Need safe, better-tasting water in a campervan, motorhome, caravan or boat? The right filtration system depends on where your water comes from and whether you need to treat drinking water only or every outlet in the vehicle.

This guide explains the main options for mains-treated water, uncertain supplies and off-grid water sources.

Choosing a Water Filter for Your Campervan, Caravan or Boat

When travelling in the UK, Europe or farther afield, you may usually be able to fill your onboard tank with potable, mains-treated water. However, water quality, taste and storage conditions can vary.

Even when using a campsite hook-up, it is worth considering the condition of the supply tap, connecting hose and onboard tank. Hoses and fittings exposed to heat can encourage bacterial growth, particularly when water has been standing for some time.

Option 1: Better-Tasting Drinking Water from a Trusted Supply

If you fill your tank from a reliable mains-treated supply, a simple carbon drinking-water filter may be all you need.

A taste-and-odour filter can:

• Improve unpleasant tastes and smells
• Reduce reliance on bottled drinking water
• Provide a compact and relatively simple installation
• Supply filtered water through a dedicated drinking-water tap

Please note: a standard taste-and-odour filter is not intended to disinfect untreated water and should not be relied upon to protect against bacteria, viruses or other microorganisms.

View our taste-and-odour filter kit for campervans, caravans and boats .

Option 2: Drinking-Water Treatment for a More Uncertain Supply

Where the supply is less certain, additional protection may be appropriate. Depending on the source, this may include ultraviolet treatment, sediment pre-filtration and a point-of-use drinking-water system.

Ultraviolet Treatment

A correctly sized UV system is designed to inactivate microorganisms as water passes through the unit. UV performance depends on the water being sufficiently clear, the correct flow rate being maintained and the equipment being properly serviced.

UV treatment does not remove sediment, dissolved chemicals, salts, metals, unpleasant tastes or odours. For that reason, it is normally used as one part of a treatment system rather than as a solution to every possible water-quality problem.

View our 12V off-grid UV system with pre-filter .

Reverse Osmosis for Drinking and Cooking Water

A point-of-use reverse osmosis system can provide highly filtered water at a dedicated drinking-water tap. It may be useful where you want additional reduction of many dissolved contaminants, but suitability depends on the water source and system specification.

Before fitting reverse osmosis in a campervan, motorhome or boat, consider:

• Water pressure: the system requires adequate pressure, usually provided by the onboard pump or hook-up supply.
• Available space: most systems include filters and a small storage vessel.
• Water consumption: reverse osmosis produces a reject-water stream as part of normal operation.
• Connections: your existing pipe size and tap arrangement may require suitable adapters.

The reject water may be collected separately for an appropriate non-drinking use, subject to the original water quality and your installation.

View our reverse osmosis drinking-water system .

Option 3: Treating Water for Every Outlet, Including the Shower

If uncertain water will be used for showering, brushing teeth, washing food or filling every tap, treating only the kitchen drinking-water outlet may not provide sufficient protection.

Small amounts of water can be swallowed while showering or brushing your teeth. A whole-vehicle UV system may therefore be appropriate where microbiological contamination is the main concern.

Where Should the UV Unit Be Installed?

The UV unit should normally be installed after the onboard storage tank and before the water is distributed to the outlets.

Avoid disinfecting water and then leaving it in an unprotected storage tank for an extended period. Water should be treated as close as reasonably practical to the point at which it will be used.

12V or Mains-Powered UV?

A 12V UV unit is usually the most practical choice for an off-grid vehicle. A standard mains-powered UV may be operated through an appropriate electrical supply or inverter, but inverter use can place an additional demand on the battery system.

Choosing the Correct Flow Rate

UV systems are sized according to the maximum rate at which water passes through them. If the flow is too high for the unit, the water may not receive the required UV exposure.

You can estimate your flow rate using a bucket and stopwatch:

1. Run the outlet at its normal maximum flow.
2. Collect the water for a measured period.
3. Convert the volume collected into litres per minute.

See our guide to measuring water flow rate, or contact us with your litres-per-minute figure for help choosing a suitable unit.

Can I Take Water from a River, Stream or Lake?

Water from a natural source should be treated as potentially contaminated. A simple carbon filter or UV unit alone may not be sufficient.

Depending on the source, untreated water can contain:

• Sediment and suspended material
• Bacteria, viruses and protozoa
• Agricultural run-off
• Fuel, pesticides or industrial chemicals
• Dissolved metals or minerals

A suitable setup may require staged sediment filtration, specialist contaminant reduction and disinfection. The correct system should be chosen after considering the source and, where appropriate, obtaining a water test.

Terminology note: untreated water taken from a natural source is commonly called raw or source water. In campervan and boating use, “black water” normally refers to sewage or toilet waste and must never enter a drinking-water system.

Do I Need Both UV and Reverse Osmosis?

Not necessarily. The two technologies perform different jobs:

• UV is used for microbiological disinfection.
• Reverse osmosis reduces many dissolved substances in drinking and cooking water.
• Carbon filtration is commonly used to improve taste and odour and reduce certain chemicals.
• Sediment filtration protects downstream equipment and removes suspended particles.

Your ideal combination depends on the water source and what you need to remove. Even when a whole-vehicle UV system is fitted, you may still choose a carbon filter beneath the kitchen sink to improve the taste of drinking water.

Maintenance

All filters require routine servicing. Exact replacement intervals depend on the product, water quality and manufacturer’s instructions.

Carbon Taste-and-Odour Filters

Replace the cartridge at the recommended interval, including after long periods of storage where required. Once a cartridge has been wetted, leaving it unused for extended periods may allow bacterial growth.

Reverse Osmosis Systems

Pre-filters and post-filters need periodic replacement, while the membrane normally lasts longer. Replacement frequency will depend on feed-water quality, use and the particular system.

UV Systems

UV lamps must normally be replaced at the specified interval even if they continue to illuminate, because their effective UV output reduces with age. Pre-filters should also be checked and replaced when required. A noticeable reduction in flow may indicate that a sediment cartridge is becoming blocked.

Choose Widely Available Cartridge Sizes

Standard or universal cartridge sizes are particularly useful when travelling. They are generally easier to replace than a proprietary cartridge that may only be available from one supplier.

Connections and Installation

Drinking-water and reverse osmosis kits commonly use compact tubing and may include a separate filtered-water tap. Depending on your existing installation, adapters may be available so that you can retain your current tap or connect to a different pipe size.

UV systems and their pre-filter housings may use larger threaded or push-fit connections. Please check your pipe diameter, pump pressure, maximum flow rate, available space and power supply before ordering.

What About Grey Water?

Grey water is water that has already been used for showering, handwashing or washing dishes. It can contain detergents, grease, food residue, microorganisms and a wide range of dissolved chemicals.

Recycling grey water into potable water inside a compact campervan is complex, energy intensive and difficult to monitor safely. A basic sediment filter, carbon cartridge or UV unit should not be assumed to make used grey water safe to drink.

Need Help Choosing?

Campervan and boat installations vary considerably. To help us recommend a suitable setup, please provide:

• Your expected water source
• Whether the water is for drinking only or the whole vehicle
• Your maximum flow rate in litres per minute
• Your pump pressure, if known
• Your pipe or tubing size
• Whether you have 12V, mains power or an inverter
• The space available for the equipment

Contact our team to discuss your campervan, motorhome, caravan or boat water-filtration requirements.