Illinois Administrative Code
Title 41 - FIRE PROTECTION
Part 175 - TECHNICAL REQUIREMENTS FOR UNDERGROUND STORAGE TANKS AND THE STORAGE, TRANSPORTATION, SALE AND USE OF PETROLEUM AND OTHER REGULATED SUBSTANCES
Subpart D - DESIGN, INSTALLATION AND CONSTRUCTION REQUIREMENTS
Section 175.430 - Clearance Required for USTs

a) Distance to Basements. No UST shall be less than 20 feet from any basement, cellar, pit or below-grade excavation on or off the property.

b) Distance to Sewers. Individual tanks and piping shall be buried so that the tops of the tanks and piping are lower than the bottom level of all sewers, manholes, catch-basins, cesspools, septic tanks, septic tank clean out stations, wells or cisterns within 20 feet, on or off the property, or tanks and piping shall maintain a full clearance of 20 feet. The term "sewer" includes sanitary and storm sewer lines out of motor fuel dispensing facilities and bulk facilities. These clearances shall not be required when a sewer line is constructed throughout of petroleum resistant piping.

c) Distance to Property Lines. Individual tanks shall be at least 20 feet to property lines unless these clearances on the side adjacent to a public street, alley or highway are waived by consent of the authority having immediate jurisdiction over the public street, alley or highway. In the event the clearances to property lines is waived by the consent of the authority having immediate jurisdiction over the public street, alley or highway, the required sewer clearances will be maintained.

d) Distance to Special Classes of Property. Tanks and dispensers shall maintain a clearance of not less than 300 feet to any mine shaft, air or escape shaft for any mine and 85 feet to any educational, health care or assembly occupancy, as defined in 41 Ill. Adm. Code 100. The distance shall be measured from the nearest points of tanks and pumps to the nearest points of buildings or shafts.

e) Tanks in service on October 1, 1985 (or after October 1, 1985 if approved by OSFM) may maintain existing underground tank clearances. Basements at motor fuel dispensing facilities existing on October 1, 1985 less than 20 feet from a UST shall be provided with mechanical ventilation. Only non-sparking explosion proof motors and compressors shall be permitted in these basements. Proof of compliance shall be submitted to OSFM.

f) Except for the 20-foot clearance distance to basements, the clearances required under this Section shall not be required when both tanks and piping are double-walled with interstitial monitoring. For these USTs, the minimum clearance shall be such as to avoid projecting loads onto underground sewers, utilities and other structures. The clearance must also be sufficient to ensure that site activity does not undermine the UST backfill materials (for example, pea gravel base) for any UST once in place.