Louisville's annual backflow tests are due by Sept. 30, filed through BSI Online.
Louisville backflow rules at a glance
| Water provider | City of Louisville, Cross Connection Control Program |
|---|---|
| Who | Commercial, non-single-family residential, industrial, institutional, and irrigation connections |
| Deadline | Tested every year by Sept. 30 |
| How reports are filed | Through BSI Online. The tester or testing company pays BSI's filing fee. |
| Notices | BSI sends testing, past-due, and failed-test notices for the city |
| Home sprinkler systems | Residential lawn sprinkler devices are isolation assemblies; the city recommends testing them every year |
| Program help | BSI Online: testers 800-414-4990, property owners 888-966-6050 |
Summarized from City of Louisville's published program information (source), checked October 2026. The notice from your water provider always has the final word on your due date.
The notice comes from BSI
Louisville hands its notices to Backflow Solutions, Inc., so the letter or email may carry BSI's name instead of the city's. It's legitimate. The Sept. 30 deadline is the city's. Louisville moved to a new website in 2026, and its water and sewer page now lists BSI's numbers: 800-414-4990 for testers and 888-966-6050 for property owners. The program details above come from the city's cross-connection page as it read in January 2026.
Lawn sprinklers
The city recommends testing residential sprinkler backflow devices every year, and a test is the easiest way to catch a cracked or leaking assembly after a hard winter. We can pair it with a spring startup or a fall blowout.
What we do on a Louisville backflow test
- Confirm the assembly type, size, and serial number against your provider's records
- Test every check valve and relief valve with a differential pressure gauge calibrated October 2026 and traceable to NIST
- Tag the assembly with the service date, our business information, and the tester's certification number
- File the completed report the way City of Louisville requires
- Send you a copy of the report, with photos
If the assembly fails
Most failures come down to a dirty or worn check valve, a tired relief valve, or a split rubber part. Those get cleaned or rebuilt and retested, usually in the same visit, after you approve the price. If the body itself is cracked, usually from a missed winterization, the assembly has to be replaced. Replacing an assembly is installation work, which in Colorado needs a licensed plumber; we'll tell you exactly what's needed and do the retest once it's in.
Before we come out
- Have the notice from your water provider handy, or send a photo of it when you book
- Tell us where the assembly is, and leave any gate unlocked or the mechanical room open
- For sprinkler assemblies, the water needs to be on. If the system is still winterized, we can do the spring startup and the test in one visit.
Not sure what kind of assembly you have? PVB vs. DCVA vs. RPZ →
Backflow testing nearby
Denver · Aurora · Thornton · Westminster · Arvada · Northglenn · Broomfield · Golden · Lakewood · Englewood · Commerce City · Wheat Ridge · Parker · Boulder · Lafayette · Greenwood Village · Centennial · Commercial & HOA testing · For plumbing & irrigation companies · Every provider's rules
More in Louisville: all plumbing services in Louisville