Backflow Prevention
Protecting And Eliminating Cross Connections
What Is Backflow?
Drinking water flows from the source
to your tap in pressurized water pipes. Normally it flows in one
direction, although under certain circumstances it can flow in the
opposite direction, or "backflow." When backflow occurs, water runs
backwards through the water system. The water flowing backwards
could contain something that might contaminate the drinking water
supply. TVWD strives to maintain positive pressure in the system at
all times, but events such as main breaks and fire fighting can
contribute to backflow conditions.
What Is A Cross Connection?
A cross connection is any connection between piping that carries drinking water (also known as potable water) and the piping or fixtures that carry other types of water or substances that are not safe to drink or may impact the taste or odor of water (also known as non-potable water). Common cross connections include hot tubs, sprinkler and irrigation systems and auxiliary water systems (wells).
Why Does TVWD Have A Backflow/Cross Connections Department?
Per Oregon Administrative Rule (OAR) 333-061-070 and District Rules and Regulations, all approved backflow prevention assembly must be maintained and tested at least annually to protect the public water system.
TVWD's Cross Connection Program seeks to eliminate or protect all cross connections in the public water system and help customers comply with backflow prevention practices and regulations. All backflow assemblies must be inspected once a year by a certified backflow tester to ensure proper operation. If you have a backflow assembly that is required to be tested, you will receive a letter from TVWD with guidance about how to get this done. Failure to comply with required testing will result in the disconnection of your water service.
If you are unsure if your water-using fixture needs a backflow assembly or an annual backflow test, contact your plumber, landscaper or TVWD's Cross Connections Department.
There are approved circumstances where testing your backflow assembly is not required for underground lawn irrigation systems. These circumstances include when the irrigation system is shut off for the entire year or is disconnected permanently. To apply for this variance, complete the Backflow assembly Non-Use Certification Form (PDF) and return to TVWD.
Gold Plan Backflow Test
For your convenience, TVWD has implemented a new backflow
assembly testing program for residential customers only. You may
now choose to have TVWD arrange for your backflow assembly(s) to be
tested annually by a certified tester.
The Gold Plan Backflow Test is being offered to TVWD
residential customers with a known backflow assembly. By
participating in this program, the District will schedule the
required annual backflow test and have the test performed by a
District contractor. This includes an allowance of up to $50 per
year in minor repairs to an existing assembly to achieve a passing
test. The cost to our customers who wish to join in this program is
$35 a year for each assembly they wish to include in this
program. This fee will be added to their water bill upon completion
of an assembly test. Customers will still receive only one
test notice per year.
Please note this is available to TVWD, Southwood Park and Valley
View customers only.
To review eligibility requirements, apply, or get more
information, take a look at the Backflow Contract Testing
Application in Rich Text File/Word or PDF.
For backflow assembly testers interested in our Gold Plan
Backflow assembly testers interested in testing should take a look at our TVWD Backflow Testers Handbook Contract (PDF), our Backflow Testers Invoice (PDF) or contact our Backflow Department.
Water Heater Thermal Expansion
Please note that you may need to protect your water heater from thermal expansion when you install a backflow prevention assembly at the water meter. This may be provided by the installation of a thermal expansion tank and a temperature and pressure relief valve. For more information, take a look at our Protect Your Water Heater From Thermal Expansion Brochure (PDF) or contact a licensed plumber.
More Backflow/Cross Connections Resources:
- Backflow Assembly Non-Use Certification Form (PDF)
- Backflow Testers Contract Invoice (PDF)
- Water System Standards (PDF) - contains backflow assembly specifications
- TVWD Rules and Regulations (PDF) - for TVWD's adopted Backflow and Cross Connection ordinances