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The Ultimate Guide to Campervan Water Systems

Hot water, cold water, showers, campervan taps, pumps, waste water, filtration, piping, and much more. This guide is your complete one-stop-shop for campervan plumbing. Learn everything you could ever want to know about campervan water systems, and more. In this guide I will walk you through several different campervan plumbing diagrams and look at how the campervan water pump system works. I hope this resource helps you build a beautiful campervan that you can be proud of for many years to come!

I'm Shane, I've been teaching people to convert campervans for years; I'm the author of Roaming Home; The Comprehensive Guide for Converting Your Van Into a Campervan, writer of The Van Conversion Newsletter, instructor of The Van Conversion Course over at Udemy. And full-time vanlifer for 4 years!

Now let's jump in and see how to build an awesome campervan water system!

The ultimate guide to campervan water systems

This post contains affiliate links, which means that if you click a product link and buy anything from the merchant (Amazon, eBay, etc.) we will receive a commission fee. The price you pay remains the same, affiliate link or not. By using these links, you are helping me to continue writing free educational content!



Note: Did you know that you can get a free electrical wiring diagram by signing up to The Van Conversion Newsletter

Roaming home

Supplies List 🛒

​Water tanks, piping, and fittings

campervan water inlet

Water inlet

For filling up with water

campervan water tank container

2X ​70L water tank

For holding fresh water & grey water

water tank bulkhead fitting

Selection of bulkhead fittings

Fittings for inlets and outlets on the water tanks. 0.5-1.5 inch required.

Water level sensor

2X Water level sensor

For displaying water levels in the tanks

Water level sensor

​2X water level gauge

For displaying water levels in the tanks

air admittance valve

​Air admittance valve

For allowing water to be drained for the grey water tank without 'glugging'

1/2 inch pex pipe

​1/2" PEX pipe (red and blue)

For piping hot and cold water around your water system

barb to pipe fitting

​Selection of barb-to-pipe fittings

For connecting PEX pipe to bulkhead fittings and appliances

pex fittings

​Selection of PEX fittings

For navigating joints in your campervan water system

Check valve

​Check valve

For preventing the back-flow of hot water

Barbed valve

​A few barbed valves

For inline valves and drains

​Campervan Water Pump Kit

Shurflo silencer

​Shurflo silencers

Mute the noise from the diaphragm water pump

Shurflo strainer

​Shurflo water strainer

For protecting your campervan water pump kit from particulate matter

Shurflo pump

​Shurflo water pump

Diaphragm continuous pressure campervan water pump

Shurflo wingnut fitting

2X shurflo wingnut fitting

For connecting shurflo pump and accumulator

Shurflo accumulator

​Shurflo accumulator

For reducing wear on the water pump and making water flow consistent

Frizzlife inline water filter

Frizzlife inline water filter

Remove water contaminates to 0.5 microns

What is a campervan water system?

Simply put, a campervan water system pipes water from a storage container out to a tap or shower. A simple water system may just have a foot pump and cold water going out to a tap, while a complex system will have a diaphragm pump feeding hot and cold water to a shower and sink. The complexity you wish to add is up to you!

Four campervan water systems

1. The water dispenser

Okay, it’s not really a ‘plumbing system’, but it is as simple as it gets! You can pick up a water dispenser bottle online very cheaply. Put water in the top, get water out the bottom. No more need be said.

Water dispenser bottle

2. The foot pump

The manual foot pump is a nice option that gives you cold water flowing out to a campervan tap. No electricity is required because the pump is operated manually with your foot! We have two large plastic portable containers, one for grey water and the other for fresh water. Whale is a popular manufacturer of foot pumps. The one shown in the diagram is the ‘baby foot pump’, you could also purchase a ‘gusher foot pump’ which delivers more water.

Campervan water system: footpump

3. The 12v submersible water pump

The 12V submersible water pump is a really great option that gives you cold water flowing out to a microswitched faucet. The 12V campervan tap is connected to a submersible pump, when the faucet is turned on, water flows! The submersible pump simply sits in a large plastic portable container full of fresh water. We will look at the wiring of the microswitch faucet later in this guide. Whale also makes the 12v submersible water pump.

12v submersible water pump

4. The heated sink and shower - campervan water system diagram

This is the god-tier campervan water system. This system gives you pressurised hot and cold water running out to a sink and shower. There are mounted fresh and grey water tanks; the fresh water tank is filled from an inlet in the side of the van and has an electrical water level gauge. The grey water from the sink can run either to our grey water tank, or outside the van. The cold water running to the sink tap is filtered, and we can get a mix of hot and cold water (to our liking) to our pressurised sink and shower.

Wow. How good does all that sound!

Though this campervan plumbing diagram can be a little complex to understand at first, it is incredibly fun and rewarding building the system; it feels like plugging Lego blocks together. We are going to go deep on the different components of this system throughout the chapter.

campervan water system diagram

What do I need for a campervan water system?

