Backflow Testing & Prevention in Meridian, ID
Backflow prevention keeps water from your lawn sprinkler lines, hose connections, or equipment from being pulled back into the city's drinking water. In Meridian this is not optional. If a sprinkler system connects to city water, the city requires an approved backflow assembly, and that assembly has to be tested every year.
We handle the annual test, repairs after a failed test, and replacements that need a permit. Call 24/7 if an assembly has frozen or burst.
I got a notice from the city about my sprinklers. What does it mean?
Most Meridian homeowners first hear the word backflow in a letter from the City Water Division. The notice usually means one of three things: your annual test is due, a test report came back failed, or an inspector found a cross connection that has to be removed.
All three point to the same device, the backflow assembly that sits on the sprinkler supply line, usually near the foundation or in a valve box in the yard. This page explains what each notice asks of you and how to clear it.
Neighboring Kuna takes the same rule further, and its water report says homes that skip the annual test can have their water turned off.
If a freeze has already cracked the assembly or a sprinkler line, frozen pipe repair covers the thaw and the split, and a meter that keeps moving afterward is a job for hidden leak detection.
The rule applies across Meridian's part of Ada County, from Old Town lots near Main Street to the newer subdivisions north of Chinden, wherever a sprinkler system ties into city water.
Why Meridian requires backflow protection
Water normally flows one way, from the city main into your house. A drop in city pressure, such as a main break or firefighting nearby, can reverse that flow. Without protection, water sitting in sprinkler lines can be siphoned back into the drinking water system along with fertilizer, lawn chemicals, and soil bacteria.
That is why the City of Meridian requires an approved backflow assembly on any sprinkler system connected to city water. The assembly must be tested once a year by a certified backflow assembly tester, and the result is filed with the City Water Division.
Passing reports go to the city within 15 days of the test. Failed reports go in within two business days, which starts the repair clock.
Assembly types you may find on a Meridian home
The city accepts specific assembly types for lawn sprinklers. Older homes sometimes have a type that no longer qualifies.
| Assembly | Where you see it | Status for lawn sprinklers |
|---|---|---|
| Pressure vacuum breaker (PVB) | Above ground, at least 12 inches above the highest sprinkler head | Accepted. |
| Reduced pressure assembly (RPBA or RP) | Above ground, often in an insulated cover | Accepted. |
| Double check assembly | Often below ground in a valve box | No longer allowed for lawn sprinklers since May 1, 2018. |
Assembly rules summarized from the City of Meridian Water Division backflow program.
If your home still has a double check assembly on the sprinkler line, expect a replacement to come up at the next test or inspection. Replacing it is permitted work, and the permit comes from Meridian Building Services at City Hall.
Dual connections and pressurized irrigation
Much of Meridian gets irrigation water from pressurized irrigation systems fed by the area's canals, separate from the city's drinking water. The Nampa-Meridian and Settlers irrigation districts still serve the area, as they have since the town's farming days.
Some homes were plumbed so the sprinkler system could draw from either source. The city calls this a dual or cross connection, and it is not allowed for residential use. If one is found, it has to be removed so the sprinklers draw from one source only.
Removal usually means cutting and capping the city water feed to the sprinkler system, or the reverse, and confirming the remaining connection has the right protection. Testers are required to report interconnects they find, so these tend to surface during annual testing.
If your assembly failed its test
A failed test is common and usually fixable. The city gives you 10 business days from the failed report to complete the repair and submit a passing retest.
- Check the tester's report for what failed, such as a check valve or relief valve.
- Call to schedule the repair soon, since parts for some models take time to arrive.
- If the assembly is old or no longer accepted, plan for replacement and the permit it needs.
- Make sure the passing retest report is filed with the Water Division before the deadline.
Most repairs involve cleaning or replacing rubber seats, springs, or checks inside the assembly. A replacement is the better choice when the body is cracked from freezing or the model is obsolete.
Winterizing the backflow assembly
Frozen assemblies are one of the most common emergency calls in Meridian each fall. The city recommends blowing out sprinklers and winterizing the backflow before October 31.
- Shut off the water to the sprinkler system at its isolation valve.
- Open the test cocks on the assembly to let trapped water drain.
- Blow out the sprinkler zones with compressed air, or have them blown out.
- Leave the test cocks partly open through winter, and cover or insulate the assembly.
If an assembly has already split from freezing, shut the isolation valve and call. Replacing a frozen assembly requires a permit, and we handle that for you.
What affects the cost of backflow work
An annual test is a predictable cost. Repairs and replacements vary with these factors.
- Test only, or test plus repair on the same visit.
- The make, model, and size of the assembly, and parts availability.
- Whether a replacement needs a new type to meet current rules.
- Permit and inspection for any replacement.
- Dual connection removal, which depends on how the lines were run.
Want your actual number? Call (208) 679-8357 with your tester's report or the city notice, and we will price the work before anything starts.
Need a backflow test or repair in Meridian?
Call now and we will help you meet the Water Division deadline.
Backflow questions from Meridian homeowners
How often does a backflow assembly need testing in Meridian?
Once a year. The test must be done by a certified backflow assembly tester, and the report goes to the City of Meridian Water Division.
Do I need a backflow preventer if my sprinklers use pressurized irrigation?
The city's requirement applies to sprinkler systems connected to city water. If your system draws only from pressurized irrigation, it may not need one, but it must not also connect to city water.
What happens if I miss the deadline after a failed test?
The city expects the repair and a passing retest within 10 business days. Missing it can lead to follow-up from the Water Division, so call as soon as the failed report comes in.
Why is my double check assembly no longer allowed?
Since May 1, 2018, the city no longer accepts double check assemblies for lawn sprinkler use. Existing ones are typically replaced with a pressure vacuum breaker or reduced pressure assembly.
Do I need a permit to replace a backflow assembly?
Yes. A permit from Meridian Building Services is required before replacing a backflow prevention assembly.
Can a frozen backflow preventer be repaired?
Sometimes a frozen part can be replaced. If the brass body cracked, the assembly needs to be replaced, which requires a permit.