Los Angeles County Hydrostatic Testing

Cylinder pressure testing for dry chemical, CO2, water and Class K extinguishers

Which extinguishers are due, and when

A hydrostatic test checks that an extinguisher's shell can still safely hold pressure. NFPA 10 sets the interval by type:

• Dry chemical: every 12 years.
• CO2: every 5 years.
• Water: every 5 years.
• Wet chemical (Class K): every 5 years.

Most buildings have a mix. A restaurant might keep a Class K unit by the cooking line on the 5-year cycle and dry chemical units by the exits on the 12-year cycle, so each cylinder's own test date has to be checked. Stored-pressure dry chemical units also get a 6-year internal maintenance (a teardown) between hydro tests. Both are separate from the yearly maintenance recorded on the tag, which you can read about on our fire extinguisher annual certification page.

What happens to a cylinder during the test

The technician empties the extinguisher and takes the valve off. The shell is then checked inside and out for corrosion, dents and other damage. Next it's filled with water, brought up to its rated test pressure and watched for leaks, bulging or distortion. A cylinder that passes is dried, recharged, put back together and labeled with the test date. One that fails is taken out of service and replaced. If a unit has simply been discharged or lost pressure, it may only need a fire extinguisher refill.

Who can do the work

California requires extinguisher service to be done by a firm and technician licensed by the State Fire Marshal under Title 19. Our California work is performed by Hedrick Fire Protection, which holds C-16 (fire protection) and C-10 (electrical) contractor licenses and is State Fire Marshal licensed under Title 19 for extinguisher service and for water-based system service.

Your local fire office

It depends on your address. In unincorporated areas and County Fire's contract cities, the Los Angeles County Fire Department's Fire Prevention Division does annual business inspections. The City of Los Angeles has its own department (LAFD), and some cities, Burbank among them, run their own fire prevention bureaus. The county's fire code is Title 32 of the County Code, which is its set of amendments to the 2022 California Fire Code; extinguishers fall under CFC Section 906. Confirm the current edition with your fire office before an inspection.

To book hydrostatic testing in Los Angeles County, call (213) 568-0188 or email socal@1profire.com. It helps to have a count of your extinguishers by type, plus the test dates on their labels if you can read them.

More on extinguishers here: our fire extinguisher service and fire extinguisher training pages, and the Los Angeles County hub. Nearby city pages: hydrostatic testing in Burbank, hydrostatic testing in Glendale and hydrostatic testing in Downey. For a job in the county, read how we handled bilingual extinguisher service for a La Puente restaurant.

Common questions about extinguisher hydro tests

Is a hydrostatic test the same as the annual inspection?

No. Annual maintenance happens every year and goes on the tag. A hydrostatic test is a pressure test of the cylinder, due every 5 or 12 years depending on the extinguisher type.

Does an extinguisher that was never used still need testing?

Yes. The interval counts from the last test date whether or not the unit was ever discharged.

My building is in the City of Los Angeles. Is County Fire my fire office?

Usually not. Inside city limits the fire department is LAFD, so check its requirements for your building.