Start with the date on the cylinder
Every extinguisher carries the date of its last hydrostatic test. Find that first. On a dry chemical unit it is usually a label on the cylinder, and on a CO2 unit the date is stamped into the metal near the top, so you can check a whole floor in a few minutes without opening anything. Then compare it to the schedule below.
Paramount callers have asked us this: do extinguishers over 12 years old need hydrostatic testing? For dry chemical units, yes. Twelve years after the last test (or after manufacture, if the cylinder has never been tested), the unit is due, and it should not be tagged as serviced until the test is done.
Which units are due, and how often
The schedule comes from NFPA 10 and California's Title 19 rules. It depends on what's inside the cylinder.
- Dry chemical: hydrostatic test every 12 years. Stored-pressure models also get a 6-year internal teardown.
- CO2: every 5 years.
- Water: every 5 years.
- Wet chemical (Class K): every 5 years.
Annual maintenance still happens every year. A hydro year is the same annual visit with extra work added for the units that are due, so if your dates line up, both happen on one service call. If you only need the yearly tag, see annual fire extinguisher certification in Paramount. Kitchens with a hood suppression system also need a Class K extinguisher, and that unit runs on the 5-year cycle; our Paramount kitchen fire service page covers the hood system itself.
What happens during the test
The test checks the cylinder shell. The technician empties the extinguisher, takes out the valve, and looks over the inside and outside of the shell for corrosion, dents and damaged threads. Next the cylinder is filled with water and pressurized to its rated test pressure inside a protective cage. Then the technician watches for leaks, bulges or permanent distortion.
A cylinder that passes is dried, recharged and marked with its new test date. A cylinder that fails is condemned. It can't be refilled. You replace it. Units that only need recharging after use go through extinguisher refill, which is a separate service.
Heavy is not the same as working
One Paramount caller told us about an extinguisher that felt full and charged but didn't discharge during an actual fire. Weight only proves the agent is there. It tells you nothing about a clogged hose, a corroded valve, caked powder or a weakened shell, which is why NFPA 10 adds an annual check, a 6-year teardown for stored-pressure dry chemical units and the hydrostatic test on top of the monthly look you do yourself.
Old extinguishers raise a related question. We've been asked whether units from 1984 or earlier can still be serviced. Some can't. The technician reads the manufacture date and the nameplate and tells you whether that unit can be tested or should be replaced.
Who inspects in Paramount, and who does the testing
Fire service in Paramount comes from the Los Angeles County Fire Department, and the city is part of the county's consolidated fire protection district. Business fire inspections are handled by the department's Fire Prevention Division. For Paramount, that's the East Regional Office at 19030 Pioneer Blvd in Cerritos, (562) 860-8014.
The city's fire code is the Los Angeles County Fire Code, adopted by reference in Paramount Municipal Code section 8.08.010 with no local changes listed for extinguishers, and the city has also adopted the 2025 California Fire Code, where Section 906 covers portable extinguishers. If an inspector flags an out-of-date cylinder, those are the rules behind it.
In California, extinguisher service has to be done by a firm and technician licensed by the State Fire Marshal. Our California work is performed by Hedrick Fire Protection, which holds C-16 and C-10 contractor licenses and is licensed by the State Fire Marshal under Title 19 for portable extinguisher service.
Most of the calls we get from Paramount are about extinguishers. Some come with a fire department notice and a deadline the next day. If that's you, say so on the first call. For everything else we do in the city, start at our Paramount fire protection page or read about fire extinguisher service in Paramount.
Hydrostatic testing questions from Paramount
Do extinguishers over 12 years old need hydrostatic testing?
Dry chemical units do, every 12 years. CO2, water and Class K wet chemical units come due sooner, every 5 years.
Are extinguishers from 1984 or older still serviceable?
Sometimes not. A technician checks the manufacture date and nameplate and tells you whether the unit can be tested or should be replaced.
Will expired cylinders add to the cost?
Yes. A unit that's due needs the test on top of its annual service, and one that fails has to be replaced. Ask for a count of units due when you request a quote.
Who inspects extinguishers at Paramount businesses?
The Los Angeles County Fire Department's Fire Prevention Division, through its East Regional Office in Cerritos.
Do you service the Paramount area?
Yes. Paramount is one of our listed service areas.
Testing extinguishers outside the city? See hydrostatic testing in Los Angeles County and Orange County.
To schedule hydrostatic testing in Paramount, call (213) 568-0188 or email socal@1profire.com. Have your cylinder count and test dates ready.