By Clayton Houser – Professional van builder (50+ full builds)
Clayton explains why van plumbing stops feeling “simple” once you live with it – then shows how he plans showers, tanks, hot water, and drain speed so the system feels normal, works daily, and stays serviceable without tearing the van apart.
This is the eighth article in Clayton's Van Build series - you can view the series homepage here.
Plumbing is one of those systems people assume will be simple until they live with it. A slow sink, a shower that backs up, or a leak you can’t reach turns “minor” decisions into daily frustration.
My plumbing philosophy is pretty consistent. I want it to feel normal. I want drains that actually drain, water pressure that feels usable, and a setup I can service without tearing the van apart.
Plumbing Starts With One Honest Question
Do you want a shower, or just a sink?
Most plumbing decisions get easier once you answer that. A sink-only build can be straightforward. A shower changes the whole system – tank sizing, hot water, drain design, and where everything lives.
For me, showers matter enough that they show up early in layout. Once the bed decision is made, shower and bathroom decisions are right behind it because they’re big space claims and big system drivers.
Why I’m Pro-Shower
I’ve lived the “no shower” idea. In theory, it sounds fine – gyms, campgrounds, whatever. In reality, I didn’t use the gym showers, and I never found campground showers I actually wanted to use. I’ve also had an outdoor shower, and where I camped it often turned into either a mess or a privacy problem.
After that, I stopped treating a shower as optional. If I’m going to build a van I’ll actually want to live in, I need an indoor shower, and I plan the plumbing, tanks, and hot water around that from the start.
I Plumb It Like a House
Drain speed matters more than people think
There’s almost nothing I hate more than a slow drain, especially in a shower. I’ve used inch-and-a-half drains because I want sinks and showers to drain like a normal home. That’s a big reason I avoid the typical RV drain kit approach.
A lot of RV drain kits rely on small expandable hose. That can be fine with tiny RV sinks and low flow, but many of my builds use real sinks and faucets. If your drain can’t keep up, you feel it every day.
Sequence Matters
I like to plumb while the van is still open
Plumbing is easier when access is good. Once walls and cabinets are finished, it gets harder to route lines, mount tanks, and fix mistakes cleanly.
One workflow I’ve used is setting the shower and the sink base after the floor is in, then plumbing behind the cabinets while everything is open. I’d rather do that work early rather than “finish the van” and then realize I buried something important.
Build It So You Can Fix It
Even good plumbing needs attention. You’ll change things. You’ll add something. A fitting will eventually need service. I plan for that.
For connections, I’ve used PEX with quick disconnects instead of crimp-on connections because it makes modifications and repairs much more realistic. If a repair requires cutting everything apart, people avoid fixing things until they become bigger problems.
I’ve also used an accumulator tank with the pump because it helps water delivery feel smoother and less chattery.
Tanks and Plumbing Layout
One tank, or split by side, depending on the footprint
Tank layout is partly about your needs and partly about your floor plan.
If the shower and sink are on opposite sides, I’ve split tanks by side so the system stays clean. In one example, that looks like one tank for the shower side and one for the sink side. It keeps lines shorter and layout more intuitive.
I’ve also used ball valves and quick attachments so draining and filling is practical. If someone is dispersed camping, they can drain easily. If they’re somewhere structured, they can hook up and fill cleanly.
Fresh water sizing
This is how I’ve commonly sized fresh water based on real use:
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If the van has a shower, I’ve typically run around a 30-gallon fresh tank.
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If it’s sink-only, I’ve used smaller tanks – around the low-20s gallon range.
The point is not a perfect number. The point is matching capacity to how the van is actually used.
Water Heaters
There are a lot of options for water heaters and, again, it depends on how you will actually use your van. People tend to love having large water heaters. If you need that, Vanlife Outfitters sells some great options. Personally, I prefer smaller water heaters with a water-efficient shower head, but that’s my personal preference.
I’ve seen tankless units used in camper vans, but I haven’t installed them myself. Exhaust heat and venting are real constraints in a small space, and I’m not interested in creating problems to solve problems. They can work, but I never thought they were worth it.
Showers That Actually Work in a Van
A shower can look good on paper and still feel terrible in real life.
I’ve used showers that felt too tight, where you’re basically stepping in and out to wash different parts of your body. That’s one reason I’ve liked shower setups that create more usable space while you’re actually using them.
One of the roomiest showers I’ve ever had was a fold-down shower with a curtain. The curtain matters. Curtains give you space to move and don’t box you in the way some doors do. Slider doors especially can make a shower feel smaller than it already is.
The takeaway is simple. If you’re going to give up space for a shower, make sure it’s a shower you’ll actually use comfortably.
Toilets in Tight Footprints
Sometimes you have to compromise on “ideal” to make a camper workable for you. In smaller vans, bathroom privacy can be hard to achieve the way you might want. I’ve done layouts where the shower is built into a cabinet and the toilet slides out when needed because there wasn’t room for a bigger, more private setup in that footprint.
I’m not saying everyone has to make that tradeoff. I’m saying it can be a realistic compromise when space is limited and the priority is still having an indoor shower and a workable bathroom routine. The point is to be honest about what your footprint can support and choose a bathroom approach you’ll actually use, not just one that looks good on paper.
What Comes Next
Once plumbing is planned around real usage and built with serviceability in mind, the next step is making sure the rest of your systems follow the same logic – clean layout, logical grouping, and access for future changes. That mindset carries into electrical and everything else you build into the garage space.
Frequently Asked Questions About Van Plumbing
1. How do I start planning my camper van plumbing?
Start by deciding if you’re building for a shower or just a sink. A shower changes everything – fresh water capacity, gray tank planning, hot water needs, and how much you care about fast drains.
2. What drain size should I use for a camper van sink and shower?
I plumb drains like a house because I can’t stand slow drains or standing in water. I use 1½-inch plumbing so sinks and showers drain fast and feel normal, instead of RV plumbing kits that use smaller sizes.
3. Are RV drain kits okay for a camper van build?
A lot of people use them, but they’re usually small and don’t drain very fast. If you’re running a real kitchen sink and faucet with decent pressure, those small drain setups can back up quickly.
4. How much fresh water do I need in a camper van?
My rule of thumb: about 30 gallons if the van has a shower. If it’s sink-only, I’ve used smaller tanks that are more in the 22–24 gallon range.
5. How do I route camper van plumbing if my shower and sink are on opposite sides?
If the sink and shower are on opposite sides, I’ve split the system by side to keep routing clean. I’ll usually put more capacity on the shower side and less on the sink side (for example, 20 gallons shower side and 16 gallons sink side).
6. What plumbing fittings make a camper van easier to service later?
I’ve used PEX with quick disconnects instead of crimp-only setups. If you ever need to modify something or fix a leak, you can undo connections cleanly instead of cutting everything apart.
7. How big of a water heater do I need in a camper van?
In my experience, people often don’t need as much as they think. I’ve used a 1.5-gallon water heater with a water-efficient shower head and taken 10-minute showers without running out of hot water, but 4- or 6-gallon heaters are more common and might be a safer bet for most.
8. Should I install a propane tankless water heater in a camper van?
I have seen tankless units used as outdoor shower setups mounted at the rear door, but I haven’t installed tankless water heaters inside a van because of exhaust heat and venting concerns.I always felt like they added more complexity than is worthwhile.
9. How do I build a camper van shower that doesn’t feel cramped?
A standard shower pan can feel tight. The roomiest shower I’ve used is a fold-down setup with a curtain, because the curtain gives you space to move and it doesn’t “close you off” the way some doors do. In a 144, I’ve also done a layout where the shower is built into a cabinet and the toilet slides out when needed because space is limited.
