Wyoming Administrative Code
Agency 020 - Environmental Quality, Dept. of
Sub-Agency 0011 - Water Quality
Chapter 17 - STORAGE TANKS
Part D - UST SYSTEMS: RELEASE DETECTION
Section 17-15 - Petroleum USTs with a capacity of 2,000 gallons or less

(i) Tank liquid level measurements shall be taken at the beginning and ending of a period of at least thirty-six (36) hours during which no liquid is added to or removed from the tank;

(ii) Level measurements shall be based on an average of two (2) consecutive stick readings at both the beginning and end of the period;

(iii) The equipment used shall be capable of measuring the depth of the regulated substance over the full range of the USTs height to the nearest one-eighth (1/8) of an inch;

(iv) A suspected release shall be declared and the requirements of Part E shall be followed if the variation between beginning and ending measurements exceeds the weekly or monthly standards in Table 1;

* Nothing can be added to or removed from the UST for the duration of the test.

(v) Owners and/or operators of USTs of one thousand (1000) gallons or less nominal capacity may use Manual Tank Gauging as the sole method of release detection. Owners and/or operators of USTs of one thousand one (1001) to two thousand (2,000) gallons may use manual tank gauging, combined with tank tightness testing at least every five (5) years until ten (10) years after the UST itself first met the requirements of Section 6(a). After ten (10) years, owners and/or operators of these tanks may not use manual tank gauging. Owners and/or operators of USTs of greater than two thousand (2,000) gallons nominal capacity may not use manual tank gauging.