If you own or manage a shop, restaurant, salon, office, clinic, or apartment building, your water provider will probably ask for a backflow test once a year. Here’s why, which businesses the state names, and what the test involves.
Why businesses, and not houses
Colorado's drinking water rule, Regulation 11, requires every public water system to run a backflow prevention and cross-connection control program. Under it, water providers have to survey every non-single-family connection for cross connections: commercial, industrial, multi-family, and agricultural. Any connection serving three or more dwelling units counts. If the survey finds a cross connection, the provider has to control it, and providers can require a reduced pressure (RPZ) assembly in place of a survey.
Single-family homes and duplexes are handled differently. CDPHE considers them low risk and leaves typical home plumbing to local plumbing codes, although a provider can still require protection for setups like a dedicated irrigation line from the main, a well, or a permanently plumbed pool. That's why the yearly test notices go mostly to businesses, apartment buildings, and HOAs.
Businesses the state names
CDPHE's backflow FAQ lists these among the businesses whose connections can carry a cross-connection risk:
- Restaurants
- Hair salons
- Auto repair shops
- Car washes
- Dry cleaners and laundries
- Hospitals, dental offices, medical clinics, and blood banks
- Laboratories
- Mortuaries
- Veterinary clinics, pet stores, and livestock facilities
- Manufacturing facilities
- Greenhouses and agricultural businesses
- Bulk water fill stations
It also lists the equipment and uses that create cross connections at commercial properties:
- Irrigation systems, including dedicated irrigation lines from the water main
- Chemical process systems, including chemicals hooked up for maintenance
- Boilers, chillers, cooling towers, hydronic heating and cooling, heat exchangers, and solar panels
- Display fountains, pools, and hot tubs
- Wells and other auxiliary water, reclaimed water, greywater, and onsite storage tanks
- Fire sprinkler systems
Fire sprinkler backflow assemblies need a tester with the state's fire suppression registration, and several water providers require it. We test domestic, irrigation, and process assemblies.
What happens if you skip it
CDPHE's information for water customers says a customer who doesn't test on time can be fined or have the water turned off, and the miss can put the water system itself in violation. When that happens, the system may have to notify all of its customers within 30 days, and the notice can name the customer who caused it. State law (C.R.S. 25-1-114(1)(h)) makes it unlawful to create or allow a cross connection, and CDPHE says failing to test an assembly is essentially creating one.
Providers add their own penalties:
- Aurora Water: a $1,000 civil penalty once a test is 30 days past due, $2,000 at 60 days
- Denver Water: a $250 non-refundable penalty after three unanswered notices
- Thornton: failed tests reported within 24 hours, and water service can be disconnected
- Golden: service can be terminated for missed testing
Every provider's deadlines and filing rules, side by side: backflow testing requirements by provider.
What test day looks like at a business
- A certified tester checks each check valve and relief valve with a differential pressure gauge calibrated October 2026 and traceable to NIST.
- The water past the assembly is off for part of the test, so we schedule around your hours: before you open, during a slow stretch, or on a Saturday by appointment.
- The assembly gets a tag with the service date, our business information, and the tester's certification number, as Colorado has required since July 1, 2025.
- The report is filed the way your provider wants it (by email, Aurora Water's portal, BSI Online, Arvada's SAMS, and others), and you get a copy for your records.
- If something fails, you get a repair price before any work starts. Many failures are cleaned or rebuilt and retested in the same visit.
What it costs
First test $95 per device for new customers. Published prices around the Denver metro run about $90 to $125 per assembly for a standard test. Several assemblies at one site, or several locations, can be quoted together. What changes the price →
Got a notice?
Text a photo of it to (720) 818-5569. We'll tell you what it needs, then test, tag, and file it. Several locations or a portfolio? See commercial and HOA backflow testing. Plumbing or irrigation company without a tester? Subcontract your backflow tests.
Sources: CDPHE backflow prevention and cross-connection control program · CDPHE backflow FAQ (questions 8, 18 to 22, and 35 to 39) · CDPHE information for customers · Regulation 11, Section 11.39 · HB25-1077. Provider penalties come from each provider's own pages, linked on our provider pages. Checked October 27, 2026.