Food Truck Plumbing Requirements in California: Sinks, Water Tanks, and the Commissary Rule

Published by Clément Lacaille, Tech-Bharat · Updated September 7, 2026 · How we research

If you are building out a food truck in California, the first thing worth knowing is that the plumbing rules you have to satisfy are not in the plumbing code. A mobile food facility (MFF, the term the state actually uses) is regulated under the California Retail Food Code — CalCode, found in Division 104, Part 7 of the Health and Safety Code — and enforced by your county environmental health department, not by a building department doing a plumbing inspection. That distinction matters, because CalCode specifies sink dimensions, tank capacities, and water temperatures as hard numbers in statute, and because the one part of your operation that is governed by the California Plumbing Code — the fill-and-dump station at your commissary — is the part most operators discover late and budget for badly.

The sinks CalCode requires on board

Two separate sink systems are required on any truck selling nonprepackaged food, and inspectors treat them as non-negotiable.

• A dedicated handwashing sink, at least 9 inches by 9 inches and 5 inches deep, easily accessible to food employees (HSC 114311). It must be separate from the warewashing sink, and separated either by a metal splashguard at least 6 inches high running the full depth of the drainboard, or by 24 inches or more of clear distance.
• A three-compartment warewashing sink with two integral metal drainboards for any truck that cooks, blends, or otherwise prepares nonprepackaged food (HSC 114313). Each compartment must be at least 12" x 12" x 10" deep, or 10" x 14" x 10", and large enough to accommodate your largest utensil. The exemptions are narrow — steamed hot dogs, tamales served in their original wrapper, and similar operations that keep spare utensils and clean everything at the commissary daily.

Trucks handling only whole produce or bulk-dispensing nonpotentially hazardous beverages fall outside the handwash-sink requirement, and some unenclosed beverage operations can use a two- or one-compartment alternative. Everyone else builds all four basins.

Hot water is a capacity requirement, not just a temperature

CalCode sets both. HSC 114325 requires a water heater or instantaneous heater capable of heating water to at least 120°F, and specifically requires a minimum 4-gallon water heater on any truck that has a warewashing sink. Only a truck whose water is used purely for handwashing can drop to a half-gallon or instantaneous unit heating to 100°F. On the delivery side, HSC 114217 requires the water system to supply at least one gallon per minute to each sink basin — which is why a marginal 12V pump is a recurring plan-check problem.

In practice, county inspectors cite the pressurized-hot-water requirement constantly: Sonoma County's published explanation of mobile food facility violations pairs 120°F for warewashing with 100°F at the handwash sink and treats a failed heater as a major violation. If you are choosing between a small tank and an on-demand unit, the same trade-offs apply as in a building — see our comparison of tank versus tankless water heaters, keeping in mind the statutory 4-gallon floor for warewashing trucks.

Fresh water tank: 5, 15, or 25 gallons minimum

HSC 114217 sets the floors, and they stack rather than substitute:

• 5 gallons reserved exclusively for handwashing, on every mobile food facility. Water for any other purpose is in addition to that 5 gallons.
• 25 gallons for food preparation and warewashing.
• 15 gallons where the operation is limited to what CalCode defines separately as limited food preparation.

The tank itself has construction rules too: enclosed from the filling inlet to the discharge outlet and able to drain completely (HSC 114219), fitted with a top access port that is flanged upward at least half an inch with a gasketed, securable cover (HSC 114221), and — the detail that trips up DIY builds — a potable water inlet three-quarters of an inch inner diameter or smaller, with a hose connection of a size or type that prevents its use for any other service (HSC 114231). That is a deliberate anti-cross-connection rule: your fresh-water fitting must be physically impossible to confuse with your waste fitting. HSC 114235 puts the same obligation on the operator, requiring the tank, pump, and hoses to be run so that backflow and contamination cannot occur — the mobile equivalent of the backflow protection a fixed commercial kitchen has to test annually.

Greywater tank: 50% larger than fresh, by statute

This is the number people get wrong most often. HSC 114240 requires wastewater tanks to have a minimum capacity that is 50 percent greater than the potable water tanks, and never less than 7.5 gallons. On top of that:

• Where potable water is used to prepare food or beverages, add wastewater capacity equal to at least 15 percent of the water supply.
• Where ice is used for storage, display, or service, add a holding tank equal to one-third of the ice cabinet volume for melt drainage.
• The wastewater tank must have a shut-off valve, and more capacity can be required if your production is likely to exceed the tank.

Worked through: a truck with the standard 25-gallon prep-and-warewash tank plus the mandatory 5 gallons for handwashing is carrying 30 gallons of fresh water, so the wastewater tank has to be at least 45 gallons before the food-preparation and ice-melt add-ons. Sizing the greywater tank to match the fresh tank — the instinct most people have — fails plan check on its face.

