Plumbing a Motorhome/Caravan
Whatever you plan to use your motorhome or caravan for, quick weekend trips or months on the road, it makes sense to have a water system installed. Cleaning your teeth in public toilets, washing your dishes in a river and carting around heavy containers of extra water will get old very quickly – it’s much easier to have your own system.
And it’s much easier to install your own. DIY motorhome plumbing is easier than you’d think and can be done on most budgets. Read on for our comprehensive guide on installing a DIY water system for campervan conversions.
Sinks & Taps
Adding a sink and tap to your motorhome is one of the easiest “luxury” things you can do, and will be handy in bad weather when you want to freshen up and do the dishes without having to go outside.
As with other items on the motorhome plumbing list, your sink can be as budget or as fancy as you like, from stainless steel to plastic. It’s the same with taps, pick what you like and what your budget can afford. Remember to buy a sink filter too, to keep solid leftovers and solids out of your drain.
Whatever material you pick for your sink, it’s easiest to opt for a square or rectangular sink bowl rather than a curved or rounded one, as curved sinks are harder to fit. Look for angles that are easy to cut around, so you can install your sink without any hassle.
Fresh Water Tank
This tank will give you all your fresh water for drinking, cooking and washing up. The most important thing here is to buy a tank made out of food-safe material, so that harmful chemicals don’t seep into your clean water.
You will need to calculate how much fresh water you’ll need for at least a couple of days (more if you’re going off the beaten track). This includes drinking water for staying hydrated, water for washing up and water for tea and coffee, as well as water for showers if you have one installed.
A good rule of thumb is to allow for 10 litres of water per day for basic needs, excluding showers. If you’re adding shower water as well, an average shower uses 35 litres of water.
We recommend buying as big a tank as you can fit comfortably under your sink. The following materials work well for a manual pump system:
Refillable plastic water containers
This is the simplest and most budget-friendly way to store fresh water for your campervan. Look for water containers that will fit your locker dimensions.
Refillable plastic water containers are easy to install, just lead the outlet hose from your water pump directly down into the container until it reaches the bottom. Refilling is easy too; take the tank out, fill it up and replace it back inside. (Remember to think about weight if you’re using a tank you’ll have to lift out and carry; each litre of water weighs 1kg.)
If space allows and you’re camping out far from civilisation, you can bring several full water tanks with you. When one runs out, just swap it with the next.
For hygiene and maintenance reasons, empty and wash out your water tank between uses and in winter so the water doesn’t freeze.
Polyethylene water tanks
Coming in a range of styles, shapes and prices, polyethylene water tanks are standard for caravans and motorhomes. You can also get one custom-made for your van’s dimensions and connector locations.
However, polyethylene water tanks are more complicated to install than portable ones. Poly tanks are fixed inside your motorhome, so you’ll have to figure out how to fill it. This will likely be via a remote water inlet and a filler hose.
Grey Water Tank
Next up is the grey water tank, used for waste water. This doesn’t need to be elaborate or expensive as any kind of plastic container will do – just make sure it can fit under your sink.
Grey water tanks work by attaching its opening directly to the drainage hose. Once the tank is full (or once you’re at a campground and want to empty it), disconnect the tank, lift it out and use the park’s grey water disposal station.
As with other items in a DIY plumbing kit, buy a grey water tank according to your budget. An excellent option is a tank with wheels, so you can wheel your tank when it needs to be emptied.
Next up is your water pump. Pumps are needed to compensate for the lack of mains pressure, to ensure that water flows through the pipes and that the correct pressure is maintained.
Manual Water Pumps
These are easiest to use and are cheaper than electric pumps as they don’t use electricity, as well as more efficient in conserving water. There are two options available, hand pumps and foot pumps.
Electric Water Pumps
Electric water pumps start automatically when the pressure inside your motorhome water system drops, meaning you’ll have a constant water flow when needed without having to do anything manually. Their disadvantage is that a constant stream of running water uses more water, which means you’ll need bigger tanks for fresh water and grey water.
Electric pumps can be noisy when running, so should be switched off when you can; this will conserve power too. If the pump has an accumulator, this will hold a little water when the pump is turned off, so you can still fill the kettle or a glass. Accumulators also steady the water stream to avoid oscillating water flow (your pump will sometimes produce this because of its reliance on pressure levels).
As well as the pump, you need filters and strainers for an electric water pump; a strainer at the inlet point to avoid debris getting inside the system and a filter on or in front of the pump to keep the water clean.
Tubes, Hosing & Piping
Piping for a motorhome water system must be non-toxic, non-contaminating, taste-free, and approved for drinking water. If the system is pressurized or will carry hot water, the piping also needs to be suitable for this. The traditional choice for water system plumbing has long been clear PVC reinforced with polyester braid. This same type hose can be used for tank fill and vent connections.
In recent years semi-rigid polyethylene (PE) tubing, has surged in popularity for motorhome plumbing. With quick-connect fittings, a PE tubing water delivery system assembles with relative ease. The opaque or at least semi-translucent nature of the PE tubing discourages algae growth that can be a problem with clear hose. PE tubing also comes in colours to identify you hot and cold piping. Because the tubing is less flexible than PVC hose and it must be cut to the correct lengths, a PE plumbing system will be slightly more demanding to install. However, the primary negative to PE plumbing is the cost of the fittings, which can range in price from $4 to $8 each. On the positive side, the tubing is actually cheaper than reinforced clear PVC hose.
Water Inlet & Filler Hose
If you have a portable water tank, you won’t need a water inlet and filler hose. But if your water tank is fixed, you’ll have to set up tubing to allow you to refill it easily. This means installing a remote water tank filler, mounted to a convenient surface so you can access it easily.
The filler can be attached to the outside of your van or on the side of your counter fixture inside the tank entrance. The latter option is easiest and avoids cutting a hole in the side of your van.
Use a filler hose to connect the water inlet to your freshwater tank, connected by hose clamps on either end. Make sure you place the hose so it slopes towards the tank and avoids air locks when filling.
When looking for a filler hose (or tubing for pipes), ensure that it’s of food grade quality and non-toxic.