffect the ability of the blood tocarry oxygen in other individuals, such as pregnant women and those with certain specificenzyme deficiencies. If you are caring for an infant,or you are pregnant, you shouldask advice from your health care provider.

Arsenic

While yourdrinking water meets the federaland statestandard for arsenic, it does containlow levels of arsenic. The arsenic standard balances the currentunderstanding of arsenic’s possible health effects against the costs of removingarsenic from drinking water. The U.S. EnvironmentalProtection Agency continues to research thehealth effects of low levels of arsenic, which is a mineral known to cause cancerin humans at high concentrations and islinked to other health effects such as skin damage and circulatory problems.

Source Water Assessment

In accordance with the Federal Safe Drinking WaterAct (SDWA), the SWRCB Division of Drinking Water and Environmental Managementdeveloped a program, called the Drinking Water Source Assessment and Protection(DWSAP) Program, to assess the vulnerability of drinking water sources tocontamination. Assessments of the drinking water sources for the City of Coronawere completed in February 2012. The assessment concluded that the City ofCorona’s sources are considered most vulnerable to the following activities notassociated with any detected contaminants in the water supply: automobile – gasstations, chemical/petroleum pipelines, chemical/ petroleum processing/storage,dry cleaners, historic gas stations, machine shops, metalplating/finishing/fabricating, mining sand/gravel, NPDES/WDR permitteddischarges, plastics/synthetics producers, septic systems – low density [<1/acre],sewer collection systems, underground storage tanks – confirmed leaking tanks,utility stations – maintenance areas, and wastewater treatment plants. A copyof the completed assessments are available through the City of Corona’s City Clerk’soffice at 400 S. Vicentia, Corona, CA 92882, or by using the online PublicRecords Request form at https://www.coronaca.gov/departments/city-clerk/public-records-request.

Lead and Copper Rule Monitoring

Parameter

Units

State MCL

PHG

State DLR

Date Sampled

90th Percentile

No. Sites  Sampled

No. Sites  Exceeding AL

Lead

ppb

AL=15

0.2

5

2023

5

53

3

Copper

ppm

AL=1.3

0.3

0.05

2023

0.17

53

0

The Lead andCopper Rule (LCR) was developed to protect public health by minimizing lead and copper levels in drinking water. The LCRestablished an action level of 15 parts per billion (ppb) for lead and 1.3 parts per million(ppm) for copper based on the 90th percentile level of tap water samplescollected. Lead and copper are sampled on amandated three-year testingcycle with samplingconducted at the customer’s tap.

AL              Action Levels

DLR            Detection Limitsfor purposes of Reporting

MCL           Maximum Contaminant Level

PHG           Public HealthGoal

ppb            Parts per billion or micrograms per liter (μg/L)

ppm           Parts per million or milligrams per liter (mg/L)

Lead

The City ofCorona Utilities Department recently conducted a digital inventory of all waterservice lines, which is the pipe that connects your home, building, or otherstructure to the water main. The purpose of the inventory is to identify thematerial of these service lines and fittings, including the customer-owned sideof the water service line.

A select numberof pipes that connect homes, buildings, or other structures to the water mainwas identified as an unknown material. Starting Fall 2025, the City of Coronawill begin efforts to identify these unknown service line materials as part ofa system-wide inventory update. Inventory can be found at www.CoronaCA.gov/lead.

Lead can causeserious health effects in people of all ages, especially pregnant people, infants(both formula-fed and breastfed), and young children. Lead in drinking water isprimarily from materials and parts used in service lines and in home plumbing.The Utilities Department is responsible for providing high quality drinkingwater and removing lead pipes but cannot control the variety of materials usedin the plumbing in your home. Because lead levels may vary over time, leadexposure is possible even when your tap sampling results do not detect lead atone point in time. You can help protect yourself and your family by identifyingand removing lead materials within your home plumbing and taking steps toreduce your family’s risk. Using a filter, certified by an American NationalStandards Institute accredited certifier to reduce lead, is effective inreducing lead exposures. Follow the instructions provided with the filter toensure the filter is used properly. Use only cold water for drinking, cooking,and making baby formula. Boiling water does not remove lead from water. Beforeusing tap water for drinking, cooking, or making baby formula, flush your pipesfor several minutes. You can do this by running your tap, taking a shower,doing laundry or a load of dishes. If you have a lead service line orgalvanized requiring replacement service line, you may need to flush your pipesfor a longer period. If you are concerned about lead in your water and wish tohave your water tested, contact the Utilities Department at 951-736-2276.Information on lead in drinking water, testing methods, and steps you can taketo minimize exposure is available at https://www.epa.gov/ safewater/lead.

