The Complete Guide to Campervan and Motorhome Water Systems — Fresh Water, Hot Water, and Waste Management

How a Campervan Water System Works — The Overview

At its simplest, a campervan water system has three stages: store fresh water, deliver it to a tap, and collect the waste water.

Fresh water is stored in a tank (fixed or portable). A pump pressurises the system and delivers water through pipes to taps, a shower, or other outlets. Used water (grey water) drains from the sink or shower into a separate waste water tank or container.

Hot water is optional but increasingly expected. A water heater — gas, diesel, electric, or engine-powered — heats the cold supply before it reaches the hot tap.

The complexity of the system ranges from a simple jerry can with a hand pump (perfectly functional for weekend adventures) to a fully plumbed, pressurised, hot-and-cold system with fixed tanks, inline filters, and a thermostatically controlled water heater (standard in production motorhomes).

Fresh Water Tanks — Storing Your Supply

Fresh water tanks are the reservoir for all the clean water in your system. They come in two broad categories.

Fixed tanks are permanently mounted inside the vehicle (under a seat, in a locker, or in a purpose-built compartment) or externally underneath the vehicle. They are connected to the plumbing system with permanent fittings and filled via an external inlet. Fixed tanks offer the highest capacity, the most secure mounting, and the most integrated system. They are standard in production motorhomes.

Portable tanks (containers or jerry cans) are removable containers that sit inside the vehicle and connect to the pump system with flexible tubing. They are lighter, simpler, and can be removed for filling and cleaning. They are common in self-build campervans and smaller vehicles where permanent tank installation is impractical.

Tank material. Food-grade polyethylene is the standard material. It is lightweight, durable, and safe for storing drinking water. Ensure any tank you purchase is specifically rated as food-safe and suitable for potable water.

Tank shapes vary widely — rectangular, wedge-shaped, wheel-arch-conforming, underslung — to fit the available space in different vehicles. Measure your available space carefully before purchasing.

Tank Sizing — How Much Water Do You Need?

Water consumption in a campervan varies significantly depending on usage patterns, but general guidelines help with planning.

Basic usage (drinking, cooking, hand washing, washing up) requires approximately 5–10 litres per person per day.

With a shower, add 10–20 litres per shower (depending on duration and flow rate). A daily shower for two people could add 20–40 litres per day.

A practical starting point: For a couple on a weekend trip without a shower, a 20–40 litre tank is adequate. For a couple with a shower for a week off-grid, 80–120 litres provides a reasonable supply. For extended off-grid touring, 100+ litres is common.

Weight matters. Water weighs one kilogram per litre. A full 100-litre tank adds 100 kg to the vehicle. This affects handling, fuel consumption, and payload capacity. Carry only as much water as you need — you can often top up en route.

Tank position affects vehicle balance. Ideally, water tanks should be positioned over or near the axle(s) to maintain balanced weight distribution. A heavy tank mounted at one end can adversely affect handling.

Water Pumps — Getting Water to the Tap

The pump is the component that moves water from the tank to the taps. Without a pump, you have no flow. The pump type determines how water is delivered, how it feels at the tap, and how much noise the system produces.

Submersible Pumps vs Diaphragm Pumps

Submersible pumps sit inside the water tank, submerged in the water. When activated (typically by opening a micro-switch tap), the pump pushes water through the pipe to the tap. When the tap is closed, the pump stops.

Advantages. Simple installation — drop the pump into the tank and connect the pipe. Inexpensive. Quiet when running.

Disadvantages. Flow can pulsate slightly. No residual pressure in the lines — there is a brief delay between opening the tap and water arriving. If the pump fails, it must be retrieved from inside the tank.

Diaphragm (pressure) pumps are mounted outside the tank and draw water through an intake pipe. They pressurise the entire plumbing system, maintaining constant pressure in the pipes. When a tap is opened, water flows immediately because the system is already pressurised. When pressure drops (because water is flowing), the pump activates to maintain pressure.

Advantages. Constant, even flow with no pulsation (especially with an accumulator). Immediate water delivery — no delay. Can supply multiple outlets simultaneously. Feels like a "normal" household tap.

Disadvantages. More expensive. Noisier — the pump activates audibly whenever a tap is opened. Mounted outside the tank, requiring additional plumbing. Can run continuously if there is a leak in the system (draining the tank and flattening the battery).

For most campervan and motorhome installations, a diaphragm pump provides a better user experience. For simpler setups — particularly portable water systems — a submersible pump is perfectly adequate.

Accumulators — Smoothing the Flow

An accumulator is a small pressure vessel installed in the plumbing line after the pump. It stores a small volume of pressurised water, smoothing out the on-off cycling of the pump.

Without an accumulator, the pump kicks on every time the tap is opened and cuts off when the tap closes. This rapid cycling is audible and shortens pump life.

With an accumulator, the stored pressure supplies the first few seconds of water flow before the pump needs to activate. This reduces pump cycling, smooths water delivery, reduces noise, and extends pump life.