Now that we have seen the four campervan water systems, let's explore some of the components of each diagram. We will explore the following essential concepts in depth:

  • Fresh water tank

  • Grey water tank

  • Water pump system

  • Sink and faucet

  • Water heater

  • Shower

  • Water piping

  • Pipe fittings

  • Water level gauge

  • Water filtration

  • Pipe insulation / heating

  • Water tank sanitisation and smell management

Let's go! 🍻

Campervan fresh water tank

Surprise, surprise; a fresh water tank holds fresh, potable water… It is the most essential part of a campervan water system

Sizing a fresh water tank

installing a fresh water tank
@dreambigtravelfar installing a fresh water tank

Generally there are three sizes of campervan water tank: small (5L), medium (20L), and large (75L). I personally have four portable 20L fresh water containers in my campervan. If I were to do another conversion, I would install a large 75L fixed fresh water container instead and add a fill point in the side of the van.

Where should I put the fresh water tank in a campervan?

You have two options for where to put your fresh water tank:

  1. Inside the van

  2. Underslung to the bottom of the van

Having a campervan water tank underslung to the bottom of the van is a little more complex to install, but a really nice option that gives you more space inside the van. However, if you are a winter vanlifer (like me) an underslung water tank is probably not the best idea as you are pretty snookered if it drops below freezing outside!

Indeed, Winter vanlifers should keep all parts of the water system inside the van. Installing your fresh water tank inside the van is a safer bet and an easier install.

Note: If you are installing an underslung tank, make sure it is opaque (ie. not clear). Clear tanks in the sun will quickly grow algae which is very harmful for your health if drunk.

In the Roaming Home 2023 study, we found that 62% of people install their campervan water tank inside, 38% install it underslung to the vehicle.

Campervan underslung water tank

Small/medium campervan water tanks can simply be housed directly under the sink. Larger water tanks are normally housed at the back of the van and out of the way.

Let's look at how to mount a large water tank under a van.

Anatomy of a large campervan water tank

A large fixed campervan water tank should have four water outlets:

  1. A Large filling inlet, where we fill the tank with water. This is normally piped to the water filling inlet installed in the side of the van

  2. A smaller outlet running to the appliances (shower/tap)

  3. A vent outlet (the water that runs out of the tank needs to be replaced by air). If you have a filling inlet in your van, it often comes with a vent pre-installed which means you don't have to install a custom vent

  4. And sometimes a drainage outlet which is used when you want to drain the water tank for cleaning

Note: A campervan water tank filling inlet and outlet drain operate by gravity. Ensure your filling inlet is mounted higher than the water tank, and ensure your drain outlet is mounted lower than the tank.

A large water tank may also have metal water level probes pre-installed on the side. These metal bolts (with spade connectors on the end) are in case you want to install a water level sensor in your van. We will look at how to install a water level sensor later in this guide.

how to install inlets on water tank
Pre-installed water tank inlets

How to manually install inlets in a campervan water tank

Sometimes you will end up with a blank water tank that has no outlets pre-installed. In this case, you will need to install them yourself. This can actually be a good thing as it means you get to choose the diameter of the outlets, rather than relying on the supplier.

If your campervan water tank does not have outlets, you can easily install them by first cutting out an appropriate sized hole in the plastic container with a hole saw. The holesaw you use should match the OD (outside diameter) of the outlet fitting you will be using. eg. if the OD of the fitting is 1", use a 1" holesaw!

Hole saw water tank

Next install an appropriate outlet fitting. Here are the typical sizes we use for the inlets and outlets for our fresh water and grey water tanks.

Fresh water tank fittings

Grey water tank fittings

The campervan water tank connector comes with a backing flange that normally goes inside the container and into which we screw. However, if you have no access to the inside of the water container (because there is no access hatch installed), worry not! Without using the backing flange, you can still screw the fitting into the cavity you cut in the container. If you have used the appropriate hole saw size, you should have a perfect seal. Make sure the rubber O-ring is placed between the connector fitting and the water container to get a nice seal.

If the cavity in the water container is a little small, you can heat the plastic a little (using a small blow torch) and then tighten the fitting in place (a pipe wrench is best to tighten fully). If you heat the plastic first, you are actually doing some minor plastic welding which can improve the seal.

After the fitting is in place, I would recommend adding sealant around it to ensure a watertight joint.

Heating the plastic container before screwing the fitting
Heating the plastic container before screwing the fitting

How to install an underslung campervan water tank

Broadly speaking, there are two ways to underslung a campervan water tank to a campervan:

Option 1: Mounting brackets and hook bolts

This is the most sturdy way to install an underslung water tank, however you need to make sure the mounting brackets are perfectly sized for the water tank you have; this can be a challenge if purchased separately.

Water tank mounting brackets
Water tank mounting brackets

To install the mounting brackets, we will need to drill some holes on the underside of the van (be very careful where you drill!). The hook end is placed into the drilled hole and simply hangs there. The water tank is then placed against the underside of the van, and the brackets are secured (thus holding the tank) onto the hook bolts using the nuts provided.

Option 2: Hanger straps

Hangar straps may be a little less sturdy, but are guaranteed to work no matter what size campervan water tank you have.

How to mount a fresh water tank inside your van

Some people choose to keep their fresh water tanks inside the campervan, either for ease of installation, or because of freezing conditions in winter. If you choose to mount your campervan water tank inside, make sure you secure it tightly to the vehicle so it doesn't move when driving. You can use cargo lashing straps to keep it in place (these can also be used to secure your gas bottle).

You could also install wheel arch water tanks - it is a fantastic way to fill an awkward space.