Most food trucks assume there is a building nearby. A restroom somewhere, a tap somewhere, a place to wash up. Plenty of operators do not have that. If you are parked at a trailhead, a job site, a rural school, a festival field or a community with no facilities at all, the vehicle has to carry everything with it.
We build that. A restroom with its own sink, toilet, plumbing, tanks and water heater, completely separate from the kitchen. It is not something most builders will take on, and it is the kind of requirement you either have or you do not.
A Truck We Built With a Toilet On Board
This is an 18ft French inspired sandwich truck we delivered to Denver. Walk through it and you can see how the restroom sits alongside a full commercial kitchen rather than replacing half of it.
Read the video transcript: Fire Suppression / Denver French Truck
The build list is worth reading, because it shows what you can still fit around a restroom in 18 feet:
| Area | What went in |
|---|---|
| Restroom | Toilet with a separate water system |
| Cook line | Range with a 24 inch griddle, two burners and an oven |
| Refrigeration | 36 inch refrigerated prep table, standup refrigerator, worktop freezer |
| Sinks | Hand wash sink, three compartment sink, mop sink |
| Water | 8 gallon water heater, 30 gallon fresh tank and 40 gallon grey tank, both mounted under the truck for easy filling |
| Service | 5 ft service window with awning door, self closing doors, bug screen |
| Finish | Stainless steel walls, aluminum diamond plate floor, LED lighting inside and out |
Look at the tanks. 30 gallons fresh, 40 gallons grey. The waste side is deliberately a third larger than the supply side, and that is not an accident, it is the thing that decides how long you can trade. More on that below.
Why the Plumbing Has to Be Completely Separate
This is the part that decides whether a build passes inspection, so it is worth being precise about.
Health codes treat food preparation water and restroom water as two different worlds. A handwash sink in a kitchen exists to keep food safe and cannot be shared with anything else. A restroom sink serves a room containing a toilet. Any shared supply, shared waste, or cross connection between the two creates a contamination path an inspector will fail you for, and rightly so.
So a restroom build is not a fixture added to an existing system. It is a parallel system: its own fresh tank, its own waste tank, its own pump, its own water heater and its own routing, kept physically separate from the kitchen throughout. Waste from a toilet is also handled differently from kitchen grey water, which affects tank choice and how the vehicle is serviced at the end of a shift.
That separation is why our Mugshots Coffee build in Missoula, Montana ends up with three independent water systems. The kitchen has one. The 4ft by 4ft restroom has one, with its own plumbing, its own tanks and its own water heater. And the espresso machine has a purified system of its own, because coffee equipment is fussy about water quality and scale in a way a dish sink is not.
People hear “add a toilet” and picture a fixture. It is closer to adding a second small building’s worth of plumbing to a vehicle that already has a full commercial kitchen in it.
What the Health Code Expects From the Kitchen Side
Even before the restroom, mobile water requirements are stricter than most first time buyers expect, and they are the reason a lot of older trucks cannot simply have a restroom added. Oregon’s health authority, in guidance dated January 2026, is a good representative example of where the bar sits:
- A minimum of 5 gallons dedicated to handwashing
- A minimum of 30 gallons, or twice the volume of the three compartment sink, whichever is greater, for warewashing
- A waste tank sized at least 15 percent larger than the fresh water tank
- All tanks integral to the unit, even where the unit connects to water and sewer on site
- Hot water delivered at 100 degrees Fahrenheit or higher, consistently
The same guidance lists handwashing setups that are no longer acceptable, and the list reads like an inventory of older used trucks: a 5 gallon catch bucket, gravity only systems, bladder containers, camping style handwash units, and foot pump systems. If you are buying used with a plan to add a restroom, check the existing handwash setup before you do anything else, because you may be rebuilding the kitchen water system too.
Requirements vary by state and county, so treat that as the shape of the rule rather than your specific numbers. Our permit guides cover what individual states ask for.
Tank Sizing Is the Decision That Bites
People underestimate how much water a restroom uses and how quickly waste capacity fills. Every flush and every handwash goes somewhere, and unlike a kitchen you cannot really ration it, because the whole point is that it is available when someone needs it.
Three things drive the sizing:
- Who is using it. Staff only on a two person truck is a completely different number from public access at a festival.
- Shift length. A four hour lunch service and a twelve hour event day are not the same build.
- Whether you can dump and refill mid shift. If there is nowhere to service the vehicle, everything has to be carried for the full day.
Waste capacity is what actually ends your day. You can sometimes top up fresh water from a hose. You cannot make waste capacity appear. That is why the Denver truck above runs 40 gallons of grey against 30 gallons of fresh rather than matching them, and why we size the waste side deliberately larger than a first guess. We would rather ask you awkward questions about volume up front than hand you a vehicle that fills by two in the afternoon.
