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UST Program - Available Local Guidance (LG) Letters

UST Program - Local Guidance (LG) 43


October 8, 1986

To: Local Agencies
We have received several questions regarding the need to report underground storage tank leaks that occur during a precision tank test.  An underground storage tank leak report need not be filed with the State Water Resources Control Board (State Board) if the leak occurs only during a precision test and less than one gallon of the hazardous substance is released.

In many cases, a tank system fails a precision test only because portions of the system are exposed to product or pressure not normally present during operating conditions.  That is to say, a release or leak only occurs during the test period, and the amount of substance lost is very small (a properly conducted precision test will detect a release of substantially less than one gallon during the test period).  General procedures under these circumstances call for excavation of the piping and top of the tank, looking for evidence of a leak, tightening pipe connections and manway covers, and retesting.  If the system proves tight during the retest, then the excavation is backfilled and the tank is placed back into operation.

Cases such as those described above do not need to be reported to the State Board.  However, this in no way affects the owner's responsibility to report the tank test results to the local agency.  If it is unclear whether the tank leaked in the past or if more than one gallon was released during the precision test, then a leak report should be filed with the State Board.

It is not the State Board's intent here to establish a minimum reportable quantity for an unauthorized release.  All releases, regardless of quantity, not associated with a failed precision test should be reported.

In summary, an underground storage tank leak report need not be filed with the State Board if a tank system falls a precision test and:

    1. The system passes upon retest; or
    2. Excavation of piping and top of tank shows no evidence of a past leak and the system passes the precision test following tightening of piping and manway covers; and
    3. Loss of substance during the test is minimal; i.e., less than one gallon.

If you have any questions, contact us.


[Original signed by:]

James W. Baetge, Chief
Division of Water Quality

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