Primary Standards – Mandatory Health-Related Standards

CLARITY

PARAMETER

UNITS

STATE MCL [MRDL]

PHG (MCLG) [MRDLG]

STATE DLR/ CCRDL(RL)

RANGE AVERAGE

WATER SOURCE

MAJOR SOURCES IN DRINKING WATER

Combined Filter Effluent Turbidity

%

95(a)

NA

–

% < 0.3

100%

Metropolitan Water  District Henry J. Mills Water Treatment Plant

Soil runoff

NTU

TT 0.3

Highest

0.08

Combined Filter Effluent Turbidity

%

95(a)

NA

–

% < 0.3

100%

City of Corona,  Lester & Sierra  Del Oro Water Treatment  Facilities

Soil runoff

NTU

TT 0.3

Highest

0.05

MICROBIOLOGICAL CONTAMINANTS

PARAMETER

UNITS

STATE MCL [MRDL]

PHG (MCLG) [MRDLG]

STATE DLR/ CCRDL(RL)

RANGE AVERAGE

REGULATED IN DISTRIBUTION SYSTEM

MAJOR SOURCES IN DRINKING WATER

Total Coliform Bacteria (State Total Coliform Rule)

%

5.0 (b)

(0)

–

–

Highest % of positive samples  collected in any one  month = 0%

Naturally present  in the environment

Fecal Coliform and E. Coli (State Total Coliform Rule)

(c)

(c)

(0)

–

–

Total number of positive samples  collected in 2024 = 0

Human and  animal fecal waste

Total  Coliform Bacteria (Federal Total Coliform Rule)

%

TT (d)

–

–

–

Highest % of positive samples  collected in any one month = 0%

Naturally present  in the environment

Fecal  Coliform and E. Coli (Federal Total Coliform Rule)

(e)

(e)

(0)

–

–

Total number  of positive samples collected in 2024  = 0

Human and  animal fecal waste

Heterotrophic Plate Count (HPC)

CFU/mL

TT

NA

NA

Range

Distribution  System Wide: ND-969

Naturally present in the environment

Average

Distribution  System Wide: 25

RADIOACTIVE CONTAMINANTS (f)

PARAMETER

UNITS

STATE MCL [MRDL]

PHG (MCLG) [MRDLG]

STATE DLR/ CCRDL(RL)

RANGE AVERAGE

STATE PROJECT WATER

COLORADO RIVER WATER

GROUND WATER

TREATED AVERAGE SYSTEM WATER

MAJOR SOURCES IN DRINKING WATER

Gross Alpha  Particle Activity (k)

pCi/L

15

(0)

3

Range

ND

ND - 3.2

ND - 7.5

–

Erosion of natural deposits

Average

ND

3.84

Uranium

pCi/L

20

0.43

1

Range

ND

2.8 - 3.1

ND - 16.8

–

Erosion of natural deposits

Average

2.9

4.71

Primary Standards – (continued)

INORGANIC CONTAMINANTS

PARAMETER

UNITS

STATE MCL [MRDL]

PHG (MCLG) [MRDLG]

STATE DLR/ CCRDL(RL)

RANGE AVERAGE

STATE PROJECT WATER

COLORADO RIVER WATER

GROUND WATER

TREATED AVERAGE SYSTEM WATER

MAJOR SOURCES IN DRINKING WATER

Arsenic

µg/L

10

0.004

2

Range

ND

2

ND - 6.5

ND - 2

Erosion of natural  deposits; runoff from  orchards; glass and electronics production wastes

