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A backflow prevention device is a precautionary device approved by the State Office of Drinking Water and the University of Southern California (USC) Hydraulic Research Section that provides protection from potentially hazardous substances getting pushed or pulled back into the City water system. In situations where chemicals or contaminated water could possibly backflow due to back pressure or back siphonage, known as a “hazard”, a backflow prevention device is required to protect the integrity of the water distribution system.
Reduced Pressure Device
Hazards include a separate irrigation system on a property, a business that uses chemicals, a property with a sewage lift station, or a potential cross connection with an unknown source. All the proceeding hazards are considered “high hazard” situations and require what is known as a reduced pressure backflow prevention device. Reduced pressure (RP) backflow prevention devices have a reduced pressure zone in the center of the device with two independent working check valves that prevent water from flowing back into the water system. This device is required in high hazard situations per State Health Code Title 17.
Double Check Device
Properties might have “low hazards” such as a well, pumps, or a residential fire sprinkler system. Properties with low hazards are required by State Health Code Title 17 to install a double check (DC) backflow prevention device. The double check backflow prevention device is a valve assembly with two independent spring-loaded check valves that allow water to flow through the device to the property but prevent water from flowing backwards.
In-line Dual Check Valve
The In-line Dual Check Valve is a mechanical device designed to prevent backflow and back-siphonage into the drinking water system, it consists of two independently acting, spring-loaded check valves. Designed for use in “low hazard” cross-connections and continuous pressure applications. The intended application is for residential water systems at the service entrance to fire sprinklers.
Because it is not a testable backflow prevention device, the In-line Dual Check Valve is exempt from the yearly testing requirement. To ensure that the device is functioning properly, In-line Dual Checks must be replaced every 5 years. At this time, the In-line Dual Check is allowed for properties affected by the 2017 Tubbs-Adobe Fires only.
Backflow assemblies are mechanical devices that may fail over time and require repair or replacement. The USC List of Approved Backflow Prevention Assemblies includes many different manufacturer and model types. The failure rate for the most commonly used devices in Santa Rosa is shown below.
Calendar Year 2023
One Year Failure Rate (%)
A certified backflow tester from the City of Santa Rosa List of Certified Testers must test every backflow prevention device once a year. The annual testing requirement is mandated by the State in the California Code of Regulation, Title 17.
Whether or not anyone is living at the property, the backflow prevention device is doing its job to prevent water from moving backwards into the drinking water system and may need maintenance. The backflow prevention device must be tested once a year based on the time of installation of the device, not whether anyone was living on the property.
The Water Quality Section will mail a postcard to the address on record as a reminder that the backflow test is due. You can then contact a tester from the list of certified testers. You are given thirty days’ notice to have your device tested and passed by a certified tester.
You can contact a tester on the list of certified testers to set up a date for testing. In most cases, your backflow prevention device is located near the curb across the sidewalk from your water meter. If it the backflow prevention device is easily accessible, you do not need to be onsite for the test. Once you have decided on a tester, the tester will conduct the test and give a copy of the test report to Water Quality. After your annual test is completed with a passing test and our system is updated, your obligation for the year is completed. You will be notified again the following year 30 days before your next test is due. Tests are due the same time each year unless a device is replaced or extensively repaired. If the device is replaced or has extensive repairs, your testing date will reflect the date the new device was installed.
To schedule a backflow prevention device test, contact a tester on the list of certified testers.
If your backflow prevention device does not pass the annual test, talk with your tester for recommendations on repair or replacement. A passing test is required within 30 days of your test due date.
Currently, the charges range from approximately $50.00 to $150.00 a test. Please contact testers directly to inquire about costs. To schedule a backflow test, contact a tester on the list of certified testers. Santa Rosa Water does not endorse or recommend any company on this list, nor does Santa Rosa Water set pricing by these companies.
The City will have to turn off your City water service to protect the water system from possible hazards until your device is tested. You have a 30-day grace period after the due day to make sure your device passes its annual test.
Who pays for and arranges the test depends on the lease agreement. Please contact your landlord to discuss.
Your last test was late. That test was your test for the previous year. The test due date on your postcard is your test for this year. For example, if your test was due December 2021 and you had the test done February 2022, the February 2022 test is for 2021. You will need a test for 2022.
Each tester’s competency is certified by a national agency every 3 years. Testers use specialized testing equipment that is calibrated every year. As required by the State, the City also evaluates each tester to make sure they meet standards. The test does not take long when done by an experienced tester. The device being tested must maintain pressure - hold back water flow – at each check valve and meet strict specifications. Only test reports from testers on the list of certified testers are accepted by the City of Santa Rosa.
Backflow prevention devices should be wrapped with some type of insulation (bags, enclosures, etc.) during the winter months to avoid costly freeze damage. Consult your local hardware store, plumbing supply store, or irrigation experts for insulation materials.
In addition, an enclosure over a backflow prevention device may prevent vandalism.
The Water Quality section enforces the State Water Resources Control Board Division of Drinking Water regulations concerning backflow and cross-connection control. Under Section 64764 of the regulations, backflow prevention devices must be tested annually by certified testers. Additionally, the California Health and Safety Code Section 116805 allows the water supplier to charge water users with backflow prevention devices a fee to administer the backflow program. Effective July 19, 2010, the City of Santa Rosa Board of Public Utilities authorized a fee of $3.00 per month to be charged to customers in the Santa Rosa service area with a backflow prevention device covered under our backflow program. On December 16, 2013, that fee increased to $3.25 per month. The purpose of the fee is to recover costs associated with the backflow program from those who are required to maintain backflow prevention devices as required by State regulations. Santa Rosa Water’s policy is to charge fees to customers who use specific services so that those costs are paid by the user and not the general ratepayer base.
For those customers who are required to install a backflow prevention device, below you’ll find the necessary information including which devices are required, how to install a backflow prevention device, the importance of a thermal protection device, and City construction standards: