If the plumbing aisle at Home Depot gives you nightmares, this guide’s for you. Building a campervan water system can be of the most confusing tasks in a van conversion but it doesn’t have to be, let’s get into it.
- Our Plumbing Diagram
- Campervan Water Tanks
- Water Pumps
- Sinks, Faucets & Drains
- Plumbing Components
- Hot Water
- My Two Cents
Our Campervan Water System Diagram
Above is how the plumbing in our van is laid out. It’s not the most complicated but it’s not the simplest either. Let’s go though each element together.
Campervan Water Tank
Fresh Water Tanks
Fresh water tanks will store your clean drinking water and are sold by gallon capacity and dimensions. A 20 gallon tank, for example, can come in many different shapes so to find the right tank for you, you need to know (1) where it will be located and (2) how many gallons you want. How many gallons will you need? We have a 20 gallon tank in our van and it will last a week if we’re very careful. Two people can easily use a few gallons a day especially if you’re in the desert, do a lot of cooking or have a dog. Finding water can be a struggle sometimes so having a larger tank just means having to fill up less often.
A fresh water tank will usually have three or four openings. Two openings will be on the top, the fill and the vent and the other openings will be on the bottom and used as the main outlet and potentially a second outlet. Make sure to include a shut off valve at the outlet(s) of your tank (see our diagram above). If you have two outlets at the bottom, you can use one as a drain that empties your tank outside, or you can plug it.
Material and Sourcing
Campervan water tanks are typically made from rotomolded polyethylene which is food grade and FDA approved for potable water. Plastic-Mart.com has a great selection of tanks of any size and will also custom fabricate a tank for you if you need. They will also install an inspection port in any of their prefabricated tanks. You can also find tanks on Amazon with mixed reviews. Because it’s such an important element of your build, we opted to go with a reputable manufacturer.
Your campervan water tanks can either be mounted under your vehicle or inside your vehicle, depending on your needs. If you plan to spend a lot of time in freezing temperatures, perhaps mounting your water tanks outside isn’t a good idea. You can get silicone heating mats to keep your tanks from freezing if mounting inside wont work for you. Usually the grey water drain pipe is the first thing to freeze.
Because water is so heavy (8.33 Lbs per gallon) its important to consider weight distribution as well when deciding on where to mount your tank. Over the rear axle is a good place. If you place you tank to one side of your van, lets say passenger side, then try to equalize the weight on the driver side with batteries or other heavy stuff like tool storage. Wherever you do decide to put it, securing it properly is important. I recommend using metal brackets and/or nylon straps that are bolted to the metal of your van to secure your water tank. If your tank moves at all while driving, it could wear a hole over time so padding the tank near the mounting brackets is a good idea.
You will need to have a water fill port somewhere on your vehicle. This can be located on the outside or inside, but wherever it is, it must be easy to access. We opted to mount ours inside, right behind the side door because (1) its less holes to drill in the van (2) its stealthier and (3) it prevents anyone from messing with our water supply. You can find ones with locking caps for better piece of mind if you plan to mount yours on the outside.
You should clean your campervan water tank before installing it in your van and I highly recommend installing an inspection port so that you can clean it again later. The tank will have plastic debris and dust inside from manufacturing and transport. If you didn’t get an inspection port installed from the manufacturer, you can do it yourself really easily. Just cut a hole with a jig saw and use a food grade adhesive sealant around the flange and hardware. I recommend the Silco brand found below. You can use a mild vinegar solution to wipe out the inside of your tanks or a stronger bleach solution if needed.
In between physically cleaning your tank, you can use bleach water to disinfect it and your water lines. The EPAs recommended guidelines for disinfecting water are below.
Only use regular, unscented chlorine bleach products that are suitable for disinfection and sanitization as indicated on the label. The label may say that the active ingredient contains 6 or 8.25% of sodium hypochlorite. Do not use scented, color safe, or bleaches with added cleaners.
Just fill your tank with the correct ratio of bleach : water using the chart above. Run some water though the faucet to ensure the bleach water mixture is going though the system and let it set for a few hours or overnight. Empty the tank and flush the entire system with clean water. Note that chlorine has been shown to damage PEX tubing, do your own research.
Holding tanks will either be used for grey water (the stuff from your sink), black water (the stuff from your toilet) or both. Most DIY van builds don’t have flushing toilets so most of the time we’ll be dealing with gray water only. Holding tanks are often made from a different material then fresh water tanks because they don’t need to meet certain FDA guidelines. Just like freshwater tanks, grey tanks are susceptible to freezing so consider your needs before deciding where to put it. We opted to use a very small 3 gallon tank which we keep inside under our sink for our grey water. Although it’s small and we have to empty it often, we can carry it into pit toilets, porta-potties, or public restrooms very easily and discreetly. Because we have more options on where to dump it over a traditional RV that has to use a dump station, its pretty convenient and we don’t plan on changing.