Average

ND

ND

Barium

mg/L

1

2

0.1

Range

ND

0.13

ND - 0.13

ND - 0.13

Discharges of oil drilling wastes and from metal refineries; erosion of natural deposits

Average

ND

ND

Chromium (hexavalent)

µg/L

10

0.02

0.1

Range

ND

ND

ND - 8.2

ND

Erosion of natural deposits;  transformation of naturally occurring  trivalent chromium to hexavalent chromium by natural processes and human activities such as discharges from  electroplating factories, leather tanneries, wood preservation, chemical synthesis, refractory production, and textile manufacturing facilities.

Average

ND

Fluoride (e,  h)

mg/L

2.0

1

0.1

Range

0.6 - 0.9

0.3 - 0.4

0.26 - 2.0

ND - 0.78

Erosion  of natural deposits; water additive that promotes strong  teeth; discharge from fertilizer and aluminum factories

Average

0.7

0.3

0.4

0.22

Nitrate (as Nitrogen) (k, t)

mg/L

10

(as N)

10

(as N)

0.4

Range

0.6

ND

ND - 20

ND - 5.9

Runoff and leaching from fertilizer use; leaching from septic  tanks and sewage; erosion of natural deposits

Average

9.5

2.3

Perchlorate (k, s)

µg/L

6

1

1

Range

ND

ND

ND - 9.4

ND - 2.9

Perchlorate is an inorganic chemical used in solid rocket propellant, fireworks, explosives, flares, matches, and a variety of industries. It usually gets into drinking water as a result of environmental contamination from historic

aerospace or other industrial operations that used  or use, store, or dispose of perchlorate and its salts.

Average

3.3

ND

SYNTHETIC ORGANIC CONTAMINANTS including Pesticides/PCBs

1,2,3-Trichloropropane (1,2,3-TCP)(k, s, t)

µg/L

0.005

0.0007

0.005

Range

ND

ND

ND - 0.02

ND

Discharge from industrial and agricultural chemical  factories; leaching from hazardous waste sites; used as cleaning and maintenance solvent, paint and varnish remover,  and cleaning and degreasing agent; byproduct during the production of other compounds and pesticides.

Average

ND

VOLATILE ORGANIC CONTAMINANTS

PARAMETER

UNITS

STATE MCL [MRDL]

PHG (MCLG) [MRDLG]

STATE DLR/ CCRDL(RL)

RANGE AVERAGE

STATE PROJECT WATER

COLORADO RIVER WATER

GROUND WATER

TREATED AVERAGE SYSTEM WATER

MAJOR SOURCES IN DRINKING WATER

Tetrachloroethylene (PCE)

µg/L

5

0.06

0.5

Range

ND

ND

ND - 1

ND

Discharge from factories, dry cleaners, and auto shops (metal degreaser)

Average

ND

Trichloroethylene (TCE)

µg/L

5

1.7

0.5

Range

ND

ND

ND - 1.1

ND

Discharge from metal  degreasing sites and other factories

Average

ND

Secondary Standards – Aesthetic Standards

PARAMETER

UNITS

STATE MCL [MRDL]

PHG (MCLG) [MRDLG]

STATE DLR/ CCRDL(RL)

RANGE AVERAGE

STATE PROJECT WATER

COLORADO RIVER WATER

GROUND WATER

TREATED AVERAGE SYSTEM WATER

MAJOR SOURCES IN DRINKING WATER

Aluminum (i)

µg/L

200

600

50

Range

ND - 110

ND

ND

ND - 230

Erosion of natural  deposits; residual from  some surface water treatment processes

Max RAA

ND

120

Chloride

mg/L

500

NA

NA

Range

41 - 67

108

110 - 210

16 - 120

Runoff/leaching from natural deposits; seawater influence

Average

54

–

162

71

Color

units

15

NA

(1)

Range

1 - 2

3

ND - 3

–

Naturally-occurring organic materials

Average

2

ND

Corrosivity

(as Aggressiveness Index)