An accumulator is a recommended addition for any diaphragm pump system. It is a small, inexpensive component that noticeably improves the system's feel and longevity.

Taps and Faucets

Manual pump taps include a built-in hand pump or are paired with a foot pump. No electricity needed — you pump, water flows.

Micro-switch taps contain a small electrical switch that activates a submersible pump when the tap is turned on. A simple and common setup.

Standard mixer taps (as used in domestic kitchens) work with diaphragm pump systems. They feel and operate exactly like a household tap — turn on for water, adjust for temperature (if hot water is plumbed). This is the most comfortable option.

Choose a tap that matches your pump type. Micro-switch taps pair with submersible pumps. Standard taps pair with diaphragm pumps.

Water Filtration and Purification

Inline water filters are fitted in the plumbing line between the tank and the tap. They remove sediment, chlorine taste, and some contaminants, improving the taste and quality of stored water.

External filling filters are used when filling the tank from a potentially variable water source (such as a campsite tap). They filter the water before it enters the tank, keeping the tank clean.

UV purification systems use ultraviolet light to kill bacteria and viruses in the water supply. They provide a higher level of purification than mechanical filters alone.

For most campervan use, an inline carbon filter provides adequate taste improvement and sediment removal. For extended off-grid touring or filling from uncertain sources, a more comprehensive filtration system is prudent.

Regardless of filtration, always use your fresh water tank for potable water only. Never store non-food liquids in the same tank.

Hot Water Systems

Hot water transforms a campervan from basic to comfortable — hot water for washing up, hand washing, and showering.

Gas instantaneous water heaters heat water on demand as it flows through the unit. No stored hot water — the gas burner ignites when the tap is opened and heats water as it passes through a heat exchanger. Compact and efficient. Requires a gas supply and external flue.

Calorifier (heat exchanger) systems use engine coolant or a dedicated heating loop to heat a stored tank of water. While driving, the engine's waste heat passes through a coil inside the water tank, heating the water. This is common in production motorhomes and provides free hot water while travelling.

Electric immersion heaters heat a stored tank of water using a mains electric element. Only works on hookup. Slow to heat but simple.

Combi heaters (discussed in the heating article) provide both space heating and hot water from a single unit.

Portable instant water heaters are standalone units (often gas-powered) that connect to a cold water supply and provide hot water for an outdoor shower. They are a popular, relatively low-cost option for campervans without built-in hot water.

Showers — Indoor and Outdoor Options

Indoor showers in motorhomes typically use a showerhead connected to the hot and cold water system, draining into a shower tray that feeds the grey water tank. They provide the most comfortable showering experience but require space, waterproofing, and effective drainage.

Outdoor showers are simpler — a portable gas water heater with a showerhead, or a pressurised solar shower bag. Privacy is provided by a pop-up shower tent or the vehicle itself. Popular in campervans where interior space is limited.

Solar showers are the simplest option — a dark-coloured bag filled with water and left in the sun to warm. They provide a few minutes of warm water without any fuel, electricity, or plumbing. Effective in sunny conditions but dependent on weather.

Grey Water Management

Grey water is the used water from your sink and shower. It must be collected and disposed of responsibly.

Fixed grey water tanks are mounted beneath the vehicle and collect waste water by gravity. They are emptied at designated waste water disposal points. Standard in production motorhomes.

Portable grey water containers sit beneath the vehicle's drain outlet and collect waste water in a removable container. When full, the container is carried to a disposal point. Common in caravans and self-build campervans.

Direct drain. In some situations and environments, grey water from a sink (containing only biodegradable soap residues) is drained directly onto the ground. This is acceptable in some camping contexts but prohibited at many campsites and in environmentally sensitive areas. Check local rules.

Never dump grey water containing non-biodegradable cleaning products, food solids, or chemical residues onto the ground. Always dispose of grey water at designated facilities.

Plumbing — Pipes, Fittings, and Connections

Food-grade tubing (typically semi-rigid polyethylene or flexible reinforced hose) is the standard for fresh water plumbing. Ensure all tubing is rated for potable water contact.

PEX tubing (cross-linked polyethylene) is a more robust option used in permanent installations. It is flexible, durable, and resistant to freezing damage.

Push-fit connectors make assembly and disassembly straightforward without specialised tools. They are widely used in campervan plumbing and provide reliable, leak-free connections when fitted correctly.

Hose clamps (jubilee clips) secure flexible tubing onto barbed fittings. Tighten firmly but not excessively — overtightening can cut into tubing.

T-pieces, elbows, and reducers route water around corners, split supply lines to multiple outlets, and adapt between different pipe diameters.

Filling and Managing Fresh Water

External fill points are inlet sockets mounted on the vehicle exterior, allowing you to fill the internal tank with a hose without opening the vehicle. Standard in production motorhomes.

Portable tanks are removed from the vehicle and filled at a tap. This is common in campervans and caravans.

Water sources. Campsite taps, service points, public drinking water taps, and home taps are all suitable. Always use a dedicated drinking-water hose — not a garden hose, which may contain lead or other contaminants.