Two practical notes from builds. Mounting the tanks under the vehicle, as on the Denver truck, keeps floor space for equipment and makes filling and dumping straightforward, which matters when you are doing it daily. And a bigger water heater is usually worth it on a restroom build, because you now have two demands on hot water instead of one.
The Space Trade, Honestly
A 4ft by 4ft restroom is sixteen square feet, plus the wall thickness around it and clearance for the door to open. On an 18ft truck that is a meaningful share of your working area, and it comes out of somewhere.
What it usually costs you is equipment line length or storage. The Denver truck worked because a sandwich and griddle menu has a compact cook line, so the restroom took space that a barbecue concept would have needed for a smoker. The same sixteen square feet is much harder to find on an equipment heavy build where an oven or smoker already dominates the layout. In those cases the honest answer is often a longer vehicle rather than a compromised one, and we will tell you that before you commit.
The other option worth considering is a second unit. For some operations a support trailer carrying the restroom and storage, towed alongside a compact food truck, works better than forcing everything into one box. It depends on where you park and whether you can manage two vehicles.
Built for Sites With No Facilities
The clearest case for this is a vehicle that works away from buildings by design.
We built an outreach van for the Carson Tahoe health system in Carson City, Nevada. A health system taking services out to people who cannot easily travel is, by definition, working somewhere without the infrastructure a clinic has. The vehicle has to be self sufficient, because there is often nothing to plug into and nowhere to send staff or visitors.
The same logic covers a lot of ground. Remote job sites. Rural events. Disaster response. Trailheads and parks. Anywhere the vehicle is the facility rather than an extension of one.
It also matters for staffing. An operator working a twelve hour event in a field with portable toilets a five minute walk away has a real problem when they are running a two person truck and one of them has to leave the line.
We Build for Institutions as Well as Food Businesses
Worth saying plainly, because neither of our sites has said it before. A good share of our work is for organisations rather than food entrepreneurs.
- Health systems. The Carson Tahoe outreach van, built for a hospital system working away from its buildings.
- School districts. We have delivered for the Lamar, Gadsden in Arizona and Canon City school systems, and for a Grand Junction school district as a school bus to food bus conversion. You can see more on our food trucks for schools and districts page.
- Community and outreach programs that need a vehicle to function independently of any site.
Institutional buyers usually arrive with a different set of questions than a first time food truck owner. Procurement timelines, accessibility, service life, and whether the vehicle can operate somewhere with no hookups at all. We are comfortable with all of that, including producing a documented specification you can put in front of a board rather than a one line price.
Questions We Will Ask You
You do not need answers to all of these before you call. Working through them is the job.
- Where will the vehicle park, and is there water, power or sewer there?
- Who uses the restroom, staff only or the public?
- How long is a typical shift, since that drives tank sizing more than anything else?
- Can you dump and refill during the day, or does everything have to be carried?
- Does the vehicle need to run while it is moving, or only when parked?
- What is the menu or the service, since that decides what space is left?
- Which jurisdiction will it be permitted in, because the water and waste numbers change?
Common Questions
Can a restroom be added to a truck I already own?
Sometimes, and it depends almost entirely on whether there is a place to put the tanks and whether the existing kitchen water system meets current requirements. On a newer truck with under mounted tanks and room to spare it is a real conversation. On an older unit with a marginal handwash setup you are often rebuilding the water system as well, and at that point a purpose built vehicle can be the cheaper answer. We will look at photos and tell you which one you are.
Does a restroom on board mean I do not need one at the site?
Not necessarily, and do not assume it. Whether an on board restroom satisfies a requirement for employee or public facilities is a local health department question, and the answer varies. Ask your jurisdiction directly before you spend money on the basis of it.
How much does it add?
Our trucks start around $55,000 and trailers around $40,000, with a typical 16ft build around $72,000 and a large 22ft build around $110,000. A restroom adds to that, and the amount depends on tank sizing, the water heater and how much structural work the layout needs. We quote it properly rather than guess, because the range between a compact staff restroom and a public facing one on a long shift is wide.
Is it accessible?
Accessibility requirements depend on your organisation, your funding source and how the vehicle is used, and they are not something to guess at. Tell us what standard you have to meet and we will build to it or tell you plainly if it cannot be met in the footprint you have in mind.
What is completed before delivery?
The vehicle is finished and tested before it leaves us, including the fire suppression inspection where the build calls for one. Local health and operating permits are issued by your jurisdiction, so those steps are yours.
Talk It Through
A restroom build is a specific requirement, and most builders will steer you away from it. Call or text 719-722-2537 and describe where the vehicle is going to work. We will tell you honestly whether an on board restroom is the right answer or whether there is a simpler way to solve it.
You can price the rest of the build with our build and cost calculator, or see more finished vehicles on our build videos page.
Zion Foodtrucks, 213 Aspen Garden Way Unit 2, Woodland Park, CO 80863. Around 500 builds delivered across the Mountain West.