AI

NA

NA

NA

Range

12.2 - 12.3

–

12 - 13

10 - 12

Elemental balance in water; affected by temperature, other  factors

Average

12.2

13

12

Foaming Agents  –

Methylene Blue Active Substances (MBAS)

µg/L

500

NA

(50)

Range

ND

ND

ND - 120

ND

Municipal and industrial waste discharges

Average

36

Manganese (f, k)

µg/L

50

NL=500

(5)

Range

ND

ND

ND - 580

ND

Leaching from natural deposits

Average

49

Odor Threshold

Units

3

NA

1

Range

1

5

ND - 2

ND - 1

Naturally-occurring organic materials

Average

ND

ND

Specific Conductance (k)

µS/cm

1,600

NA

NA

Range

317 - 466

1,040 - 1,050

1,011 - 1,800

115 - 3,037

Substances that form  ions when in water; seawater influence

Average

392

1,040

1,374

655

Sulfate

mg/L

500

NA

0.5

Range

21 - 47

231 - 240

140 - 260

3.0 - 240

Runoff/leaching from natural  deposits; industrial wastes

Average

34

236

197

127

Total Dissolved Solids

(j, k, s)

mg/L

1,000

NA

(2)

Range

178 - 263

663 - 696

610 - 1,200

64 - 700

Runoff/leaching from natural deposits

Average

220

680

872

408

Turbidity

NTU

5

NA

0.1

Range

ND

0.6 - 1.3

0.1 - 0.55

0.15 - 0.2

Soil runoff

Average

0.9

0.18

0.17

Unregulated Contaminants with No MCLs (g)

PARAMETER

UNITS

STATE MCL [MRDL]

PHG (MCLG) [MRDLG]

STATE DLR/ CCRDL(RL)

RANGE AVERAGE

STATE PROJECT WATER

COLORADO RIVER WATER

GROUND WATER

TREATED AVERAGE SYSTEM WATER

HEALTH EFFECTS

Boron (p)

mg/L

NL=1

NA

0.1

Range

0.13

0.15

0.29 - 3.4

0.11 - 0.41

Boron exposures resulted in decreased fetal  weight (developmental effects) in newborn rats.

Average

1.33

0.24

Vanadium

µg/L

NL=50

NA

3

Range

ND

ND

ND - 19

ND - 3.9

Vanadium exposures resulted in developmental and repro-ductive effects in rats.

Average

6.39

ND

Perfluoroalkyl and Polyfluoroalkyl Substances (PFAS) with Notification Levels,Analyzed by EPA Methods 533 (s)

PARAMETER

UNITS

STATE MCL [MRDL]

PHG (MCLG) [MRDLG]

STATE DLR/ CCRDL(RL)

RANGE AVERAGE

STATE PROJECT WATER

COLORADO RIVER WATER

GROUND WATER

TREATED AVERAGE SYSTEM WATER

HEALTH EFFECTS

Perfluorobutane Sulfonic (PFBS)

ng/L

NL=500

NA

3

Range

ND

ND

ND - 52

ND - 2.2

Industrial chemical factory discharges; runoff/leaching from landfills; used in fire-retarding foams  and various industrial processes

Average

20

ND

Perfluorohexane Sulfonic Acid (PFHxS)

ng/L

NL=3

NA

3

Range

ND

ND

ND - 68

ND

Average

22

Perfluorooctanoic Acid (PFOA)

ng/L

NL=5.1

0.007

4

Range

ND

ND

ND - 300

ND - 4.3

Industrial chemical factory discharges; runoff/leaching from landfills; used in fire-retarding foams  and various industrial processes

Average

80

ND

Perfluorooctanesulfonate Acid (PFOS)

ng/L

NL=6.5

1

4

Range

ND

ND

ND - 330

ND - 4.2

Average

93

ND

Disinfection Byproducts,Disinfectant Residuals, and Disinfection Byproduct Precursors Federal Rule (m)

PARAMETER

UNITS

STATE MCL [MRDL]

PHG (MCLG) [MRDLG]

STATE DLR/ CCRDL(RL)

RANGE AVERAGE/ LRAA/RAA

DISTRIBUTION SYSTEM WIDE

MAJOR SOURCES IN DRINKING WATER

HEALTH EFFECTS LANGUAGE

Total Trihalomethanes (TTHMs) (n)

µg/L

80

NA

1

Range

ND - 34

Byproduct of drinking water disinfection

Some people who drink water  containing trihalomethanes in excess of the MCL over  many years may experience liver,  kidney, or central  nervous system problems, and may have an increased risk of getting cancer.

