A bathroom is the most requested feature in a camper van and the first thing struck off the plan once people see the arithmetic. It takes about nine square feet out of roughly fifty-two, it needs a second tank to catch what comes out of the first, and it holds fewer showers than anybody expects. Sometimes it is obviously worth it. More often it is not, and here is how to tell which you are.
What a bathroom costs in money and floor
A combined wet bath adds $3,000 to $6,500 to a professional build, and takes about nine square feet. The money is the smaller half of the price. The floor area is the real cost, and it comes out of the galley, the garage or the seating, because there is nowhere else in a van for it to come from.
Nine square feet sounds small until you put it against what you have. Mercedes publishes 374 cubic feet of cargo volume in a 144 inch high roof Sprinter and a 79 inch standing height, which is about 57 square feet of floor before the wall build and about 52 after it. A 170 inch gives about 68. A 3ft by 3ft enclosure is therefore 17% of a short van and 13% of a long one, taken permanently, from the middle of the plan.
| Option | Build cost | Floor space | What you get |
|---|---|---|---|
| No bathroom | $0 | None | Gyms, campgrounds, public facilities |
| Cassette toilet in a cupboard | $400 to $1,200 | 2 sq ft | A toilet, no shower |
| Composting toilet | $1,000 to $2,000 | 2 to 3 sq ft | A toilet, no black tank to dump |
| Outdoor shower | $600 to $1,500 | Almost none | A shower, weather and privacy permitting |
| Combined wet bath | $3,000 to $6,500 | 9 sq ft | Toilet and indoor shower in one room |
| Separate shower and toilet | $6,000 to $12,000 | 14 sq ft | Rare below a 170in wheelbase |
Against a median starting price of $58,000 across the 46 US shops in our directory that publish pricing, a wet bath is roughly a tenth of the build. That is not the number that should decide it.
The water arithmetic that decides everything
Here is the question no guide in this category answers: how many showers does a tank hold? It is answerable, and the answer changes what people decide.
The EPA sets the federal maximum showerhead flow rate at 2.5 gallons per minute, with the WaterSense specification at 2.0. Van showers usually run a low-flow head, so 2.0 is the fair number to plan against and 2.5 is the ceiling. Multiply by how long you actually stand under it.
| Shower length | At 2.0 gpm | At 2.5 gpm | Showers per 30 gallon tank |
|---|---|---|---|
| 2 minutes, navy shower | 4 gal | 5 gal | 6 to 7 |
| 4 minutes | 8 gal | 10 gal | 3 to 4 |
| 6 minutes | 12 gal | 15 gal | 2 to 3 |
| 10 minutes, at home | 20 gal | 25 gal | 1 |
So a 30 gallon tank is two comfortable showers, or four disciplined ones, and then you are looking for water. That is the whole reason van dwellers talk about navy showers, and it is not frugality for its own sake. It is the difference between refilling weekly and refilling every third day.
For scale, the EPA puts showering at nearly 17% of residential indoor water use, roughly 40 gallons a day for an average family. A van carries less than one day of that household behaviour in its entire fresh tank, which is the clearest way to see why a van shower is a different activity from a house shower rather than a smaller one. Hot water is the second limit and it arrives sooner than the tank does: a typical van water heater holds two to six gallons, so a long shower runs cold well before it runs dry.
Then there is the other tank. Everything that goes down a shower drain has to be caught and dumped somewhere legal, so a grey tank has to roughly match the fresh one. Water weighs 8.34lb per gallon, which puts 30 gallons at about 250lb, and a fresh and grey pair at full at about 500lb. On a van where payload is already the binding constraint, that is a serious commitment to make for a shower.
The knock-on effect is where you can be and for how long. A shower roughly quadruples how often you need a service point, which narrows where you can realistically park for a stretch from anywhere with a view to anywhere within a tank of a dump station.
Why a bathroom forces a redesign
A wet bath is not a box you place into a finished layout. It is a set of constraints that the rest of the van has to be drawn around, which is why the same shop will quote a shower at $4,000 in one van and decline to fit one in another.
It needs plumbing in and plumbing out, which means both tanks and a route between them, and both tanks want to be low and between the axles for handling reasons. It needs mechanical ventilation, because a sealed damp room in an insulated metal box does exactly what you would expect. It needs a door that opens somewhere, in a vehicle where every square foot of door swing is contested.
