Water system basics

Water is heavy

One litre is one kilogram. A 100L fresh tank full is 100kg before the tank itself. Size capacity for how you travel, then place the weight low and between the axles where you can.

Underslung tanks free cabin space and lower the centre of gravity. Internal tanks are easier to insulate and service. Both need secure mounts and protection from road debris.

The simple circuit

Fresh tank to filter to pump to tap, with a sensible pressure switch and a way to drain everything. Grey water needs a tank or a controlled empty, not a hopeful hose under the van in a car park.

Use food-grade hose. Support runs so they cannot chafe. Leave unions you can reach. Label fill and empty points so guests do not invent their own.

Winter and hygiene

Drain down before hard frost. Stagnant water tastes of the tank. Flush and clean on a schedule you will actually keep. If you drink from the system, treat it like drinking water, not like a garden butt.

Leaks

A slow drip behind a cupboard ruins floors and tempers. Hose-test the plumbing before you close the furniture. Keep a small bowl and towel in the kit for the first few trips while joints settle.

Fill less than you think you need until you know your real usage. Empty weight is freedom.

Figures in this guide are planning estimates. Confirm weights and prices against real products, and have gas and electrical habitation work signed off by a qualified person.