Underground Storage Tanks

Placement Restrictions (F-3208.2)

  • Flammable liquid storage tanks shall be placed a minimum of 1 foot from any wall and 3 feet from any lot line.
  • Combustible liquid storage tanks shall be placed a minimum of 1 foot from any wall and 1 foot from any lot line.

Excavation Restrictions (F-3208.3)

  • Minimum backfill underneath each tank shall be 1 foot.
  • Maximum depth shall be twice the diameter of the tank or 23 feet, whichever is less.

Ground Water & Flood Protection Requirements (F-3208.4)

  • Hold down straps per manufacturer's specifications.
  • Hold down pad separated from the tank by a minimum of 6 inches (steel tank) or 12 inches (non-metallic tank).

Installation & Backfill Requirements (F-3208.5)

  • Minimum backfill for a steel tank: 12 inches
  • Minimum backfill for a non-metallic tank: 24 inches
  • Backfill must be non-corrosive, inert material (for example, pea gravel, crushed rock, sand, etc.)
  • Minimum diameter (pea gravel): 1/2 inch
  • Maximum diameter (pea gravel): 3/4 inch
  • Minimum diameter (crushed rock): 1/8 inch
  • Maximum diameter (crushed rock): 1/2 inch

Tank Coverage in Traffic Areas (F-3208.6)

  • Option No. 1: minimum backfill of 18 inches with 6 inches of reinforced concrete.
  • Option No. 2: minimum backfill of 30 inches with 6 inches of asphalt.
  • Note in both cases, the cover must extend a minimum of 1 foot beyond the vertically projected line of the storage tank.

Corrosion Protection (F-3208)

All steel underground storage tanks and/or associated metallic equipment/devices shall be protected from corrosion. Metallic connections to steel tanks shall be by dielectric fittings. Metallic hold down straps shall be electrically isolated from steel tanks.

Leak Detection (F-3208.9)

All underground storage tanks and piping systems shall be monitored in an approved manner.

Tank Testing (F-3208.10)

After installation and prior to adding flammable or combustible liquids, the tank shall be pressure tested to a minimum of 3 psi and a maximum of 5 psi for 60 minutes (1 hour) without additional air/gas being added.

Abandonment of Underground Tanks (F3208.11)

After 1 year or if determined to be leaking, the underground storage tank and its associated piping must be removed and the site restored/remediated is an appropriate manner.