Delaware UST Regulations 2026: DNREC Tank Management Guide

Program Overview

DNREC TMS oversees just over 550 federally regulated systems plus state-regulated heating-oil tanks across Delaware. Each facility listing on UST Map mirrors TMS data fields—tank capacity, product lines, status, and corrosion method—helping brokers and lenders confirm disclosures before transactions. 2026 field priorities include ensuring monthly walkthroughs meet EPA’s walkthrough checklist and that release detection equipment passes annual functionality testing.

Registration & Operator Compliance

Owners must renew registrations annually and submit notifications at least 30 days before installing, upgrading, or closing systems. Delaware recognizes Class A/B/C operator credentials that align with federal standards; DNREC expects certificates, duty rosters, and monthly inspection logs to be produced during unannounced visits. Integrate these documents with the SOPs outlined in our Phase I ESA guide so third parties can evaluate compliance faster.

Leak Detection & Reporting Expectations

Delaware requires monthly monitoring capable of detecting a 0.2 gph leak (0.1 gph for precision tests) with 95% probability of detection and 5% false alarm. Automatic tank gauging must include annual functionality testing and 30-day records, while interstitial monitoring needs vacuum/pressure logs and sump photos. Suspected releases must be reported to DNREC within 24 hours via the environmental hotline, followed by a Release Confirmation Report that details free-product recovery, soil borings, and any temporary shutdown orders. Tie those reports back to LUST IDs to keep project files synchronized.

Financial Responsibility & Insurance

DNREC enforces the federal financial tiers: $1 million per occurrence for large marketers, $500,000 for smaller facilities, and $2 million aggregate for portfolios exceeding 100 tanks. Certificates of Financial Responsibility must list tank IDs, addresses, and retroactive dates that match DNREC’s facility file. If you rely on self-insurance, ensure the tangible-net-worth test is reviewed within 120 days of fiscal year close, and attach the CPA letter described in 40 CFR 280.95. Align policy effective dates with your UST registration anniversary to avoid lapses.

Cleanup Funding & Corrective Action

Delaware’s Storage Tank Assistance Fund (STAF), formerly FIRST, pays DNREC-approved contractors to remove tanks, excavate contaminated soil, and install monitoring wells for eligible petroleum releases. Residential heating-oil systems can access a separate Closure Assistance Program financed by the Hazardous Substance Cleanup Act (HSCA). Commercial operators that demonstrate compliance at the time of the release gain priority for Corrective Action Program cost share, especially near public supply wells in Kent and Sussex Counties. Use our cleanup cost guide to benchmark bids before submitting budgets to DNREC.

Actionable Tips for 2026

• Consolidate monitoring data: Store ATG printouts, sump photos, and interstitial pressure logs in cloud folders labeled by tank ID so DNREC can trace trends quickly.
• Schedule corrosion checks: Keep cathodic protection surveys on a 3-year cycle and test impressed-current systems every 60 days, logging rectifier readings.
• Coordinate with lenders: Share inspection histories alongside our due diligence checklist whenever properties change hands.
• Engage DNREC early: Email draft work plans before mobilization so TMS staff can flag data gaps and confirm STAF eligibility.

Official forms, guidance, and contractor listings are posted on the DNREC Tank Management portal; verify the latest circular letters before committing to schedules or procurement.