Water Rate Changes FAQ

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Proposed Water and Reclaimed Water Rate Change Frequently Asked Questions  

PROP 218

1. What is the Prop 218 notice that I just received?  

  • Proposition 218 was approved by California voters in November 1996, it requires the City to provide written notice by mail to the tenant and owner/s of each parcel upon which the water rate will take effect.  
  • Proposition 218 requires a 45-day comment period before the City Council may act on the proposed water rates and finalize the tabulation of any protests received. 

2. Will the City of Corona Department of Water and Power (DWP) be presenting any information regarding the water rate changes?  

 Yes, DWP will host 4 community meetings.   





TemescalDesalter, 745 Public Safety Way

7 pm – 8pm


City Hall Council Chambers, 400 S.VicentiaAve

9am – 10am


Temescal Desalter, 745 Public Safety Way

7 pm – 8pm


Temescal Desalter, 745 Public Safety Way

7 pm – 8pm



1. If approved when will water rates change?  
If approved new water rates will be effective on January 19, 2020 but will not reflect on your bill until March 2020. 

2. Are there any discounts to lower my bills? 
There are no discounts to lower bills. There is an income-based program, Lifeline, which residents can see if they qualify for.  

3. If funding is needed, why are the water rates being reduced? 
The rates for indoor water usage is lower because this water is used for sanitary purposes and as such should be the lowest cost per unit.  

4. What is the Temporary Revenue Stability Charge (TRSC)? 
The Temporary Revenue Stability Charge, TRSC, is an extra charge applied to every unit of water delivered during the billing period. The TRSC only applies if a City-wide Water Conservation Stage 3 (Stage 3) or higher is declared. 

5. When was the last Stage 3 declared?  
The last Stage 3 was declared in 2015.  

6. Who can declare the City be in the water conservation Stage 3?  
DWP’s General Manager can declare the City as being in Stage 3.  

7. Is the TRSC going to be a permanent fee? 
No, the TRSC is not a permanent fee. It is only charged if the City declares a Water Conservation Stage 3 or higher. 

8. Why do we get charged this fee, TRSC, if we are not in a drought?
You will not be charged the TRSC fee unless the City is in Water Conservation Stage 3 or higher.  As of October 2019 we are not in Water Conservation Stage 3, so no TRSC fee would apply. 

9. How will this affect my bill if I’m not directly billed by DWP? (Apartments) 
DWP sends one bill to the building, for example an apartment complex. It is up to building management in how they wish to divide and bill their tenants. 

10. How many gallons are in 1 billing unit? 
There are 748 gallons in 1 billing unit. 



1. What was the rate study process? 
A water rate consultant was hired and went over all documented costs and revenue requirements, went over the cost of the services, and designed and calculated rates. 

2. Who conducted the independent rate study?  
Raftelis Financial Consultants, Inc. performed the independent rate study.  

3. How does a rate increase come to pass? 
A rate study is conducted, upon results it is decided if any changes or updates are needed. If changes to the rates are necessary, the City (DWP) initiates a Proposition 218 process. DWP presented the rate study and the proposed changes to the water rate at a council study session on October 9th and mailed out a notice to customers on October 18th about an upcoming public hearing on the proposed rates, which will be held on December 4th. If the rate study is adopted by the City Council in December, the rates will become effective in January 2020 and you would see changes to your bill in February 2020. 

4. What is an example of a future project DWP plans to build? 
The City plans to build the Keith Water Storage Tank in southeastern Corona at Nelson and Keith streets which will provide a redundant supply of potable water and fire protection for our community. Water storage tanks needed can cost between 6 to 9 million dollars.  

5. What was the order from the State that said we have to make these water cut backs? 
 In 2015 the State of California was in a severe drought, prompting emergency regulations required to achieve mandatory cutbacks of 28%. Although the statewide drought has ended, the State has in the past and since then issued mandates and efficiency regulations in order to manage California’s water supply. Even if there isn’t a declared drought, there are still regulations which require efficient water use.

The State of California has set a goal of 55 gallons per person per day as an efficient indoor water use goal. The State Water Resources Control Board will be implementing permanent conservation requirements in the future, based on Executive Order B-37-16.

Since 2010 the State has adopted the California Model Water Efficient Landscape Ordinance, which uses 80% of evapotranspiration for existing landscapes.

In order to make sure that we can adequately supply water to our customers and meet current and future mandates, DWP is proposing to change the water budget changes to help encourage further conservation and the concept that we must use water efficiently all of the time.