The commissary requirement, and why it is really a plumbing question

HSC 114295 requires mobile food facilities to operate in conjunction with a commissary, mobile support unit, or other facility approved by the enforcement agency, with narrow exceptions for community events and certified mobile farmers' markets. HSC 114297 requires the truck to be cleaned and serviced at least once per operating day. And HSC 114326 spells out what the commissary has to physically provide: potable water for filling tanks, hot and cold water under pressure for cleaning the unit, facilities for disposing of liquid waste and garbage, overhead protection except at the water-loading and sewage-discharge areas, and drainage to an approved wastewater system.

Emptying the greywater tank anywhere else is not a grey area. HSC 114241(c) requires sewage and liquid waste to be removed at an approved waste servicing area or by an approved sewage transport vehicle, and California stormwater programs are blunt that discharging anything other than rain to a gutter or storm drain — including clean potable water — violates federal, state, and local law, with civil penalties attached. Wash water from a truck carries fats, oils, grease, and detergents straight to a creek if it hits a storm inlet.

Where a licensed plumber actually comes in

Nothing above requires a plumbing permit for the truck itself. The commissary side does. Building a compliant servicing point on a fixed site is ordinary commercial plumbing under the California Plumbing Code — the same body of rules behind commercial kitchen plumbing requirements — and typically involves some combination of:

• A dump receptor connected to the sanitary sewer, sized and trapped for the discharge, on a curbed, sloped, drained pad.
• A potable fill station — hot and cold under pressure — with backflow protection appropriate to the hazard, since a hose that can reach a waste area is a cross-connection risk.
• Grease handling, because commissary wash water is FOG-laden. If you are the property owner, review grease interceptor requirements and costs and your local sewer agency's rules before assuming an existing trap covers added truck servicing.

Cost depends almost entirely on how far the work sits from existing sewer and water. Adding a hose bibb with backflow protection and a receptor next to lines that already exist commonly lands in the $600-$2,500 range; trenching a new sanitary connection across a yard, plus a curbed and drained pad, more realistically runs $2,500-$8,000 or more, and a new or upgraded in-ground grease interceptor is its own line item that can reach $7,000-$20,000+. These are broad planning ranges, not quotes — the scope is site-specific and worth pricing before you sign a commissary lease. If you are renting the space, our guide to landlord versus tenant responsibility for commercial plumbing repairs is worth reading before you pay for someone else's infrastructure.

Permits, inspection, and what gets flagged

Health permits are issued county by county, and there is no automatic statewide reciprocity — operating in a second county generally means a second application, fee, and inspection there, with only limited county-to-county arrangements in a few places. Fees are set by each county's board of supervisors and revised regularly, so get the current schedule from the county rather than a blog. The sequence is plan check first, build second: submitting drawings showing sink dimensions, tank capacities, water heater, and your commissary agreement before fabrication is far cheaper than cutting a stainless counter twice.

The failures inspectors write up most are mundane: a handwash sink blocked or missing hot water, a greywater tank undersized or already full mid-service, a water heater that cannot hold 120°F under load, and missing or improper commissary servicing records. None of these are exotic engineering problems — they are the consequence of a build that was designed to the truck's floor space instead of to the statute.

Worth noting for anyone who assumes mobile means riskier: a 2015 analysis by Angela C. Erickson published in Food Protection Trends examined 194,687 inspections across 34,396 establishments in seven large U.S. cities and found that mobile food vendors averaged fewer violations than restaurants in six of them, with Seattle roughly equal (Erickson 2015). Regulators have also studied the California-specific picture directly: Faw and Tuttle's 2014 Journal of Environmental Health report on the California EHS-Net study of mobile food trucks focused precisely on risk factors and the practical difficulty of inspecting a facility that moves (Faw & Tuttle 2014). Compliance on a truck is achievable — it just has to be designed in.

Keeping the system working

Ongoing maintenance is short but unforgiving. Sanitize the potable tank on a schedule and drain it completely rather than topping off stale water; use a drinking-water-rated hose kept off the ground and never interchangeable with the waste hose; flush the wastewater tank at each servicing rather than only when it smells; descale an on-demand heater on hard-water routes, the same way you would descale a tankless unit at home; and in inland and mountain counties, winterize the plumbing when the truck sits — a split pump housing or cracked fitting is a cancelled service day, not just a repair. Grease discipline matters too: what causes FOG-clogged kitchen drains in a restaurant does the same thing to a commissary line fed by a dozen trucks, which is why busy servicing yards end up on a commercial hydro jetting schedule.

Building or upgrading a commissary servicing point in Los Angeles, Oakland, Sacramento or elsewhere in California? That part is real, permitted plumbing work — see our overview of California plumbing permits, then request a free quote and have a licensed local plumber scope the sewer connection, fill station, and backflow protection before your health inspection is scheduled.

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