Underground storage tanks
Underground storage tanks (USTs) sit at gas stations, fleet yards, airports, and plenty of small businesses. The federal UST rule (40 CFR Part 280) sets what has to be checked and how often, and your state program enforces it. These guides cover each piece of equipment.
What gets checked, and how often
Most UST compliance runs on three clocks: every 30 days, every year, and every 3 years.
| How often | What | Guide |
|---|---|---|
| Every 30 days | Walkthrough inspection, including spill buckets (EPA) | Spill buckets |
| Every year | Line leak detector test on pressurized piping, plus a line tightness test unless you monitor monthly (EPA) | Line leak detectors |
| Every 3 years | Spill bucket tightness test (single-wall) (40 CFR 280.35) | Spill buckets |
| Every 3 years | Overfill prevention inspection (EPA) | Overfill prevention |
The federal rule also covers release detection for the tanks themselves, containment sumps, corrosion protection, and operator training. Guides on those are coming.
Your state runs the program. Most states adopted the federal rule and inspect against it, sometimes with their own forms and extra requirements. Michigan, for example, adopted the federal testing schedule (Mich. Admin. Code R 29.2120). Check with your state UST program.
All underground tank guides
- Spill bucket testing
The 30-day walkthrough, the 3-year test, how the water and vacuum tests work, and what fails.
- Line leak detectors
How mechanical and electronic detectors work, what the yearly test checks, and why a dispenser drops to a trickle.
- Overfill prevention
Shutoff valves, alarms, and ball floats, the 3-year inspection, and how to order fuel so it never gets close.
Have aboveground tanks too? See the aboveground fuel tanks guide. For the fuel inside, see the fuel quality guides.