1. Why is the 1” Ready to Serve charge going up so much more than the ¾”?  
Charges were calculated based on the AWWA standards for capacity. Water meters are given a capacity ratio that is used to relate the amount of flow through each meter size to that of a 5/8” meter. A 3/4” meter has 1.5 times the capacity of a 5/8” meter, and 1” meter has 2.5 times the capacity of a 5/8” meter.

2. ow was my meter size determined?
Meters are properly sized for each residence based on the number of fixtures to meet the demand for water needed. Residences with fire sprinklers cannot downsize their water meters because the residence requires a certain demand for the fire sprinklers. Please call Customer Care for more information.   



1. How are you going to cut the water budget but raise the prices? 

DWP has mostly fixed costs that do not go away, even when water use goes down. The rates are designed to recover the cost of providing water service and a lot of that goes towards costs that do not change such as customer service, regulatory monitoring and reporting, and maintaining all of the wells, treatment plants and pipes that are used to treat and deliver water to our customers. Unfortunately this does result in higher unit costs even though less water is used. 

2. How did you come up with the Outdoor Efficiency Factor of 0.80? 

The 0.80 is based on the California Model Water Efficient Landscape Ordinance. The City of Corona adopted the California Model Water Efficient Landscape Ordinance in 2010 by Ordinance No. 3027. The Model Water Efficient Landscape Ordinance applies a factor of 0.7 to new development landscaping and 0.8 to existing landscaping.

3. How many gallons per person are allowed? 

The water budget formula will now calculate using 55 gallons per person. Assembly Bill 1668 and Senate Bill 606 are the new pair of laws that enacted the 55-gallon target.  

4. What is Evapotranspiration (ET)? 

Evapotranspiration, or ET, is the amount of water that is lost each day due to evaporation and plant transpiration. Evaporation is water lost from the soil due to factors such as wind, humidity and temperature. Plant transpiration is the amount of water that plants lose from their leaves and plant tissues. Evapotranspiration is an indicator of how much water crops, lawns, gardens and trees need for healthy growth and productivity. By measuring evapotranspiration, only the amount of water that is lost will be put back into the soil, therefore reducing water waste.  

The evapotranspiration rate is measured daily, in inches.  

For your water budget, the ET for each day in the billing cycle is added up and used to calculate your outdoor budget. There is a higher evapotranspiration rate in the summer than in the winter, when the weather is warmer. Your budget will adjust each month to account for evapotranspiration, so your budget will be higher in the summer than in the winter. The ET data that Corona is using for the tiered rates comes from a CIMIS (California Irrigation Management Information System) weather station data located at UC Riverside. For more information on CIMIS, visit  

5. Where does the weather (evapotranspiration) information come from? 

The Corona Department of Water & Power uses weather data information from the California Irrigation Management Information System (CIMIS) Station #44, located at U.C. Riverside. 

6. What if I go over my budget? 

Please check your household to see if you have any type of break or leak that needs to be corrected. It is also a good idea to check your irrigation system to see if there is a leak or broken sprinkler that is causing an increase in your water usage. The irrigation timer may also need to be adjusted to the current weather conditions. Once the cause of the increase is found and corrected, call Customer Care at (951) 736-2321 and ask if you can get a variance adjustment on your bill that is over budget. Check out our website at for other water saving tips, as well as information on current rebate programs that are being offered. 

7. What if I have more than 4 people in my household? 

You may call Customer Care or submit a variance form online. Changes to your account will be made to accurately reflect your household and the changes will become effective with your next billing cycle. 

8. What if I think my landscape area is wrong? 

You will need to call Customer Care or submit a variance form online along with a sketch of your property on an 8 ½" x 11" sheet of paper to DWP. After review and if revisions are necessary, the changes to your account will become effective on your next billing cycle. 



1. What is the Ready-To-Serve charge? 
The Ready-to-Serve charge is for the water service connection and is paid by all users connected to the City's water system, whether or not any water is actually used. It is a fixed component of the cost of providing water based on the size of the meter. The Ready-to-Serve fee covers our fixed costs of providing water. Fixed costs include debt, regulatory compliance, providing fire flow, customer service, utility billing, personnel, preventive maintenance, etc. We want you to have water when you need it and in order to do that, we have to build and maintain the infrastructure to deliver water to you. In order to do that, we need to charge our customers a Ready-to-Serve fee. 