LRAA

29.3

Haloacetic Acids (HAA5) (o)

µg/L

60

NA

1

Range

ND - 11

Byproduct of drinking water disinfection

Some people who drink  water containing haloacetic acids in excess  of the MCL over many years may have an increased risk of getting cancer.

LRAA

9.7

Bromate (Mills - WR-24 Conn.) (l)

µg/L

10

0.1

1

Range

ND - 19

Byproduct of drinking water disinfection

Some people who drink  water containing bromate  in excess of the MCL over many years may have an increased risk of getting cancer.

Max RAA

7.9

Chloramines

mg/L

[4 as Cl2]

[4 as Cl2]

NA

Range

1.21 – 2.8

Drinking water  disinfectant added for treatment

Some people who use  water containing chloramines  well in excess of the MRDL could  experience irritating effects  to their eyes and nose.  Some people who  drink water containing chloramines well in excess of  the MRDL could experience stomach discomfort or anemia.

Max RAA

2.0

Control of DBP precursors (TOC)

mg/L

TT

NA

0.3

Range

2.2 - 2.7

Various natural and manmade sources

Total organic carbon (TOC)  has no health effects. However, total organic  carbon provides a medium  for the formation of disinfection byproducts. These byproducts include trihalomethanes (THMs) and  haloacetic acids (HAAs). Drinking  water containing these byproducts in excess of the MCL may lead to adverse health  effects, liver or kidney problems, or nervous system  effects, and may lead to an increased risk of cancer.

Average

2.4

Other Parameters

CHEMICAL

UNITS

STATE MCL [MRDL]

PHG (MCLG) [MRDLG]

STATE DLR/ CCRDL(RL)

RANGE AVERAGE

STATE PROJECT WATER

COLORADO RIVER WATER

GROUND WATER

TREATED AVERAGE SYSTEM WATER

Alkalinity

mg/L

NA

NA

(1)

Range

68 - 71

123 - 128

120 - 390

16 - 130

Average

70

126

230

79

Bicarbonate

mg/L

NA

NA

NA

Range

–

–

120 - 390

14 - 130

Average

230

78

Calcium

mg/L

NA

NA

(0.1)

Range

15 - 22

72 - 75

55 - 170

1.6 - 83

Average

18

74

118

43

Hardness (q)

mg/L

NA

NA

(1)

Range

68 - 99

291 - 296

200 - 590

5.5 - 320

Average

84

294

419

171

Magnesium

mg/L

NA

NA

(0.01)

Range

8.4 -11

28 - 29

15 - 45

0.37 - 30

Average

9.7

28

30

15

pH

pH Units

NA

NA

NA

Range

8.7 - 8.8

8.1 - 8.2

7.7 - 8.0

7.4 - 10.2

Average

8.7

8.1

7.9

7.5

Potassium

mg/L

NA

NA

(0.2)

Range

1.9 - 3.1

5.4

1.9 - 14

ND - 6

Average

2.5

5.4

3.3

Sodium (r)

mg/L

NA

NA

(1)

Range

35 - 54

104 - 108

54 - 180

21 - 110

Average

44

106

118

67

Federal Unregulated Contaminants MonitoringRule (UCMR 4) (u)

HALOACTIC ACID (HAA) GROUP

PARAMETER

UNITS

STATE MCL [MRDL]

PHG (MCLG) [MRDLG]

STATE DLR/ CCRDL(RL)

RANGE AVERAGE

DISTRIBUTION SYSTEM

HAA5 (o)

