California's progress removing aging single-walled storage tanks

Single-walled storage tanks must close by January 1, 2026

The dangers of storage tank leaks

  • Leaking fuel and hazardous waste can pollute:
    • Soil
    • Groundwater
    • Streams
    • Other drinking water sources
  • Fuel vapor seeping out of the ground can harm people's health and even cause explosions.

Up to

30%

of tanks left may leak due to rust and corrosion

  • Cleanup of polluted sites is extremely costly and can take many years.

Diagram illustrating the pollution effects of single-walled storage tanks
Single-walled storage tanks can leak fuel and toxins into the water and soil.
Rusted, exposed single-walled storage tank

Owners had 11 years to comply

Owners of remaining single-walled USTs were notified in 2014 of California's requirement to permanently close all single-walled UST systems by December 31, 2025.

California is almost done

49,350

(99.9%)

out of original 50,000 single-walled tanks have been closed


  • Less than 650 single-walled tanks remain:
    • 530 now have permit applications.
    • 225 tanks have scheduled removal start dates.

About 120 tanks on 50 sites are not yet in formal planning for removal.

Funding and assistance

The State Water Board has provided:

$183.1

million

in grants and loans to 630 different owners, mainly to remove singled-walled tanks


$80

million

for single-wall tank removal since 2023


Owners can still apply for Removing Underground Storage Tank loans.

The UST Cleanup Fund, which reimburses for contamination cleanup costs after leaks, has been extended by AB 1115 to January 1, 2036, to ensure owners and operators can meet financial responsibility requirements.

Diagram illustrating the pollution effects of single-walled storage tanks
Streams, groundwater, sewage lines, residential wells and beaches can be polluted when corroding single-walled tanks leak underground.

Single-walled tank locations in California



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