Indiana backflow testing rules
Indiana's cross-connection rule is 327 IAC 8-10, and the Indiana Department of Environmental Management (IDEM) Drinking Water Branch runs the state Backflow Prevention and Cross Connection Control Program under it.
Who sets the rules in Indiana
IDEM's program is meant to make sure every public water system develops an effective cross connection control program for its entire distribution system.
Is an annual test required?
Under 327 IAC 8-10, customers of public water systems must install backflow prevention devices where required and have them tested at least once a year.
Indiana rule 327 IAC 8-10-8 requires each device to be tested by a cross connection control device inspector when installed and then at intervals not exceeding one year; this covers reduced pressure principle backflow preventers, double check valve assemblies and pressure and spill resistant vacuum breakers, and air gaps are inspected on the same yearly cycle.
Citizens Energy Group (Indianapolis) requires customers with a cross connection to have their devices tested by an IDEM certified tester at least once a year.
Sources: Devices tested at least once a year (state); Test intervals in 327 IAC 8-10-8; Citizens Water (Indianapolis): yearly test by an IDEM certified tester
Which properties need a backflow preventer
Indiana rule 327 IAC 8-10-4 lists facilities designated as cross connection hazards, among them car washes, hospitals and medical buildings, mortuaries, laboratories, chemical, metal and paper plants, commercial laundries and marinas; these need an air gap or reduced pressure principle backflow preventer on the service line when the facility is new, the service line is modified or a larger meter is installed.
Under Indiana rule 327 IAC 8-10-6, a buried lawn irrigation system with sprinkler outlets less than six inches above grade that was built after July 19, 1985 needs an air gap, a reduced pressure principle backflow preventer or a pressure type vacuum breaker on its supply line.
Indiana rule 327 IAC 8-10-5 requires an air gap, double check valve assembly or reduced pressure principle backflow preventer for a fire sprinkler system, and a reduced pressure principle backflow preventer where the sprinkler system has a chemical additive.
Indiana American Water requires a pressure type vacuum breaker or reduced pressure principle backflow preventer for all customers with lawn irrigation systems, including residential customers.
Evansville Water and Sewer Utility requires owners of homes or properties with a lawn sprinkler or irrigation system to have the backflow preventer inspected every year.
Sources: Designated hazard facilities (327 IAC 8-10-4); Indiana American Water: residential irrigation included; Evansville: home irrigation tested every year
Who may do the test
Under Indiana rule 327 IAC 8-10-9, every cross connection control device inspector (backflow tester) must be registered with the IDEM commissioner, must test and calibrate test equipment every year, and must tag each device after testing.
How the test report is filed
Indiana rule 327 IAC 8-10-9 requires the tester to send test results to the public water system and to the customer within 30 days of the test.
IDEM says results go on the Backflow Device Test Form, State Form 55788, submitted in the method the water system requires; forms are not sent to IDEM unless IDEM asks for them.
IDEM's instructions for State Form 55788 say the tester must be a current Indiana licensed backflow tester and the test equipment must have been calibrated within the last 12 months for the test to be valid.
Citizens Energy Group accepts backflow test results only through Aqua Backflow (TrackMyBackflow.com), and testers must be IDEM certified and registered with Aqua Backflow first.
Sources: Reports due within 30 days (327 IAC 8-10-9); State Form 55788, not sent to IDEM; Test gauge calibrated within 12 months; Citizens Water accepts results only through TrackMyBackflow
If a test is missed
Under Indiana rule 327 IAC 8-10-10, the IDEM commissioner shall order the water system to remove the meter or otherwise cut off service to a customer found to be violating the rule.
Indiana American Water gives a customer no more than 30 days after a failed test to repair or replace the device and submit a passing result, and failure to do so could end water service.
Sources: IDEM can order service cut off (327 IAC 8-10-10); Indiana American Water: 30 days to fix a failed device
Finding a tester
IDEM publishes a list of licensed backflow testers who are Registered Cross Connection Control Device Inspectors for Indiana.
IDEM's list of actively certified backflow device testers is sorted by county and city (list dated August 25, 2026).
South Bend Water Works points customers to the list of Indiana certified testers.
Sources: IDEM list of licensed testers; Active tester list by county; South Bend links to the state tester list
Common questions
Is backflow testing required every year in Indiana?
Yes. Indiana rule 327 IAC 8-10 requires backflow prevention devices to be tested when installed and at least once a year by a registered cross connection control device inspector.