µg/L

NA

NA

NA

Range

ND-15.8

Average

5.9

HAA6Br (w)

µg/L

NA

NA

NA

Range

ND-17.3

Average

6.1

HAA9 (x)

µg/L

NA

NA

NA

Range

ND-28

Average

10.2

Total Organic Carbon

µg/L

NA

NA

NA

Range

ND-2,600

Average

1,925

Bromide

µg/L

NA

NA

NA

Range

ND-32

Average

15.3

METALS AND METALLOIDS GROUP

Manganese

µg/L

NA

NA

NA

Range

ND-62

Average

2

Federal Unregulated Contaminants MonitoringRule (UCMR 5) (v)

LITHIUM BY ICP

PARAMETER

UNITS

STATE MCL [MRDL]

PHG (MCLG) [MRDLG]

STATE DLR/ CCRDL(RL)

RANGE AVERAGE

DISTRIBUTION SYSTEM

Lithium

µg/L

NA

NA

9

Range

ND-55.1

Average

16

EPA 533

PFBA

µg/L

NA

NA

0.005

Range

ND-0.0076

Average

ND

PFHxA

µg/L

NA

NA

0.003

Range

ND-0.0038

Average

ND

PFHxS

µg/L

NA

NA

0.003

Range

ND-0.0033

Average

ND

PFPeA

µg/L

NA

NA

0.003

Range

ND-0.0061

Average

ND

Key to Abbreviations

AI               Aggressiveness Index

CCDLP    ConsumerConfidence Report Detection Level

CFU/mL   Colony-FormingUnits per Milliliter

DBP       Disinfection Byproducts

DLR       Detection Limits for purposesof Reporting

LRAA     Locational Running Annual Average

MBAS     Methylene Blue Active Substances

mg/L     Milligrams perliter or parts per million (ppm)

N          Nitrogen

NA      NotApplicable

ND      NotDetected

ng/L     Nanogramsper liter or parts per trillion (ppt)

NL       NotificationLevel

NTU     NephelometricTurbidity Units

pCi/L    PicoCuriesper liter

RAA       Running Annual Average

TOC       Total Organic Carbon

μS/cm   microSiemen per centimeter; or micromhoper centimeter (µmho/cm)

μg/L      Micrograms per liter or parts per billion (ppb)

Extended Abbreviations

MaximumContaminant Level (MCL):The highest level of a contaminant that is allowedin drinking water. Primary MCLs are set as close to the PHGs (orMCLGs) as is economically and technologically feasible. Secondary MCLs areset to protect the odor, taste and appearanceof drinking water.

Maximum Contaminant Level Goal (MCLG): The level ofa contaminantin drinkingwater below which there is no known or expectedrisk to health. MCLGs areset by the U.S. Environmental Protection Agency.

Public Health Goal (PHG): The level ofa contaminant in drinking water below which there is no known or expected risk to health. PHGs are set by theCalifornia Environmental Protection Agency.

PrimaryDrinking Water Standard(PDWS): MCLs and MRDLs for contaminants that affect health along with their monitoring and reporting requirements, and water treatment requirements.

Maximum Residual Disinfectant Level(MRDL): The highest level of a disinfectant allowed in drinking water. There is convincing evidence that addition of a disinfectant is necessary for control of microbialcontaminants.

Maximum Residual Disinfectant Level Goal (MRDLG): The level of a drinking water disinfectant below which there is no known or expected risk to health. MRDLGsdo not reflect the benefitsof the use of disinfectants to control microbial contaminants.

Regulatory Action Level (AL): The concentration of a contaminant which, ifexceeded, triggers treatment or other requirements that a water system must follow.

Treatment Technique (TT): A required process intended to reduce the level of a contaminant in drinking water.

Footnotes

(a)       The turbidity level of the filtered water shall be less than or equal to 0.3 NTU in 95% of the measurements taken each month and shall not exceed 1 NTU at any time. Turbidity, a measure of the cloudiness of the water, is anindicator of treatment performance. The averages and ranges of turbidity shown in the Secondary Standards were based onthe treatmentplant effluent.

