Backflow Testing in Denver, CO

Why Denver Water cares about backflow

Backflow is water moving the wrong way, out of a building or sprinkler system and back toward the public supply. It can happen through backsiphonage, when pressure in the main drops during a main break or heavy firefighting draw, or through backpressure, when a pump or boiler pushes building pressure higher than the street. An assembly at the service keeps that water from reaching the system everyone drinks from.

Who has to test

• Commercial and industrial services: an approved assembly is required.
• Irrigation services: must be protected by a reduced pressure principle assembly (RP) or a pressure vacuum breaker (PVB). Denver Water does not allow atmospheric vacuum breakers for irrigation.
• Fire lines: an assembly is required, and the tester also needs a Colorado Fire Suppression System Contractor-Backflow certification.
• Homes: requirements for single-family and multifamily residences depend on the hazards at the site.
• Properties with a well or pond: an auxiliary supply means an assembly must be installed and maintained.

How the yearly cycle works

1. The assembly is tested at installation, then once a year.
2. The tester must hold ABPA or ASSE backflow certification.
3. Test reports go to Denver Water's Cross-Connection Control office.
4. Irrigation assemblies are tested from May through September as systems are turned on, and Denver Water sends a reminder before a test is due.

When the test fails

A failed test usually points to worn check valves, a fouled relief valve, torn rubber parts or debris caught in the assembly. Many can be rebuilt with a repair kit and retested the same visit. Older or damaged units may need replacement. Installing a new backflow preventer at a single-family home or duplex is a Denver quick permit through Community Planning and Development.

Sprinkler assemblies and Front Range winters

Irrigation assemblies sit outside, and hard freezes with fast temperature swings can crack bodies and bonnets that still hold water. Draining the assembly and blowing out the lines each fall prevents most spring surprises.

What affects the cost

Pricing depends on the assembly type and size, how many assemblies are on the property, access to the vault or enclosure, whether parts or a rebuild are needed, and whether a replacement and permit are involved.