Tank level indicators show how much water remains. Simple float gauges, electronic sensors, or app-connected monitors provide this information. Knowing your water level prevents the unpleasant surprise of running dry.

Water Hygiene and Tank Maintenance

Stagnant water in a tank can develop bacterial growth, unpleasant tastes, and biofilm on tank walls.

Empty the tank when not in use. Do not leave water sitting in the tank for weeks between trips. Drain completely and leave the drain open to allow the tank interior to dry.

Clean the tank periodically. Purpose-made water tank cleaning solutions (or a dilute solution of food-safe steriliser) kill bacteria and remove biofilm. Rinse thoroughly after cleaning.

Run the taps before drinking. At the start of each trip, run water through the entire system for a few minutes to flush any stagnant water from the pipes.

Replace inline filters according to the manufacturer's schedule. A saturated filter is less effective and can itself become a source of bacterial growth.

Winterising — Protecting the System from Frost

Water expands when it freezes. Ice forming inside pipes, pumps, tanks, and water heaters can crack components and cause leaks — potentially causing significant damage.

If your vehicle will be stored in freezing conditions, the water system must be winterised.

Drain completely. Open all taps and drain valves. Run the pump briefly to clear residual water from the pipes. Disconnect and drain the pump. Drain the water heater. Leave all drain valves open.

Non-toxic antifreeze (propylene glycol, rated as food-safe) can be pumped through the system as additional protection. This displaces any residual water and prevents freezing in areas that cannot be fully drained. Flush the system thoroughly with fresh water before use in spring.

Insulate exposed pipes and tanks if the vehicle is used in cold conditions. Pipe insulation foam and tank wraps reduce freezing risk during use but are not a substitute for draining during extended storage.

Portable and Simple Water Solutions

Not every campervan needs a fully plumbed water system. Simpler solutions are perfectly functional for occasional or minimalist use.

Jerry cans with a tap. A food-grade jerry can with a built-in spigot provides basic water access. No plumbing, no pump, no electricity. Fill, dispense, done.

Collapsible water containers store flat when empty and expand to hold 10–20 litres. Lightweight and practical for weekend trips.

Gravity-fed systems. A container mounted above the tap feeds water by gravity — no pump needed. Simple, silent, and reliable.

Hand pump taps. A manual pump tap draws water from a portable container. No electricity. No complexity.

The Honest Limitations

Water is heavy. Every litre adds a kilogram. A full 100-litre system adds 100 kg to the vehicle — affecting fuel consumption, payload capacity, and handling.

Off-grid water supply is finite. Without access to a tap, your water supply runs down. Conservation becomes a habit — shorter showers, careful washing up, and awareness of consumption.

Hot water requires energy. Gas, diesel, or electricity — hot water is not free. Factor in the fuel consumption and system complexity.

Plumbing can leak. Vibration from driving can loosen fittings over time. Inspect connections regularly, particularly after rough roads.

Frost damages water systems. Any water system that is not properly drained before freezing temperatures is at risk of cracked pipes, burst fittings, and damaged pumps.

Choosing the Right Water System for You

Common Mistakes People Make

Leaving water in the tank between trips. Stagnant water breeds bacteria. Drain the tank after every trip.

Not winterising the system. Frozen pipes crack and leak. Drain before frost arrives.

Installing non-food-grade tubing. Garden hose and industrial tubing can leach chemicals. Use only food-grade, potable-water-rated materials.

Overfilling the tank and exceeding vehicle weight limits. Water is heavy. Know your payload capacity and do not exceed it.

Not fitting an accumulator with a diaphragm pump. The pump cycles more frequently, wears faster, and produces more noise without one.

Running the pump dry. If the tank empties and the pump continues running, it overheats and fails. Fit a pump switch and monitor your water level.

Connecting plastic fittings to metal fittings. Different materials expand at different rates and thread profiles may not match, creating leaks. Match materials — plastic to plastic, metal to metal.

Your Pre-Purchase Checklist

Determine Your Water Needs

Daily consumption multiplied by days off-grid equals minimum tank capacity.

Choose a Pump Type

Submersible for simple systems. Diaphragm for pressurised, multi-outlet systems.

Plan the Hot Water System

Gas instant, calorifier, electric, combi, or no hot water — based on your budget and usage.

Use Food-Grade Materials Throughout

Tanks, pipes, fittings, and filters must all be rated for potable water contact.

Plan Grey Water Collection

Fixed tank, portable container, or direct drain — based on your vehicle and the regulations at your destinations.

Buy a Water Level Indicator

Know how much water remains to avoid running dry.

Plan for Winterisation

If the vehicle will be stored in freezing conditions, drain the system completely and consider food-safe antifreeze.

Why Buying Through Amazon Is a Smart Option

Amazon carries every component of a campervan or motorhome water system — tanks, pumps, accumulators, taps, filters, water heaters, hoses, fittings, and grey water equipment. Customer reviews from self-builders and touring owners provide practical real-world feedback on reliability, flow rates, noise levels, and installation ease — the kind of detail that product specifications alone cannot convey.