It is also a standards question rather than a joinery one. RVIA's adopted standards, built on NFPA 1192, cover how plumbing and fuel-burning appliances such as water heaters are installed, not just which parts are used. That matters beyond compliance, because certification affects insurance and resale and a shower is often the system that pushes a build into needing it properly documented.
All of which is why the bathroom question sits second in the order layout decisions have to be made in, immediately after the bed. Deciding it late is the most common cause of a full redraw.
The options, from a cupboard to a dry bath
There are five setups that turn up repeatedly, and they are not variations on a theme. They solve different problems and they cost different amounts of the thing you are short of.
Cassette or composting toilet in a cupboard
Two square feet, a door, and no shower. A cassette has a removable holding tank you empty at a dump point or a suitable toilet. A composting unit separates liquids from solids, needs no black tank at all, and asks you to be comfortable with the maintenance. Both are the highest-value two square feet in van design.
| Toilet | Cost | Emptying | Drawback |
|---|---|---|---|
| Portable, bucket style | $100 to $250 | Anywhere suitable, every few days | Small capacity, no ventilation |
| Cassette, built in | $400 to $1,200 | Dump point or toilet, every 3 to 5 days | You carry the cassette to the point |
| Composting | $1,000 to $2,000 | Liquids often, solids every few weeks | Bulkier, and the maintenance is hands-on |
| Dry flush | $600 to $1,200 | Sealed cartridge, no liquids to dump | Ongoing cost of the cartridges |
Outdoor shower
A hose fitting on the exterior, usually fed from the same hot water system, with a pop-up tent or a rear door curtain for privacy. It costs almost no interior floor at all. It works for two thirds of the year in most of the country and it depends entirely on having somewhere private to stand, which is a rural luxury.
Hidden or retractable shower
A shower pan built into the floor of the galley or a hallway, with a curtain track above it and a drain that is normally covered. It buys a wet shower without a dedicated room, and it costs you a wet floor in the middle of your kitchen. Genuinely clever, and used less often than the photographs suggest.
Combined wet bath
One water-tight room, toilet and shower sharing the space. The most space-efficient way to have both indoors and the option most people mean when they say bathroom. Nine square feet, $3,000 to $6,500 fitted.
Separate shower and toilet
Two rooms. Fourteen square feet and $6,000 to $12,000, which puts it out of reach below a 170 inch wheelbase and into the territory of shops that engineer rather than configure.
What most full-timers actually end up with
Two combinations cover the large majority of full-time vans on the road, and neither of them includes an indoor shower. That is worth knowing before you spend nine square feet on one.
A cassette or composting toilet plus a gym membership. Around $800 to $2,000 all in, and two square feet. The gym is not a compromise, it is a genuinely better solution to the shower problem: unlimited hot water, no grey tank, no drying, no freezing, and a facility in every town you pass through. At roughly $25 a month it is one of the smaller lines in what running a van actually costs, and many full-timers keep it permanently even after building a shower.
A toilet plus an outdoor shower. Around $1,500 to $3,000. It works excellently from April to October, and it stops working in a cold snap or anywhere with neighbours. People who choose this are usually people who follow good weather, and it suits them very well.
The pattern is that both of these push the shower outside the van, either onto a facility or onto the weather. The wet bath is the only option that insists on solving it inside, and that insistence is what costs nine square feet.
The fork nobody names: convert, or buy a factory van
Search this subject and half the results are conversions and half are factory Class B motorhomes with bathrooms already in them. That is not a search engine failing to understand you. It is an accurate reflection of the fact that most people asking this question have not yet decided which of the two they are buying, and the bathroom is often the reason.
Factory Class B vans arrive with a wet bath, a black tank, a grey tank and a certified plumbing system, all designed together at volume. That is genuinely the cheapest route to an indoor shower, and if a bathroom is your first requirement it deserves a serious look before you commission anything.
| Factory Class B with wet bath | Conversion with wet bath | |
|---|---|---|
| Bathroom cost | Included in the base price | $3,000 to $6,500 on top |
| Layout around it | Fixed, and drawn for the tanks | Yours, but constrained by them |
| Tank capacity | Sized for the bathroom | Sized for whatever you specify |
| Garage or gear space | Usually minimal | Whatever survives the bathroom |
| Winterisation | Varies, often a factory package | Specified at build, if you ask |
The reason people still convert is everything else in that table. A factory van gives you the bathroom and takes the layout, the garage and usually the off-grid capacity, and those are the things full-timers care about most. Which way that trade falls is the whole of the conversion against factory RV decision, and the bathroom is simply the feature that forces people to make it consciously.
