Campervan Water Systems: Complete Guide
A reliable water system is one of the most significant upgrades you can make to a campervan build. Fresh water on demand — for cooking, washing up, and showering — transforms off-grid living from a camping trip into something genuinely comfortable. This guide covers everything from tank sizing and pump selection to water heating, filtration, and winterising your system for cold-weather travel across the UK, Germany, and the Netherlands.
Planning Your Water System: Key Questions First
Before buying components, answer three questions: How many people will use the van? How many days between refills can you realistically expect? Do you want a shower?
A single person living full-time in a van typically uses 5–10 litres per day for drinking and cooking, and 8–15 litres for a brief shower. A couple might use 25–40 litres per day with a shower. If you plan two to three days between fill-ups and want the option to shower, a 60–80 litre tank is a sensible starting point. Larger tanks (100–120 litres) give greater autonomy but add considerable weight — water weighs 1 kg per litre, and a full 100-litre tank is 100 kg.
Fresh Water Tanks
Purpose-made plastic fresh water tanks are available in a wide range of shapes and sizes, and can be fitted under the van, in a side locker, or beneath a bed frame. They are typically made from food-grade polyethylene (PE) and are safe for drinking water storage.
Tank Placement
Under-floor tanks offer the best use of interior space but require cutting a hole in the floor for filling and drainage, and may be vulnerable to damage on rough roads or during ferry crossings. Underseat and underbed tanks are easier to access and inspect. Whatever the location, ensure the tank is securely strapped or bolted — a loose 80-litre tank during an emergency stop is genuinely dangerous.
Inlets and Gauge Senders
Fit a standard caravan-style bayonet fill point on the exterior of the van so you can use campsite water points without needing a hose adaptor. A float sender connected to a dashboard or panel gauge lets you monitor water level at a glance, avoiding the unpleasant surprise of an empty tank mid-shower.
12V Water Pumps: Pressure vs Switch-Driven
The 12V water pump draws water from your tank and delivers it to taps and shower heads. Two main types are used in campervans.
Pressure-Controlled (Self-Priming Diaphragm Pumps)
This is the standard choice for campervan builds. A pressure switch inside the pump detects when you open a tap and starts automatically. When you close the tap, pressure builds, and the pump switches off. Brands like Shurflo, Fiamma, and Whale dominate this market.
Look for a pump delivering 8–11 litres per minute at 2–3 bar pressure. The 12V current draw is modest — typically 5–8A — so these pumps have a negligible impact on your battery budget. Self-priming capability (the pump can draw water even when not flooded) is standard on quality units and is important when the pump is mounted above the tank.
Switch-Driven (Manual Pump) Systems
Some builders prefer a simple 12V pump wired to a rocker switch — you press the switch to run water and release it to stop. This gives very precise control over water usage and eliminates the noise of a pressure switch cycling on and off. It is slightly less convenient but saves water, particularly for rinsing tasks.
Accumulator Tanks
An accumulator tank (a small pressurised vessel, typically 0.5–1 litre) connected between the pump and the taps reduces pump cycling, smooths pressure fluctuations, and prolongs pump life. They are inexpensive and worth fitting in any permanently plumbed system.
Taps, Sinks and Connections
Caravan-style mixer taps use push-fit connectors on 10mm or 12mm John Guest push-fit fittings — the same system used throughout the caravan and motorhome industry. These are quick to install, completely reliable, and easy to modify or repair. Avoid solvent-welded rigid pipework inside a van: vibration causes fatigue cracking over time.
For the sink itself, a stainless steel caravan sink with a drainer is the most durable choice. Composite sinks look attractive but can crack under the stresses of van life. Keep the sink shallow (100–120mm) to fit within a standard worktop thickness while leaving adequate storage below.
Taps with integrated aerators reduce water consumption noticeably — a worthwhile feature when operating from a finite tank. Some builders fit foot-operated tap valves, borrowed from marine and hospital practice, to give hands-free control when cooking.
Grey Water Tanks
Grey water is everything that drains from your sink and shower — washing-up water, shower runoff, and any food residue. In most European countries, including Germany and the Netherlands, you are required to collect grey water rather than dumping it on the ground. In the UK the rules are less codified but responsible disposal is increasingly expected on wild camping spots.
A grey water tank of 30–50% the capacity of your fresh tank is a reasonable proportion — if you carry 60 litres fresh, a 30-litre grey tank will usually keep pace. Under-van tanks are common, or a portable "jerrycan" style container can be used and emptied at campsites or motorhome service points.
Fit a coarse strainer in the drain plug of your sink to prevent food scraps entering the grey tank, which would otherwise cause odour problems. A small amount of enzyme-based grey water treatment will control smells in warmer weather.
Water Heaters: Gas, Diesel and Electric
Hot water makes washing up and showering significantly more comfortable, and there are three main approaches for campervans.
Gas Water Heaters (Truma, Whale)
Truma's AquaGo is a popular instantaneous gas water heater, delivering 10–12 litres of hot water per minute without the need for a storage tank. It requires LPG (propane or butane) supply and adequate ventilation, but produces hot water on demand with no warm-up time. The compact Whale Expanse heaters are a more affordable alternative for smaller vans.
