Tennessee backflow testing rules

Who sets the rules in Tennessee

Rule 0400-45-01-.17(6)(b)2: after approval, each community water system must establish an ongoing program; records must include testing results.

Rule 0400-45-01-.17(6)(b)3 requires plans and policies to conform to the Department's Cross-Connection Control Manual and Design Criteria.

Rule 0400-45-01-.17(6)(b)4: community systems ensure customer cross-connections are surveyed or inspected and eliminated or controlled by an approved backflow preventer.

Source: Every community water system must write an approved cross-connection control plan

Is an annual test required?

The rule itself (0400-45-01-.17(6)) mentions testing results in records but sets no frequency. TDEC's Cross-Connection Control Manual (guidance only, Feb 2025) says assemblies should be tested at least every 12 months and the water purveyor enforces it.

TDEC Division of Water Supply criteria in the manual tell water purveyors to see that assemblies are tested after installation and at least annually.

The TDEC manual states it is guidance only and does not create legal rights or obligations; binding force comes from the rule plus each system's approved ordinance.

Source: State rule text does not set annual testing; TDEC guidance says at least annually

Which properties need a backflow preventer

Appendix L of the TDEC manual names both commercial and residential lawn irrigation as cross-connections protected by RP or RP detector assemblies, tested annually, with the first test at start-up (typically within 90 days).

Appendix L: assemblies on public-water irrigation must be tested annually, not just before winterization.

Appendix M covers residential and commercial fire sprinkler systems; any assembly the public water supply requires must be tested annually (testing may be regulated by other state departments).

Appendix M: non-health fire sprinkler systems minimum double check valve; systems with chemical additives are health hazards needing RP assemblies. Some residential flow-through systems need none.

Per the TDEC manual Appendix L, residential irrigation on public water needs an RP assembly; double checks cannot be used for premise isolation on irrigation.

Appendix M: residential closed fire systems are non-health hazards needing double check; flow-through domestic-connected types are exempt.

Source: TDEC guidance: lawn irrigation, commercial and residential, is a cross-connection needing RPZ and annual test

Who may do the test

TDEC guidance: only tests by persons holding a valid Certificate of Competency are official tests for water systems; certificates are not transferable.

Appendix K (State Guidance for Voluntary Certificate): testers are encouraged to hold the state certificate; providers may add restrictions and may refuse reports from lapsed certificates.

Model ordinance language in the manual: a tester needs approval from the water system before test reports are accepted.

Source: State certificate of competency is what water systems treat as an official test

How the test report is filed

TDEC guidance: the water provider keeps correspondence and documentation for each assembly, including test reports, for at least five years. Reports must be on a Division approved form.

Manual 5.10: a full signed tester report is maintained in the water system's cross-connection files.

Source: Test reports go to the water system, which keeps them 5 years

If a test is missed

TDEC manual: the purveyor should discontinue service where assemblies are not tested or maintained acceptably.

Manual 5.11 suggested schedule: Day 0 letter, Day 30 second notice, Day 60 certified letter, Day 90 service discontinued, with faster action for high risk sites.

Source: Guidance: service discontinued for failure to test or maintain assemblies

Finding a tester

TDEC Fleming Training Center publishes a public dataviewer of active and inactive testers at https://dataviewers.tdec.tn.gov/pls/enf_reports/f?p=205:6 (roster not scraped).

Source: TDEC Tennessee Backflow Testers dataviewer