Underground Storage Tanks (UST) Disclosure

Underground storage tanks (USTs) are containers with at least 10% of their volume below ground, used to store petroleum products or hazardous substances. California has more regulated USTs than any other state. USTs are regulated under the federal Resource Conservation and Recovery Act (RCRA, Subtitle I) and in California under Health & Safety Code §§25280–25299.8.

USTs are the most common source of soil and groundwater contamination in California commercial real estate. Gas stations, auto repair shops, dry cleaners, industrial facilities, and former agricultural operations frequently have current or former USTs. Leaking underground storage tanks (LUSTs) can cost $100,000 to over $1 million to remediate.

CUPA = Certified Unified Program Agency (county environmental health or fire department).

When a UST leaks, the site is reported to the State Water Resources Control Board (SWRCB) and tracked in the GeoTracker database. LUST sites with active cleanup cases are included on the Cortese List (Government Code §65962.5), which triggers mandatory disclosure in California real estate transactions. The Verity NHD report queries GeoTracker to identify LUST sites within the statutory search radius.

There are currently over 14,000 open LUST cleanup cases in California and more than 45,000 closed cases. Even closed LUST sites may have residual contamination affecting property value, insurance availability, and redevelopment potential.

California imposes multiple disclosure obligations related to USTs:

• Seller disclosure (Civil Code §1102.6): Sellers must disclose known environmental hazards including current or former USTs
• Cortese List disclosure (Gov. Code §65962.5): NHD reports must identify properties near known LUST sites
• UST permit disclosure: Active UST operating permits are public records available through the local CUPA
• Tank closure reports: When a UST is removed or closed in place, a closure report documenting sampling results is a public record
• Land use covenant: Sites with residual contamination may have a recorded deed restriction limiting future land use

When acquiring commercial property with UST history:

• Order a Phase I Environmental Site Assessment (ASTM E1527-21)
• Request UST closure reports and sampling data from the CUPA
• Check GeoTracker (geotracker.waterboards.ca.gov) for the property and adjacent parcels
• Review the SWRCB case file for open LUST cleanup cases
• Verify financial assurance — confirm UST Cleanup Fund eligibility (H&S Code §25299.10)
• Obtain an opinion of probable remediation cost if contamination is known
• Negotiate environmental indemnification and escrow holdback provisions

The California Underground Storage Tank Cleanup Fund (H&S Code §25299.10 et seq.) provides reimbursement to eligible UST owners and operators for corrective action costs. Eligible claimants can receive up to $1.5 million per occurrence after a deductible. Eligibility requires timely reporting and compliance with SWRCB directives. Buyers should verify fund eligibility as part of due diligence.

• RCRA Subtitle I (42 U.S.C. §6991 et seq.) — Federal UST regulations
• Health & Safety Code §§25280–25299.8 — California UST law
• Health & Safety Code §25299.10 et seq. — UST Cleanup Fund
• 23 CCR §§2610–2714 — UST monitoring and reporting regulations
• Government Code §65962.5 — Cortese List (LUST disclosure trigger)
• Civil Code §1102.6 — Seller environmental disclosure
• Water Code §13304 — SWRCB authority over discharges