Motorhome Water Storage Guide for Australian Trips

A full fresh-water tank feels reassuring when you are leaving the blacktop, but it also adds weight, needs regular care and can become a problem if it is filled from the wrong source. This motorhome water storage guide is designed for Australian travellers who want dependable water for drinking, washing and day-to-day comfort without carrying more than they need.

Start with your tank capacity and payload

Before planning how much water to carry, confirm the usable capacity of your fresh-water tank or tanks. The figure in a brochure is not always the amount you can actually access, and older motorhomes may have been modified over the years. Fill the system at home, noting the water level and how it behaves on the road, before relying on it for a remote stay.

Water weighs one kilogram per litre. A 100-litre tank therefore adds 100 kg before you include hoses, food, recovery gear, passengers and other touring equipment. For some motorhomes, travelling with full tanks is sensible. For others, particularly vehicles close to their gross vehicle mass, it is better to carry enough for the next reliable fill point rather than automatically filling to the brim.

Tank placement matters too. Water carried low and close to the vehicle’s centre is generally kinder to handling than water stored high or well behind the rear axle. If you are unsure how much spare payload you have, check the compliance plate, weigh the motorhome in touring trim and seek advice before adding auxiliary tanks or large portable containers.

Decide how much water your trip really needs

There is no single daily allowance that suits every crew. Two people having quick showers in a motorhome will use far more than two people using campground amenities. Hot weather, children, pets, washing up, toilet type and how often you can top up all change the equation.

As a practical starting point, many couples plan around 15 to 25 litres per person per day when they are careful with showers and dishes. That amount can be reduced for an overnight stop with no showering, or increased substantially when free camping for several days. Keep a separate drinking-water reserve in mind as well. It is useful if a tank develops an odour, a pump fails or a water source is unsuitable.

For longer stays away from services, reducing use is usually easier than hauling another 100 litres. Turn off the tap while brushing teeth, use a washing-up tub rather than letting water run, take navy-style showers, and choose parks with amenities when it makes sense. Good water management is part of comfortable touring, not a hardship exercise.

Fresh water, grey water and drinking water are different jobs

Your fresh-water tank should supply water you are happy to use at the kitchen tap and for personal washing. If your system is intended for drinking water, every component that contacts it needs to be suitable for potable water - including hoses, fittings, filters and storage containers.

Grey water is the used water from sinks and showers. It belongs in the motorhome’s grey-water tank or an approved disposal point, not on the ground beside camp. Rules vary between parks, national parks, rest areas and states, so check local conditions and follow the instructions at the site.

Do not use the same hose for fresh water and sullage. Keeping dedicated, clearly labelled hoses is a simple habit that prevents an unpleasant and avoidable mix-up. Store them separately, with end caps fitted where possible, so dust and insects cannot enter between stops.

Fill from trusted sources and use a clean hose

A tap at a campground is not automatically a drinking-water tap. Look for signage, ask the park manager if needed, and avoid filling from taps marked non-potable, recycled water or wash-down use. When travelling through rural areas, a little planning helps: top up at a known potable source rather than waiting until the tank is nearly empty.

Use a food-grade drinking-water hose, ideally one reserved solely for fresh water. Before connecting, let the tap run briefly to clear any stagnant water from the outlet. Keep the hose end off the ground, avoid dragging it through puddles, and do not allow it to touch the dump-point area. Once finished, drain the hose, cap the ends and stow it away from chemicals and fuel containers.

A pressure regulator can be worthwhile where mains pressure is unknown or unusually high. It helps protect fittings, hoses and plumbing components, especially in older motorhomes. If your vehicle has a tank-fill inlet, never force water in at a rate that causes overflow or back-pressure around the filler.

Maintain the motorhome water storage system

Water tanks are out of sight, which makes it easy to forget them until there is a taste, smell or pump issue. Regular maintenance avoids most surprises. At the start of a touring season, after a long lay-up, or whenever water quality is questionable, inspect the filler cap, breather, hose fittings and drain point for cracks, loose seals or insect entry.

If the tank has been sitting for months, drain it completely and flush it with clean water. A purpose-made drinking-water tank treatment can be used according to its directions to sanitise the system. Run treated water through each tap, including the shower and any external outlet, so the plumbing receives the same attention as the tank. Then flush thoroughly until there is no residual taste or smell.

Filters are helpful, but they are not a substitute for a clean tank or a safe water source. A sediment filter can protect pumps and taps from particles, while a carbon filter may improve taste and odour. Filter cartridges have service intervals for a reason. Leaving an old cartridge in place for years can create the very hygiene issue it was meant to prevent.

RV Options stocks practical water filters and treatments suited to the realities of motorhome touring, alongside the hoses and accessories that help keep a water system orderly at camp.

Watch for signs something is not right

A sudden musty smell, discoloured water, reduced pump flow, pulsing taps or a pump that cycles when no tap is open deserves attention. The cause may be a blocked filter, low tank level, air leak, worn pump valve or a leak in the plumbing. Start with the simple checks: tank level, filter condition, visible fittings and any damp areas around the pump.

Do not assume that clear water is always safe water. If you are concerned about the source or contamination, avoid drinking it until the system has been assessed, flushed and treated appropriately. Carrying bottled water for a short period is a sensible precaution, not an overreaction.

Protect water quality while parked and travelling

Heat is hard on water systems. In much of Australia, a motorhome parked in the sun can have very warm plumbing and tanks for days at a time. Keeping the vehicle cooler where practical, using window insulation while parked, and not storing water unnecessarily between trips all help reduce the conditions that allow unpleasant tastes and microbial growth.

Make a habit of draining the fresh-water tank if the motorhome will be parked up for an extended period, unless the manufacturer advises otherwise. Drain lines and, where relevant, the hot-water system according to its instructions. This also reduces the chance of stale water greeting you on the first trip away.

When travelling on corrugated roads, check tank straps, guards, plumbing clips and hose connections at fuel stops. A small rub point can become a leak surprisingly quickly. Slow down for rough sections and investigate any unexplained loss of water rather than simply refilling and moving on.

Carry a simple water contingency kit

You do not need a cupboard full of spares, but a few items can save a day on the road. A dedicated potable-water hose, hose connectors, a tap adaptor, end caps, a small supply of approved tank treatment, spare filter cartridges and a compact drinking-water container cover most common situations. Add a roll of thread seal tape and a few basic hose clamps if you are comfortable making minor repairs.

The right setup depends on where and how you travel. A couple moving between caravan parks may prioritise a tidy hose and filter arrangement. Travellers heading into the outback may value extra independent drinking-water storage and conservative daily use. Either way, clean water and a well-maintained system give you more freedom to choose where you stop - and more confidence when the next reliable tap is a fair distance down the road.