Idaho backflow testing rules
Idaho's public drinking water rules (IDAPA 58.01.08, Subsection 552.06), administered by the Idaho Department of Environmental Quality, require every community water system to run a cross connection control program.
Who sets the rules in Idaho
Under IDAPA 58.01.08.552.06, the water purveyor is responsible for enforcing its own cross connection control program.
The Idaho Department of Environmental Quality says community water systems must have a cross-connection control program to prevent cross connections and backflow into the drinking water supply.
Sources: Community water systems must run a cross connection program; DEQ: programs required for community systems
Is an annual test required?
IDAPA 58.01.08.552.06 requires annual inspection and testing of all installed backflow prevention assemblies by a licensed tester, using the USC Foundation test procedures.
Under IDAPA 58.01.08.552.07, non-community water systems must also have backflow prevention assemblies inspected and tested every year by an Idaho licensed tester.
Coeur d'Alene says the property owner must have the assembly tested so that no more than one year passes between inspections, and the city must receive a passing report before that deadline.
Idaho Falls City Code 8-4-36 requires backflow prevention assemblies, except atmospheric vacuum breakers, to be tested by a certified tester when installed and every year after.
Sources: Annual testing of every installed assembly; Coeur d'Alene: no more than one year between tests; Idaho Falls: tested at installation and every year
Which properties need a backflow preventer
Under IDAPA 58.01.08.552.06, each community system's program must include inspections to find cross connections, and for new connections the system must verify protection was installed before providing water service.
IDAPA 58.01.08.543 requires double check, reduced pressure, spill resistant vacuum breaker and pressure vacuum breaker assemblies to have passed the USC Foundation performance test and be on its approved list.
The City of Eagle says a property with outside water sources connected to its drinking water must have the proper backflow assembly in use and tested every year.
The City of Twin Falls says there is no grandfathering of its backflow requirement, and every connection that needs a backflow preventer must have one installed.
Sources: Inspection program, and protection before new service; Eagle: homes with outside water connections; Twin Falls: no grandfathering
Who may do the test
In Idaho, backflow assembly testers are licensed under IDAPA 24.05.01, the rules of the Board of Drinking Water and Wastewater Professionals within the Division of Occupational and Professional Licenses (DOPL).
A 2011 joint memo from the Idaho State Fire Marshal and the Board of Drinking Water and Wastewater Professionals, hosted by DOPL, says testing a backflow assembly on an integrated fire sprinkler system needs a backflow assembly tester licence (Idaho Code 54-2402) and the person must also be a licensed fire sprinkler contractor or its agent (Idaho Code 41-254).
The City of Coeur d'Alene requires State of Idaho licensed backflow assembly testers to file a tester registration form with its Office of Cross Connection Control every year before testing in its service area.
Sources: Testers are licensed by the Board of Drinking Water and Wastewater Professionals; Fire sprinkler backflow work needs both licences; Coeur d'Alene: testers register with the city each year
How the test report is filed
Under IDAPA 24.05.01, when an assembly passes, the tester must send the report to the customer and the water system within 15 business days of the test.
Under IDAPA 24.05.01, when an assembly fails or is defective, the tester must send the report to the customer and the water system within 2 business days of the test.
If a test is missed
Under IDAPA 58.01.08.552.06, an assembly that fails its annual test must be repaired, replaced or isolated within 10 business days, or water service to it must be discontinued.
IDAPA 58.01.08.552.06 requires each community system's program to discontinue service to any premises where suitable backflow protection has not been provided for a cross connection.
Eagle sets a yearly due date for test results (June 16 in 2026) and says missing it could result in termination of water service until the results are received.
Sources: Failed assemblies: 10 business days or service is cut; Eagle: missed deadline can stop water service
Finding a tester
Coeur d'Alene posts separate lists of backflow assembly testers for landscape irrigation, non-residential and fire sprinkler assemblies.
Eagle tells property owners to confirm their tester is currently certified by DOPL, and posts a backflow tester list for its area.
Sources: Coeur d'Alene publishes tester lists; Eagle: check the tester's DOPL licence
Common questions
Is backflow testing required every year in Idaho?
Yes. Idaho's drinking water rules (IDAPA 58.01.08.552.06) require every installed backflow prevention assembly to be inspected and tested each year by a licensed tester.