Hazardous Materials Storage Program

The Santa Clara County Hazardous Materials Storage Ordinance (HMSO) is an essential part of keeping our community safe. Its purpose is to protect human and environmental health through prevention and control of unauthorized discharges of hazardous materials.


Santa Clara County Code of Ordinances, Title B, Division B11, Chapter XIII


The HMSO applies to any facility, which stores hazardous materials, in the cities of Los Altos Hills, Monte Sereno, and Saratoga, as well as all unincorporated areas of Santa Clara County (including Moffett Field, San Martin, and Stanford).

General Requirements

  • You must disclose your hazardous materials. This may be done by electronically submitting a Hazardous Materials Business Plan. If you do not have HMBP-threshold materials, a Hazardous Materials Registration Form may be submitted instead. Please see our electronic reporting​ page for more details.
  • Monitor hazardous materials storage areas in accordance with an approved monitoring plan.
  • Provide secondary containment for all hazardous materials.
  • Separate incompatible materials.
  • Post emergency response procedures.
  • Pay an annual invoice to keep your permit active.​​
  • Plan review and approval is required prior to constructing, retrofitting, upgrading or repairing any hazardous materials storage or handling system at any facility located in an unincorporated area of Santa Clara County (including Moffett Field, San Martin, and Stanford) or within the cities of Los Altos Hills, Monte Sereno, or Saratoga.  Please see https://hazmat.sccgov.org/programs-and-services/plan-review for additional details.

Forms & Documents


If your facility is subject to the Hazardous Materials Business Plan program, permit fees are based upon the number of HMBP-reportable materials you have. 

Frequently Asked Questions​​

Please view FAQs here.​​​​​

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