(b)       Totalcoliform MCLs: No more than 5.0% of the monthly samples may be total coliform-positive. Compliance is based onthe combineddistribution system sampling from all the treatment plants. In 2024,1591 samples were analyzed and there were no positive detections for total coliform. The MCL was not violated.

(c)       E. coli MCL: The occurrence of two consecutive total coliform-positive samples, one of which containsE. coli, constitutes an acute MCL violation. The MCL was not violated.

(d)       Totalcoliform TT trigger, Level 1assessments, and total coliform TTviolations: More than 5.0% total coliform-positive samples ina month trigger Level 1 assessments. Failure to conduct assessments and correct findings within 30 days is a total coliformviolation. No triggers, Level 1 assessments, or violations occurred.

(e)     E. coli MCL and Level 2 TT triggersfor assessments: Routineand repeat samples are total coliform-positiveand either sample is E. coli-positive or system fails to collectall repeat samplesfollowing an E. coli-positive sample,or fails to test for E.coli when the repeat sample is total coliform-positive. No samples were E. coli-positive. No MCLs violations or no assessments occurred.

(f)      Results included in this section range from 2016-2024.

(g)     Unregulated contaminant monitoring helps the USEPA and the State Board determinewhere certain contaminants occur and whether the contaminants need to be regulated.

(h)     City of Corona was in compliance with all provisions of the State’sFluoridation System Requirements. This is part of the City of Corona’s blending plan to reduce the levels of fluoride being delivered to the consumer’s tap. Refer to the “Treated AverageSystem Water” column for a more accuraterepresentation of system water quality.

(i)      Aluminum has a secondary standard limit. In 2024 the secondary standard limit wasexceeded at our Treatment Facility effluent. The Maximum Running Annual Average (Max RAA) was 158 ug/L, no consumer actionis necessary since secondary standardsfor aluminumare establishedonly for aesthetic effects (water color). We are continually calibrating ouraluminum base coagulant to achieve the non-mandatory secondary standard limitof 200 ug/L.

(j)      Total DissolvedSolids (TDS) is a measureof the total amount of all the materials that aredissolved in water. These minerals, both natural and anthropogenic (made by humans), are mainly inorganic solids, with a minor amountof organic material.

(k)     Thisconstituent was detected at levels exceeding the MCL, results shown in bold.Please note that this water is blended with water from other sources to provide customers with the highest quality drinking water.

(l)      Reported from Mills Filtration Plant Metropolitan WaterDistrict (MWD). Mills MWD wateris blended with other Corona water sources. Please note that this water is blended with water from other sourcesto provide customerswith the highestquality drinking water.

(m)    The City of Coronawas in compliance with all provisions of the Stage2 Disinfectants and Disinfection Byproducts Rules (D/DBP). Compliance was based on the locational running annual average(LRAA). The averagereported reflectsthe highest TTHM and HAA5 LRAAs for the year.

(n)     Total Trihalomethanesis the sum of bromodichloromethane, bromoform, chloroform,and dibromochloromethane.

(o)  HAA5 is the sum of dichloroacetic acid, trichloroacetic acid, monobromoacetic acid, dibromoacetic acid, and monochloroacetic acid.

(p)  Thesources that were detected for Boron are all directed to the Temescal Desalterfor reverse osmosis treatment. Thetreated water is monitored at the effluent of the facility which is represented in the “Treated Average System Water” column.

(q)  Hardness is the sum of polyvalent cations present in the water, generally magnesium and calcium. The cations areusually naturally occurring.

(r)      Sodiumrefers to the salt present in the water and is generally naturally occurring.

(s)    Fluoride, nitrate, perchlorate, TDS, 1,2,3-TCP, PFOA, PFOS, PFBS and PFHxS are a part ofCorona’s blending remediation plan to reduce the levels being delivered to the consumer’s tap. Refer to the “TreatedAverage System Water” column for a more accurate representation of system water quality.