2. Are the new Ready-To-Serve charges going to be the same for the next 5 years, or do they gradually increase every year until they reach the final proposed rate charge? 
If approved the Ready-To-Serve charges will change over the next five years. The first change will take place starting on January 19, 2020. The next four changes will take place at the beginning of every January so in 2021, 2022, 2023, ending with the final change in 2024. 

3. Why is Reclaimed Readiness-To-Serve (RTS) less expensive than Potable RTS? 
The reclaimed RTS is less than the potable RTS because the reclaimed water system is smaller than the potable water system, meaning fewer miles of piping and fewer reclaimed water accounts. Additionally the assets are newer.

4. Why is the Ready to Serve charge showing two different charges between the notice I received on October 18th and the website?
During the final review of the Potable and Reclaimed Water Rate Study an update was made to one of the tables that impacted some of the Ready to Serve rates previously mailed to customers on October 18, 2019 in the Notice of Public Hearing. DWP will be providing this update via a bill insert as well. This table shows the current Ready to Serve rates, mailed rate, and correct proposed rate that would become effective January 19, 2020 if approved. We apologize for any confusion.

Water Rate Changes Update


1. We are currently in Stage 2 of the Water Conservation Ordinance which states I can water 3 days a week no more than 20 minutes per station, will I need to reduce my watering more with the new proposed water budget structure? What would be the suggested watering times?  
The ordinance allows watering on 3 days of the week up to 20 minutes per station. At this time the water times and days remain the same. The ordinance states the timer of each station should be set at no more than 20 minutes, it is advised the customer goes over the new proposed outdoor water budget and adjusts timer accordingly. 

2. What percentage of water cutback did Corona achieve towards the mandate of 28%? 
When the State placed a 28% water cutback mandate for the City from June 2015 through February 2016, the City was able to achieve a cumulative 19% cutback. 

3. What can I do to make sure that I stay within my new water budget? 
There are many ways you can ensure that you stay within your budget. The most important thing that you can do is check for breaks or leaks in your irrigation system. Check your indoor fixtures, such as toilets, faucets and your water softener. You may also want to take advantage of current rebates on water efficient devices and landscape discount partnerships that the Corona Department of Water & Power is offering to help you save water. Call our Water Resources team at (951) 736-2234 for more information on water conservation. 

4. Is the Water Conservation Ordinance changing? 
No, the Water Conservation Ordinance will remain in effect. 

5. Do I still have to comply with the watering guidelines? 
The City encourages everyone to follow Stage 2 of the Water Conservation Ordinance. That means that you should only water on specific days depending on the number of your address. Odd number addresses can only water Saturday, Monday and Wednesday. Even number addresses can only water Sunday, Tuesday and Thursday. The Corona Department of Water & Power wants to help you comply with these guidelines. Please call the Water Resources Team at (951) 736-2234 if you have any questions. 

6. Do I still have to water within the watering window? 
Yes. Watering should only be done before 10 a.m. and after 8 p.m. Watering during this window allows the water to absorb into the soil, instead of evaporating from the sun or heat during the middle of the day, or blowing off the surface of your landscaping by the wind. For more information or to learn how to adjust your sprinklers, please call the Water Resources Team at (951) 736-2234 or visit our website

7. I don’t want my grass to die; are there rebates or anything else I can do? 
DWP has a program that allows residents to receive a rebate to replace live grass with drought tolerant landscaping. You can learn more and apply for the rebate at  

8. How can I conserve and what will the City do to help me?
The quickest way to save water is in your outside landscaping. About half of the urban water is used for landscape irrigation in California. The potential for water savings is huge! Consider lowering the minutes on your irrigation controller. You can train your landscaping to use less water. Install water efficient rotating sprinkler nozzles and a smart irrigation controller that reduces your run times automatically based on the weather. Install a rain barrel to capture rain water that you can use for your landscaping.  

If you're interested in saving water indoors, consider installing water conserving devices such as premium high efficiency toilets, high efficiency clothes washers, faucet aerators, low-flow showerheads and more. Through the Metropolitan Water District, Western Municipal Water District and the Corona Department of Water & Power, you can receive a rebate for purchasing premium high efficiency toilets or a high efficiency clothes washer. For more information, please visit The Corona Department of Water & Power also provides faucet aerators, low flow showerheads, and 5-minute shower timers to customers for free. Please contact us today to request any of these conservation items at (951) 736-2234 or e-mail us at  



1. How can I test my own water? 
If you wish to sample and test the water quality at your residence you may contact a certified laboratory.  



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