Department of Public Works
Hazardous Materials Underground Storage Permit (HMUSP)

All new sites must obtain a permit through the DPW Environmental Programs Division before installing tanks. All sites with underground storage tanks must have a current HMUSP. If a site has an un-permitted underground storage tank, it must be permitted before it is removed.

New Installation Application Forms


At least 4 sets of plans need to be submitted. Submitted plans should include the following:
  • Site plan to scale depicting the tank(s) and fill and piping sumps, type of hazardous material to be stored, piping layout (product/waste, vapor recovery (gasoline), tank vent, remote fill) and dispensers (if any), location of monitoring system panel, audible/visual alarms (if any), emergency fuel shutdown switch, building structures, streets (and cross street), utilities, and north arrow;
  • A detailed parts list which includes the manufacturer name, model number, and third party approval of equipment to be installed. The parts list should include (but not be limited to):
    • Double-walled tank, size and product to be stored;
    • Spill buckets; drop tube; overfill protection device(s) - Phase I Enhanced Vapor Recovery equipment (see Air Resources Board Executive Orders)
    • Sumps (fill and piping);
    • Double-walled piping (product, vent, vapor recovery, remote fill, flex) and sizes;ยท Penetration/bulkhead fittings/test boots;
    • Turbine (for pressurized systems);
    • Automatic Line Leak Detector (for pressurized systems);
    • Under dispenser containment (UDC);
    • Monitoring panel and alarm;
    • Monitoring sensors for tank interstitial, automatic tank gage and/or high level alarm (if any), fill and piping sump sensors, UDC sensors and vacuum sensors.
  • Detail drawing of each: All primary and secondary containment equipment which is designed to hold hazardous materials (tanks, sumps, penetration fittings, piping, UDC) must be labeled as being product tight.
  • Tank details should show the parts listed above at a minimum.
All construction must conform to the requirements of the California Health & Safety Code (HSC) and California Code of Regulations (CCR) as well as local fire and building and safety codes.

When construction is completed

The CERTIFICATION OF INSTALLATION / MODIFICATION form must be submitted electronically to the CERS Business Portal before the UST system is put into service.

Tank tightness testing, line test results, results of enhanced leak detection or other approved method to satisfy requirements of the HSC/CCR, secondary containment testing results, monitoring system certification and line leak detector certification, must be submitted directly to DPW EPD before the UST system is put into service.
Managed by the Los Angeles County Public Works, Environmental Programs Division
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