(t)      1,2,3-TCPwas monitored quarterly in Corona’s source and treated waters for the State’sinitial monitoring requirement and continues to be monitored per our BlendingPlan requirements.

(u)     UCMR 4 sampling took place from 2018-2019. Minimumreporting levels are as stipulatedin the Federal UCMR 4. Detected parameter results are included in the CCR.

(v)     UCMR 5sampling took place 2023-2024. Minimum reporting levels are as stipulatedin the Federal UCMR 5. Detected parameter results are included in the CCR.

(w)    HAA6Br: Bromochloroacetic acid, bromodichloroacetic acid, dibromoacetic acid, dibromochloroacetic acid, monobromoacetic acid, andtribromoacetic acid.

(x)     HAA9: Bromochloroacetic acid, bromodichloroacetic acid,chlorodibromoacetic acid, dibromoacetic acid, dichloroacetic acid, monobromoacetic acid, monochloroaceticacid, tribromoacetic acid, and trichloroacetic acid.

Frequently Asked Questions

How hardis my water?

Hardness is dissolved minerals, including calcium and magnesium. Thismay cause a deposit or water spots on fixturesand dishes. Our average hardness in the system is 171 ppm or 10 grains per gallon, whichis classified as hard. Our water hardness can change depending on the water demandand the season.

When I turn on my kitchen or bathroomfaucet, the water comes out white. What is wrong?

Dissolvedair in the water causes a milky appearance. When you turn on your faucet, the pressure is relieved and this allows the air to form bubbles that rise to the top of the glass. It will clear within a minute,beginning at the bottom of the glass. The water is safe to drink.

How do I flush mywater heater?

We have general instructions for flushing your waterheater; for specific instructionsconsult your user’s manual or look on the manufacturer’s website.

1. Turn the gas valve to “pilot.”

2. Hook up agarden hose to the water heater and find a proper location to drain the water; use caution – water will be hot whenit comes out.

3. Open thevalve until all of the hot water has drained from the water heater.

4. Close the valve where the garden hose is hooked up.

5. Allow the heater to fill up, and then close the cold water supply on top of thewater heater.

6.Open up the hose bib again and let it drain.

7. Repeat the cycle a couple of times.

8. Disconnect the garden hose,turn the watersupply back on andturn the gas valve to the “on” position.

My water pressure has been very high recently, what’s wrong?

The City has six separatewater pressure zones. Your pressure should beconstant throughout the day but may decrease3 - 5 pounds when systemdemands go up, such as during the night when a lot of water is used for irrigation. If your pressure has suddenly increased, it may mean thatyour pressure regulator needs to be adjustedor replaced. Call us at (951) 736-2234 and we will be happy to help troubleshoot the issue for you.

There is anodor coming from my water, what’s wrong? Is the water safe to drink?

We sometimesreceive phone calls from customers stating that their water smells.However, the source of the odor is usually not the water,but from something else in the home. To test this, simply fill a glass withwater and smell it. If the water itself doesnot smell, but you still smell the odor,there could be another issue such as a sink that needs to have the garbage disposal cleaned or run. A front-loadingwashing machine can also develop an odor from mold if the lid remains closed.

Did you know?

•There are 748 gallons of water in one unit of water.

•One acre-foot of water equals 325,829 gallons or 435.6 billing units.

•Oneacre-foot of water can supply two typical families with water for a whole year.

•A leaky toilet can waste between 30 to 500 gallons of water per day.

•Most hot water heater manufacturersrecommend annual flushing of the hotwater tank to remove sediment and stagnant water, which can lead to odors and clogged aerators.

To changethe language of this report, please select the language under “Translate” in the uppermenu features foundat www. CoronaCA.gov/CCRTranslation.

Español: Para cambiar el idioma de este reporte, seleccione el idioma en “Translate” en las funciones del menú que seencuentra en: www. CoronaCA.gov/CCRTranslation.

If you are interested in participating in decisionsthat affect the quality and supply of the water in the City of Corona,or for general information about this reportand questions related to water quality, please call (951) 736-2234.

Regular City Councilmeetings are held on the first and thirdWednesday of every month.

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