40 CFR §280.31 · Every 3 years / every 60 days (impressed current)
Cathodic Protection: Testing and the 60-Day Inspection (40 CFR §280.31)
Steel UST systems with corrosion protection must keep that protection operating continuously — and prove it on two clocks: a cathodic protection test within 6 months of installation and at least every 3 years thereafter, plus a 60-day inspection for impressed-current systems.
The 3-year test (and the 6-month triggers)
All cathodic protection systems — galvanic (sacrificial anode) and impressed current alike — must be tested within 6 months of installation and at least every 3 years thereafter, by a qualified cathodic protection tester applying a recognized code of practice. Repairs restart a clock too: within 6 months following a repair to any cathodically protected UST system, the cathodic protection system must be retested (§280.33(e)).
The 60-day impressed-current inspection
Impressed-current systems must additionally be inspected every 60 days to ensure they are running properly — in practice, confirming the rectifier is energized and recording its output voltage and amperage so the operating history is documented.
Records
Under §280.31(d), operators must maintain records demonstrating compliance: at minimum the results of the last three 60-day inspections and the last two 3-year tests. Temporary closure does not pause any of this — corrosion protection must continue to be operated and maintained for the entire closure period (§280.70(a)).
Citations
- 40 CFR §280.31
Citations verified against 40 CFR Part 280 primary-source text, June 2026. Regulations are amended — always confirm against the current eCFR and your state program before acting.