Dumping your gray water on the ground is controversial in the vanlife community. Whenever possible, dispose of your gray water properly.
Campervan Water System Pumps
Water pumps will transfer the water from your fresh tank to your faucet or other outlets. They keep the system pressurized at all times so your faucet will work just like the one in a house. When the pressure in the system reaches a certain PSI, they turn off automatically, and when you open the tap, they sense the pressure drop and kick on. They operate on 12V but draw significant current so design the correct gauge wire and fuses into your wiring diagram to accommodate. It’s important to wire your water pump to an easily accessible switch so you can cut power to your pump when you leave your van unattended for a while. This will prevent your pump from emptying the entire contents of your tank into your van in the event of a water leak. You should install a strainer between your tank and pump to catch any large debris before it reaches your pump.
You can alternatively opt for a manually operated water pump. These will help save power, be easier to install because there are no wires or switches, and save water. There are foot and hand operated water pumps to choose from.
Accumulators will smooth out the flow of water coming from an electric pump in your campervan water system. If you opt for a manual pump, an accumulator will not be necessary. If you don’t have an accumulator, the water flowing from your faucet will pulsate because of the pump and its pretty annoying. They also extend the life of your pump, because it cycles on/off less often, and makes it quieter. Installing an accumulator isn’t hard or expensive so it’s definitely a must for us. The accumulator will need to be filled with air to a certain PSI, you can do this with a bike pump or any air compressor. The specific PSI will depend on your pumps cut off pressure, but it’s usually something around 40 PSI.
Campervan Water System Filtration
The quality of water you’ll find on the road will vary greatly so you’ll want to take some extra steps to make sure what you’re drinking wont ruin your weekend. We’ve found that most water on the road is hard and will start to buildup and leave limescale residue, all the more reason to add good filtration. We recommend a three stage filtration system, sounds complicated but it’s not. First stage should be a pre-tank filter that you connect to the hose you use to fill up your water tank. Stage 2 is a particulate strainer between your tank and pump; this will catch anything the pre-tank filter missed or that builds up inside your tank such as lime scale. Stage 3 is a simple under sink carbon filter; this will make the water taste better and filter any remaining impurities so they don’t build up in your faucet.
Sinks, Faucets & Drains
There’s nothing special about campervan sinks except they are probably smaller then the one found in a house. We used this 15″x14″x8″ stainless sink in our campervan water system and are pretty happy with it. We’ve seen people make their own sinks out of salad bowls or galvanized tubs, the sky is the limit. Searching for ‘bar sink’ will return some small sinks in odd shapes.
If you plan to use a traditional faucet found in a house with a mixing tap it’ll have two supply lines, one for hot and one for cold (most likely 3/8″ FCM). If you don’t plan to have hot water on tap (who does) then you’ll need to combine both supply lines into one so cold water comes out regardless of where the faucet handle is. A 3/8″ Add-A-Tee compression fitting like the one below (left) or a dual outlet stop valve (right) should do the trick for you.
If your sink didn’t come with the strainer (sometimes called the basket) installed or you made your own sink and need to install the strainer, you’ll need to get some plumbers putty. Check out this quick video that shows step by step how to install the strainer.
Don’t forget to include a P-trap in your sink drain, this will prevent any smells coming up through your drain from the grey tank. Most van builds don’t have enough space under the sink for traditional PVC P-traps but you have a couple options that are made for RVs. We have the black one below on the right. It screws directly onto the sink strainer and has worked well for us. It comes completely apart if (when) you need to clean it. Alternatively you could try the low profile waterless trap on the right. I don’t have any experience with it, but amazon seems to like it.
If you’re really tight on space under your sink, this swivel drain connector might make your life a little easier.
Campervan Water System Plumbing Components
Hoses / Pipes / Tubing
PEX is a flexible plastic pipe that comes in blue and red to distinguish hot and cold water and is becoming the standard in new home construction, replacing copper pipe. Its a good choice for a van build however there are a few downsides. It’s not flexible enough to bend the tight corners in a van so you’ll have to use a lot of 90 degree elbows which increase the cost. You’ll also have to purchase a tool if you’re going to use crimp or clamping connectors, more on that in the fittings section below.
Braided Supply Line
Braided supply line can be used to connect elements of your plumbing system together and it’s what we used in our van exclusively. It comes in many different lengths and fitting sizes, is really flexible and it’s easy to install without any special tools. Knock on wood, we haven’t had any leaks so far.
Braided Vinyl Tubing
Vinyl tubing can be a good option if you need a very long run of tubing that snakes around corners where PEX would require too many connectors to navigate. Just make sure what you’re purchasing is rated for drinking water use.
Fittings is where plumbing can get confusing. Always make sure your fittings are lead free and rated for potable water.