When a wet bath genuinely earns its space
- You travel in winter or in cold climates. Outdoor showering stops being viable and the gym is a long drive at 7am in the snow.
- You park in towns rather than on public land. Privacy for an outdoor shower is a rural luxury, and van dwellers who work in cities do not have it.
- Medical or accessibility needs. This is not a preference question and the trade-off analysis above does not apply to it.
- You have children. Frequency of use rises steeply, and a four-year-old at a truck stop shower at 10pm is a poor plan. It is one of the clearest differences in how a family van is specified.
- You have a 170in or 159in wheelbase. On a shorter van, nine square feet is 17% of the floor and the compromises elsewhere are usually worse than going without.
If two or more of those apply, build it. If none of them do, the money and the floor buy considerably more comfort spent elsewhere in the van.
Winter is where van bathrooms fail
Nobody in this category writes about freezing, and freezing is what actually ends the use of most van bathrooms. It is worth understanding the mechanism, because the failure is progressive rather than sudden.
The vulnerable parts are the ones outside the insulated envelope. Underslung tanks freeze first, then the exposed pipe runs to them, then the grey tank outlet, which is usually the very last thing anyone thinks about and the first thing that blocks. A frozen grey outlet with a full tank means you cannot shower, cannot wash up and cannot dump until it thaws.
The fixes are known and they cost money at build time rather than later. Tanks inside the insulated space rather than underslung. Heated tank pads and heated pipe runs. A heater sized to keep the whole van above freezing overnight rather than just to make the living area comfortable, which is a bigger unit than most people specify. All of that is straightforward to design in and awkward to add, so it belongs in the same conversation as the shower rather than a season later.
This is also the honest counterargument to the case above. Winter is the strongest reason to want an indoor shower, and winter is the condition under which an indoor shower is hardest to keep working. Both things are true, and a van built for winter showering is a more expensive van than one built for summer showering.
The daily realities nobody photographs
Wet bath means wet bath. Every surface in that room gets wet each time you shower, including the toilet, the seat, the paper and whatever you left on the shelf. That is what the word describes and it consistently surprises people who have only seen the photographs.
Drying it is a daily job. Squeegee the walls, wipe the seat, leave the fan running, prop the door. Skip it for a fortnight in autumn and the room becomes the place mould starts, and from there it moves into the wall cavity behind it where you cannot see it and cannot easily reach it.
There is also a storage cost that never appears in the budget. A wet room cannot store anything, so the towels, the toiletries and the toilet paper all live somewhere else and get carried in and out. In a van, nine square feet that cannot hold anything is a genuine loss, and it is the reason some builds put a shelf outside the door and call it part of the bathroom.
None of this is an argument against building one. It is an argument for knowing what you are choosing, because the people who are happiest with their wet baths are the ones who expected all of the above and built the van around it rather than the ones who saw a photograph of a tiled cubicle. Getting that right is largely about which shop drew the plan, and it shows up clearly in how the systems in a quote are broken down.
Key takeaways
- A wet bath costs $3,000 to $6,500 and about nine square feet, which is 17% of the usable floor in a 144in van.
- A 30 gallon tank is two comfortable showers, at the EPA's 2.0 gpm WaterSense rate over six minutes.
- A grey tank has to match the fresh one, so a shower commits about 500lb of payload to water at full.
- It forces a redesign because it needs two tanks, ventilation, a door swing and a certified plumbing installation.
- Most full-timers end up with a toilet in a cupboard plus either a gym membership or an outdoor shower.
- Winter travel, urban parking, accessibility and children are the cases where a wet bath clearly wins.
- Freezing ends more van showers than anything else, and the grey outlet blocks first.
- Everything in a wet bath gets wet, it stores nothing, and drying it daily is what prevents mould.