There is no single retention period for UST records. There are at least twelve, spread across four sections of 40 CFR 280, running from one year to the life of the equipment, and three of them are not measured in years at all. A site that clears its binder on one schedule will be missing something.
The table
| Record | Keep for | Source |
|---|---|---|
| Walkthrough inspections, monthly and annual | 1 year | 280.36(b) |
| Spill prevention, sump and overfill testing | 3 years | 280.35(c)(1) |
| Documentation for double walled equipment under the monitoring exemption | As long as the equipment is in use | 280.35(c)(2) |
| Written performance claims for a release detection system | 5 years from installation | 280.45(a) |
| Site assessments under 280.43(e)(6) and (f)(7) | As long as the method is used | 280.45(a) |
| Results of sampling, testing or monitoring | 1 year | 280.45(b) |
| Annual operation test results | 3 years | 280.45(b)(1) |
| Tank tightness test results | Until the next test is conducted | 280.45(b)(2) |
| Calibration, maintenance and repair of on-site release detection equipment | 1 year after the work | 280.45(c) |
| Manufacturer's calibration and maintenance schedules | 5 years from installation | 280.45(c) |
| Cathodic protection 60-day inspections | The last three | 280.31(d)(1) |
| Cathodic protection periodic tests | The last two | 280.31(d)(2) |
Federal minimums under 40 CFR part 280, current as of 28 August 2026. Several carry the phrase "or another reasonable period of time determined by the implementing agency", so a state may require longer.
The three that are not years
Tank tightness test results are kept until the next test is conducted. 280.45(b)(2). On a tank that has moved to monthly monitoring and may never be tightness tested again, that means the last one is kept indefinitely, because the next test never comes.
Cathodic protection records are counted, not dated. 280.31(d) asks for the last three 60-day inspections and the last two periodic tests. On a three year test cycle the second of those reaches back about six years, which is why a site that changed hands needs the previous owner's last CP report. No amount of testing going forward supplies a document from before you bought the place.
Double walled equipment documentation is kept for as long as the equipment is in use. 280.35(c)(2). If you are relying on monitoring rather than the three year liquid tightness test, the paperwork proving the equipment is double walled and monitored has no expiry while the equipment is in the ground.
One year is the trap
Three categories sit at one year, and they are the ones generated most often: walkthrough inspections, routine monitoring results, and calibration or repair documentation for on-site release detection equipment.
Twelve walkthrough records and twelve monitoring records a year, kept twelve months, sitting in the same folder as test reports kept three years and CP records kept by count. A single annual clear-out is legal for the first group and destroys the second.
Worth saying plainly: the legal minimum and the useful period are different questions. When an operator is arguing about when a problem started, or a buyer is asking what the site has been doing, a year of history answers very little.
What an annual operation test record has to say
280.45(b)(1) does something unusual. It sets a three year retention and then specifies the content:
- List each component tested.
- Indicate whether each component tested meets the criteria in 280.40(a)(3), or needs action taken.
- Describe any action taken to correct an issue.
A contractor invoice reading "annual release detection test, performed" satisfies none of that. Neither does a pass certificate with no component list. Ask for the component-level report at the time of the visit, because reconstructing it eleven months later means asking a technician what they found on a site they have visited forty times since.
The walkthrough record under 280.36(b) carries a similar content rule: each area checked, whether it was acceptable or needed action, a description of the action, and delivery records where the longer spill bucket interval is used.
Where the records live
280.34(c) gives two options. At the UST site and immediately available for inspection. Or at a readily available alternative site, and provided to the inspector on request.
Immediately available is the standard worth designing to. An inspector at the forecourt asking for last month's walkthrough does not want to hear that it is in a filing cabinet in another town. The alternative-site option exists and it works, and it works better when somebody at the site can produce the document on a screen while the question is being asked.
Records that outlive the site
Two situations catch operators out. Buying a site brings you its retention obligations, so the previous owner's cathodic protection tests and tightness test results are part of what you are acquiring. Ask for them in diligence, in writing, alongside the tank registration.
Closing a tank brings its own set under a different subpart, and a permanently closed tank does not free you from the records that describe what was in the ground.
How FastDragon handles it
Evidence is attached to the requirement it closes rather than filed by date, which is what makes retention answerable per record instead of per binder. A tank tightness result stays attached to its tank until a newer one replaces it, and the cathodic protection history keeps the count the rule asks for rather than a rolling window of months.
The records screen is built for the moment somebody is standing next to an inspector: search by site, requirement or date, and the photographs and the report open from the record. Nothing has to be retrieved from an office.
Common questions
What is the shortest retention period in the rule?
One year, and it applies to the records generated most often: walkthrough inspections under 280.36(b), the results of routine sampling, testing or monitoring under 280.45(b), and documentation of calibration, maintenance and repair of on-site release detection equipment under 280.45(c). A binder cleared annually loses nothing legally, and loses the history you would want in a dispute.
Which records are not measured in years at all?
Three. Tank tightness test results are kept until the next test is conducted, under 280.45(b)(2). Cathodic protection records are counted rather than dated: the last three 60-day inspections and the last two periodic tests, under 280.31(d). And documentation showing double walled equipment is monitored rather than tested is kept for as long as the equipment is in use, under 280.35(c)(2).
Can records be kept somewhere other than the site?
40 CFR 280.34(c) allows records to be kept at the UST site and immediately available for inspection, or at a readily available alternative site and provided on request. Immediately available is the phrase that matters. If your records live in an office forty miles away, the practical answer is a copy the person at the site can produce while the inspector is standing there.
Does my state set longer periods?
It can. Several of the federal periods carry the phrase or another reasonable period of time determined by the implementing agency, which is the clause a state uses to extend them. Check your own regulator before setting a destruction schedule, and where the two differ, keep to the longer one.
What has to be in an annual operation test record?
280.45(b)(1) is specific. The results must list each component tested, indicate whether each component meets the criteria in 280.40(a)(3) or needs action taken, and describe any action taken to correct an issue. A contractor's invoice saying the annual test was performed does not satisfy that.