Colorado backflow testing rules
The Colorado Department of Public Health and Environment (CDPHE) Water Quality Control Division oversees backflow prevention and cross-connection control under Regulation 11, section 11.39 (5 CCR 1002-11), updated effective October 15, 2023.
Who sets the rules in Colorado
CDPHE publishes Policy 7, the Backflow Prevention and Cross-Connection Control Rule Policy, which explains how water systems carry out Regulation 11.39.
CDPHE says Colorado water suppliers run their own Backflow and Cross-Connection Control Programs, and it encourages them to use certified cross-connection control technicians.
Source: Colorado's backflow rule is Regulation 11, section 11.39
Is an annual test required?
Denver Water requires the customer to have each assembly tested when installed and every year after by a certified backflow prevention assembly tester.
Aurora (city ordinance 138-170) requires a Certified Backflow Technician to test every required assembly at installation and at least once a year after.
Sources: Denver Water: test at installation and every year; Aurora Water: test at installation and at least yearly
Which properties need a backflow preventer
Denver Water requires an approved backflow prevention assembly on all commercial, industrial, domestic, irrigation and fire line services; single and multi-family homes are assessed by site hazard.
Longmont surveys all non-single-family connections; single-family homes may need a control measure for dedicated irrigation lines, home fire suppression systems or boilers.
Sources: Denver Water: commercial, irrigation and fire lines need an assembly; Longmont: some single-family homes need control
Who may do the test
Under Colorado HB25-1077 (signed March 28, 2025), certified cross-connection control technicians may inspect, test and repair backflow prevention devices.
HB25-1077 amended C.R.S. 12-155-118 so that people who inspect, test or repair backflow prevention devices no longer need a plumbing licence, while people who install or remove them still do.
Colorado law (C.R.S. 25-8-107, added by HB25-1077) defines a certified cross-connection control technician as someone holding a valid backflow prevention assembly tester certification from ASSE or ABPA.
Since July 1, 2025, Colorado law (C.R.S. 25-8-107) requires a certified technician who tests or repairs a backflow device to attach a tag with the business name and contact, service date, a description of the work and the tester's ASSE or ABPA certification number.
Denver Water accepts testers holding ABPA or ASSE certification for domestic and irrigation assemblies; fire assemblies also need State of Colorado Fire Suppression System Contractor, Backflow certification.
Colorado Springs Utilities requires testers to upload a current ABPA or ASSE certification and test kit information to SwiftComply before they can submit tests.
Sources: HB25-1077: certified technicians may test and repair; Installing or removing a device still needs a plumbing licence; Certified technician means an ASSE or ABPA tester certificate; Denver Water: ABPA or ASSE testers; fire assemblies need the state backflow certification too; Colorado Springs Utilities: register in SwiftComply with ABPA or ASSE
How the test report is filed
Denver Water requires all testing to be reported to its Cross-Connection Control office; test reports go by email to crossconnectioncontrol@denverwater.org.
Denver Water's test report form says failed tests must be reported within 24 hours of the failure, at 303-628-5969.
Aurora Water requires test results to be submitted online at its backflow site before the annual test due date.
Colorado Springs Utilities requires commercial and multifamily irrigation assemblies to be tested and reported each year by July 1, and domestic and fire suppression assemblies by October 1.
Since February 2, 2026, Longmont requires testers to submit reports through SwiftComply, with a $10.00 charge for each passing test; failed tests are not charged.
Sources: Denver Water: reports by email; Denver Water: failed tests reported within 24 hours; Aurora Water: results online before the due date; Colorado Springs Utilities: irrigation due July 1, domestic and fire due Oct. 1; Longmont: SwiftComply, $10 per passing test
If a test is missed
Denver Water charges a non-refundable $250 penalty when three mailed notices go unanswered and the service goes into suspension.
Colorado Springs Utilities fines $405 per backflow assembly and suspends water service until compliance when annual testing is missed.
Longmont assesses a civil penalty of up to $500 per assembly and schedules a water service interruption 91 days after a missed backflow test due date.
Sources: Denver Water: $250 penalty after suspension; Colorado Springs Utilities: $405 per assembly; Longmont: civil penalty up to $500 per assembly at 91 days
Finding a tester
Colorado Springs Utilities publishes a table of registered backflow testers with phone numbers on its backflow prevention page.
Common questions
Is backflow testing required every year in Colorado?
Colorado water suppliers run their own backflow programs under Regulation 11.39, so your utility sets the schedule. For example, Denver Water and Aurora Water require each assembly to be tested at installation and every year after.