Threaded Fittings (MIP, FIP, NPT, MGH, FGH, FCM)
Threaded plumbing components will likely have NPT threads which stands for National Pipe Thread and is a US standard. NPT is a tapered thread style that uses friction to seal water and gas lines. MIP and FIP are the male and female versions of NPT. They stand for Male Iron Pipe and Female Iron Pipe respectively. Sometimes FIP can be referred to as FPT and MIP as MPT. FIP fittings will have threads on the inside and MIP fittings will have them on the outside. You will want to use a thread sealant on all threaded fittings. If it is metal to metal a Teflon tape is ideal but if the fitting is plastic, it’s best to use a liquid sealant such as this to not promote over tightening, which could crack the plastic fitting.
MGH and FGH stand for Male and Female Garden Hose. Sometimes you will need to adapt a NPT threaded component to a garden hose fitting depending on your setup.
CM stands for Compression so FCM refers to a female compression fitting, but they are usually just called compression fittings. They have three parts and work by compressing a ferrule (the copper ring) onto the pipe with a nut. They can be used to join pipes of different material together. You can also discard the ferrule and nut and screw directly onto the fitting with a braided hose for example (make sure to use thread tape).
Push-to-connect style fittings don’t require any tools to install, you simply push the end of the pipe into the fitting. The most popular brand is SharkBite. They will work with PEX tubing and they have adapters to connect threaded components to PEX. They are the most expensive option but also the easiest to install. I’ve heard that they are more prone to leaks then crimping or threaded fittings.
Crimp on fittings for PEX require a crimp tool that only works with one size of PEX. Although crimping is a good method, for the average person, clamping (below) is a better solution.
Similar to crimping, clamping will also require a special tool, however this tool can be used on any size fitting, where as the crimp tool is specific to a certain size. Clamps are also easier to remove then crimp rings and clamping tool will ‘release’ when an acceptable clamp is applied vs. having to check a crimp with a gauge tool. For these reasons, I think clamping is a superior method then crimping for the DIY van builder.
Hose barb fittings will allow you to adapt a threaded component, such as your water pump, to vinyl tubing for example. They are prone to leaks but using a quality hose clamp will help. I don’t recommend using barbs if possible.
Hose clamps will be used with barb fittings. I recommend using two clamps whenever possible because they have a tendency to loosen over time. Only use two if there is enough barb under the hose otherwise the second clamp could help pull the hose off the barb. Fuel hose clamps are much better then the worm gear type if your want some extra piece of mind. Fuel hose clamps can also be called high pressure hose clamps.
Winterization is the process of preparing your campervan water system for hibernation. There are a couple tricks to make sure you don’t come back to cracked water lines or a jungle growing inside your tank. First, you’ll want to invest in a blow out valve. This will allow you to use compressed air to blow all the water out of your lines so they don’t freeze (just make your water fill port has threads on the inside). Another good idea is to pour some bleach into the tank just before you blow it out. Because you’ll never get 100% of the water out, this will ensure the water left in the tank and lines wont get funky. Click here to go back up to the bleach water ratio recommendations.
Alternatively you can use an antifreeze solution.
On Demand Heaters
On demand propane water heaters are a pretty popular way to get hot showers on the road. They are cheap and and supply unlimited* hot water. I’ve heard they can leak propane so it’s best to keep them outside or disconnect the propane when not in use.
*limited to your water tank capacity
Heaters with Tank
Built in heaters are non common in DIY builds mainly because of their power consumption, but they do exist and come in gas and electric varieties. This is the only way to get hot water from your faucet that I’m aware of.
Solar showers are an easy and inexpensive way to get hot showers on the road. They wont get as hot or last as long as an on demand propane heater, but they don’t require any plumbing and are small and lightweight to store. You just have to plan ahead a little bit and wait for the sun to heat up the water.
When we want to take a hot shower, we boil some water in the electric kettle and mix it with cold water in a garden sprayer. Its pressurized unlike a solar shower and we can control the temperature more too. We decided to swap the spray nozzle to a kitchen faucet sprayer and it works great.
There are a few accessories you’ll need to round out your campervan water system.
My Two Cents
If plumbing intimidates you, or even if it doesn’t, just keep your plumbing simple. There will be less to go wrong, less expense and less headache. Plus plumbing is pretty easy to modify if you ever want to add features later so don’t feel like you need to get it 100% right the first time, especially if this is your first van build. I highly recommend braided supply line for those who don’t want to invest in the tools necessary to work with PEX, it’s what we used in our van, it works great and is easy to install. If you want to use PEX go with the clamp rings, not the crimp rings and don’t waste your money on Shark Bite fittings. Take the time to use thread tape on metal fittings or thread sealant on plastic fittings. Don’t forget to include a shut-off valve at your tank and a drain trap under your sink.
Hope this helps you build the van of your dreams. Check our our van build shop for all the things we used in our van build.