Diesel-Fired Water Heaters
Some diesel heating systems — notably the Webasto Thermo Top — integrate water heating with cab heating, using the van's diesel tank. This removes the need for a gas supply entirely and suits builders who prefer an all-electric and diesel van with no LPG. Dedicated diesel water heaters are less common than diesel space heaters but are available from Webasto.
Electric Water Heaters (12V and 230V)
Electric immersion-style calorifiers (typically 5–10 litres) run on 230V from a hook-up or inverter, and can also integrate with a diesel heating system via a heat exchanger. The Surecal and Whale ranges are well-regarded. A 5-litre 230V calorifier takes 30–45 minutes to heat from cold but, once hot, provides comfortable shower temperatures for a brief 5–7 litre navy shower.
On-demand 12V inline heaters exist but typically require 180W or more — workable from a lithium bank but a significant continuous draw. They suit supplemental heating of already-warm water rather than heating from cold.
Campervan Showers
A shower in a campervan is a genuine luxury and very achievable even in modest-sized vans. The two main configurations are a wet-room (full shower tray and waterproof walls) and a compact shower tray with a retractable curtain that doubles as a changing area.
A "navy shower" — wet, soap, rinse — uses as little as 5–8 litres of water. A flow-restricting shower head (rated 6–8 litres per minute rather than a domestic 12–15) makes a meaningful difference. Dometic and Whale both make compact caravan shower heads designed for low-pressure 12V systems.
Ensure the shower drain connects to your grey water tank and not directly to the road surface. Fit a trap in the drain line to prevent smells from the tank entering the living space.
Water Filtration
When touring across Europe, water quality varies considerably between countries, regions, and campsite water points. A simple inline pre-filter (20-micron sediment cartridge) upstream of the pump protects pump diaphragms from grit and particulates. If you are drinking directly from the tank, add an activated carbon filter downstream of the pump to remove chlorine and improve taste.
Ceramic filters or UV sterilisers are worthwhile for travellers filling from rural sources of unknown quality. However, for the vast majority of UK, German, and Dutch campsite water points, a basic sediment filter is entirely adequate.
Winterising Your Water System
Water left in pipes, pumps, and tanks during freezing temperatures expands and can split plastic pipes, crack pump diaphragms, and damage fittings. If you plan to leave the van unused over winter, or to travel in temperatures below 0°C, winterising is essential.
- Drain the fresh water tank completely via the drain plug or tap.
- Run the pump until it purges all water from the lines — leave taps open while doing this.
- Blow compressed air through the system if available, to clear water from pump diaphragms.
- Add non-toxic, food-safe antifreeze (propylene glycol based) into the pump and pipe runs if the system cannot be fully drained.
- Drain the grey water tank and leave the drain cap open so any residual water can escape.
- Remove the filter cartridge, rinse it, and store it dry to prevent mould growth.
For year-round vanlifers in the UK and northern Europe, pipe insulation (closed-cell foam lagging) on all exposed pipe runs significantly reduces the risk of freezing during cold nights. Parking in a location sheltered from wind also makes a notable difference.
Plumbing Layout and Diagrams
A clear, logical plumbing layout makes maintenance and fault-finding straightforward. The recommended sequence is:
- Fresh water tank with fill point and drain plug
- Pre-filter (sediment, 20 micron)
- 12V water pump
- Accumulator tank
- Cold water line splits: one to tap(s)/shower cold, one to water heater inlet
- Water heater — hot outlet runs to tap(s) and shower hot
- Sink and shower drain to grey water tank
Use push-fit John Guest fittings throughout for flexibility and ease of modification. Label all pipes where they run behind walls, and leave an accessible service point (typically at the pump) where you can disconnect the system quickly if needed.
Frequently Asked Questions
How big a water tank do I need for a campervan?
For two people with a shower, a 60–80 litre tank provides 2–3 days' autonomy with careful use. If you fill up at campsites or petrol stations every day or two, 40–60 litres is sufficient. Wild camping for a week at a time without resupply points requires 100 litres or more, plus careful water conservation habits.
What is the best 12V water pump for a campervan?
Shurflo's 2088 series and the Whale Gulper range are both well-regarded for reliability and ease of maintenance. Look for 8–11 litres per minute at 2–3 bar, with self-priming capability. Pair any pump with a small accumulator tank to reduce cycling and extend pump life.
Can I drink water from my campervan tank?
Yes, provided the tank is food-grade polyethylene, you use food-safe fittings, and you regularly clean the tank with a Milton or similar sterilising solution. An inline activated carbon filter downstream of the pump will improve taste and remove residual chlorine from campsite water supplies.
How do I stop my campervan water pipes freezing?
Insulate all pipe runs with closed-cell foam lagging. If temperatures will drop below −5°C and the van is unoccupied, drain the system completely and introduce non-toxic propylene glycol antifreeze. A diesel heating system running on a low overnight setting will also keep the interior warm enough to prevent freezing.
Where can I empty my grey water tank in the UK and Europe?
Motorhome service points (EHU/waste points) at campsites and aires are the standard option. In the UK, many motorway service stations and Caravan and Motorhome Club sites have dedicated waste points. In Germany, Reisemobilstellplätze (motorhome stopovers) almost always include a grey water drain. The park4night and Campercontact apps list grey water disposal facilities across Europe.
