A campervan water system can be as simple as a portable container and hand pump, or as involved as fixed fresh and waste tanks, a pressure pump, hot water and an indoor shower. The useful place to start is not the pump or the tank. It is the complete route the water needs to take.
Plan the system from filling point to tap, then from sink or shower to waste. If every part has a clear job, can be isolated when necessary and can still be reached for maintenance, the plumbing is much easier to live with.
The basic campervan water system
Most systems are built from the same blocks:
- a fresh-water container or fixed tank;
- a way to fill it and, on fixed tanks, normally a way for displaced air to vent;
- a pump or manual/gravity water delivery;
- pipework and fittings;
- one or more taps, shower outlets or appliances;
- a drain from the sink or shower;
- a removable waste container or fixed grey-water tank;
- isolation and drain points where the system needs them.
Hot water adds another branch rather than replacing the cold-water system. The heater takes a cold feed and supplies a hot line back to the tap or shower, so it needs to be chosen before the final plumbing routes disappear behind furniture.
Start with how much plumbing you actually need
A weekend van with a sink may not need a permanently pressurised installation at all. A removable fresh-water container and a small submersible or manual pump can be easy to fill, easy to clean and easy to remove for winter.
A larger touring van with a shower, fixed tank and several outlets is a different job. It normally benefits from a permanent pump, proper isolation, a planned waste system and enough access to service the components without taking the kitchen apart.
The campervan water tank guide compares the practical trade-offs around tank size and position before you commit to the plumbing around it.
Choose the pump to suit the plumbing, not the other way round
There are two common approaches. A submersible pump sits in the water container or tank and pushes water out. An external diaphragm pressure pump sits outside the tank and pressurises the pipework so the tap behaves more like a small household system.
The right choice depends on the number of outlets, the pressure requirements of any heater or tap, the distance from the tank and how permanent you want the installation to be. More pressure is not automatically better. Components downstream have their own limits and the whole system has to be compatible.
Our 12V campervan water pump guide goes into pump types, flow and pressure in more detail.
Does a campervan need an accumulator?
Sometimes. An accumulator stores a small amount of pressurised water and can reduce pulsing, noise and frequent pump cycling in a compatible pressure-switch system. It is useful with some pumps and layouts, but it is not a compulsory part of every pressurised water system.
Some modern by-pass pumps are designed to work without an accumulator. Match one to the pump and layout rather than adding it just because it appears on somebody else’s plumbing diagram.
Keep the pump and strainer easy to reach
A pump hidden in the back of a sealed cabinet will eventually make somebody regret the cabinet. The strainer needs cleaning, pipe connections may need checking and the pump itself may need replacing.
Give an external pressure pump an accessible inlet strainer and pipework that is not needlessly restrictive. Short flexible hose connections at the pump can also help stop normal pump vibration being transmitted into rigid furniture and pipework.
Put the pump somewhere dry and accessible without removing fixed furniture. Leave the same straightforward access to isolation valves and drain points.
Use a pipe system that belongs in the water system
Leisure-vehicle plumbing is available in semi-rigid pipe with matching push-fit connectors, and flexible food-safe hose is also used in appropriate parts of a system. The important point is compatibility.
Use pipe and fittings intended for potable water where they carry drinking water, and make sure their pressure and temperature ratings suit the pump and any hot-water system. Mixing several unrelated fitting families creates more adapters, more joints and more places to chase a leak later.
Where pipe passes through sheet metal, furniture or a floor, protect it from chafing and sharp edges. Keep routes away from exhausts, heater ducts and other heat sources unless the pipe is specifically intended for that environment.
Plan the fresh-water tank as part of the van’s layout
A fixed tank needs more than an outlet at the bottom. Think about how it will be filled, how air will enter and leave as the water level changes, how it will be drained and how you will get to the fittings if one starts leaking.
Choose a tank or removable container intended for fresh drinking water. Before buying it, work out how you will reach inside or otherwise clean, drain and flush it. A useful inspection opening makes a removable container easier to wash out, while a fixed installation needs cleaning and drain access that will not disappear behind furniture.
Keep the filling equipment clean too. Use a fresh-water-compatible hose, funnel or container, keep filler caps and hose ends off the ground, and store the kit clean and dry between uses. Before first use and when returning the van to service after storage, empty stale water, clean the tank or container and filling equipment, then clean and flush the pipework. Any cleaner or sanitiser used must be compatible with the tank, pump and hot-water equipment and flushed through as directed.
Tank position also affects payload and handling. Water weighs roughly one kilogram per litre, so a large tank becomes one of the heavier items in the van when full. That is another reason to decide its position during the layout and weight-planning stage rather than after the cupboards are built.
A fixed tank also needs proper support and secure mounting for its full weight when the vehicle is moving. An underslung tank in particular should not be treated as something that can simply hang from a couple of improvised straps or its pipe fittings. Use a mounting method suited to the tank and vehicle, with the load carried by the supports rather than the plumbing connections.
Grey water needs a proper route too
The water leaving the sink or shower has to go somewhere predictable. A simple van can drain into a removable container carried under the sink or placed outside when parked. A more permanent conversion may use a fixed grey-water tank beneath or inside the vehicle.
Keep the waste route as simple as practical, with enough fall to drain properly and no unnecessary low spots that hold dirty water. A fixed grey-water tank also needs a suitable vent so displaced air can escape as it fills and enter again as it drains. Where smells could travel back through a sink or shower outlet, use a suitable trap or waterless waste valve rather than leaving a direct open route into the tank.
Make sure any fixed tank is securely supported for its full weight, can be emptied without crawling under the van in an unsafe place, and has pipes and valves beneath the vehicle protected from damage.
Hot water changes the plumbing plan
If you want hot water, choose the heating method early enough to design around it. Check its inlet-pressure limit, pipe temperature rating, drain-down method, pressure-relief arrangement and permitted installation position before choosing the pump or fixing the pipe routes.
A typical layout takes a cold branch from the pressurised supply to the heater, then returns a hot line to the mixer tap or shower. Keep the heater, isolation valves and drain points accessible. Hot-water units vary, so follow the heater’s own layout and pressure-relief requirements rather than copying a generic diagram.
Drain-down and frost protection should be designed in
Water trapped in a pump, heater or low section of pipe can freeze in cold weather. Build in accessible drain points and arrange pipe runs so they can empty without leaving hidden low spots full of water.
Make removable connections easy to reach and decide whether vulnerable components will sit inside the heated part of the van or remain exposed beneath the floor. Hot-water equipment may have its own drain-down sequence, so include the access needed to complete it.
Test the system before you hide it
Do not wait until the furniture is finished to find the first leak. Fit the plumbing during the first-fix stage, secure and protect the routes, then test accessible connections before lining or cabinets make them difficult to see.
Once the second-fix components are fitted, fill the system gradually and inspect every joint. Run each outlet, let the pump reach shut-off pressure where applicable and check that it stops rather than cycling for no obvious reason. A pump that repeatedly starts with every tap closed can be an early sign of a leak, trapped air or another system problem that needs investigating.
A simple layout is usually the easiest to own
A well-planned campervan plumbing system supplies the water you actually need, uses compatible parts and remains understandable when something goes wrong. Extra valves, filters and shiny fittings add little if they make the installation harder to trace or service.
Keep the pump and strainer accessible, minimise unnecessary joints, plan the waste side as carefully as the fresh side and make cleaning and draining part of the design. That gives you a system that is easier to build, easier to test and much easier to repair on the road.