Winterising a motorhome or caravan: water, waste, warmth and the battery

People use the word for two different things. One is getting a van ready to tour in the cold: keeping water, waste, heat and power working when the nights fall below zero. The other is laying a van up for the winter so the frost can't damage it while it sits on the drive or in storage. This guide covers both, starting with touring, because a van that is ready to tour in January is most of the way to being safe in storage too.

External water tanks are at risk of freezing in winter even when well insulated, unless you give them a heat source, the Camping and Caravanning Club says. An insulated jacket that also covers the inlet pipe to the van is the basic requirement for an Aquaroll or similar in the depths of winter. Once a container has frozen, ordinary winter daytime temperatures can take a very long time to thaw it.

Two simple habits help. Keep a small container of water inside overnight, for the first cup of tea, the Caravan and Motorhome Club suggests. And bring the submersible pump inside: it can hold water in its body and be damaged by frost even when the tank is empty.

Vans with an on-board fresh water tank have the advantage. On-board tanks are much less likely to freeze, and the Camping and Caravanning Club calls an on-board tank ideal for a frost-free supply. 12-volt tank heaters exist too, but they can flatten a leisure battery if left on for long, so they are best used on hook-up.

Some vans have an automatic frost control valve on the hot water boiler. It opens at about 4C and dumps the boiler, and usually the water tank with it, the Camping and Caravanning Club explains. That protects an expensive boiler if you forget to drain down, but it is maddening to wake up to an empty tank on a cold morning. On some systems, keeping the boiler switched on at its lowest setting stops the valve opening, the club adds. Check your van's handbook for how yours works.

A frozen waste tank is the problem you can't fix until the weather changes. Waste water in an external tank will eventually freeze in a hard frost despite good insulation, and then you can't drain it. For motorhomes and campervans, the Camping and Caravanning Club's advice is to leave the waste valve open and drain straight into a bucket, because frozen waste is far easier to deal with in a bucket.

Pipes can freeze too, wherever a run dips under an axle and water lingers. A little salt water poured down the drain before bed can help, since salt water freezes at a lower temperature. For the waste container itself, the Caravan and Motorhome Club suggests insulation, a low-powered electric heater or salt.

If you use anti-freeze, use a glycol-free caravan and motorhome type, which can also stop the toilet freezing. Never use glycol-based car anti-freeze: it can't go into the drains, the Club says. Toilet additives and rinse aids freeze at about the same temperature as water, so store them inside.

Propane is the gas for winter, because butane stops working near freezing (there is more on that in propane or butane). Heating that moves warm air or hot water around the van gives more even warmth than a single heater and helps avoid the cold spots where condensation forms, the Camping and Caravanning Club says.

Cab windows are the weak point on a motorhome or campervan: a big single-glazed windscreen loses a lot of heat. External screens that fit snugly around the glass work better than loose internal ones, which let warm air reach the cold glass and cover it in condensation. Good ventilation and heating are the best defence against damp. Keep the vents open even when it is cold, and expect mattresses to collect moisture, because people give out water overnight.

Cold slows a battery's chemistry and reduces its capacity. Without hook-up, start with a good, fully charged battery, and for longer stays think about a generator or a second battery of the same type, capacity and age as the first, the Camping and Caravanning Club advises. A caravan motor mover uses a lot of battery that the car's alternator is unlikely to replace on a short tow.

The simplest fix is a site with hook-up for the coldest nights. The Winter Campsite Index lists the sites that say they stay open all winter, with a hook-up column.

A closed-up van with the heater running all evening is exactly where carbon monoxide becomes a risk. The NHS lists gas heaters and cookers among the appliances that can produce it if they are faulty or poorly maintained, and it has no colour or smell. Fit a carbon monoxide alarm that sounds loudly, have gas appliances serviced by a qualified, registered engineer, keep the vents open even in a frost, and never use a camping stove or barbecue inside. There is more on gas in propane or butane.

Winter touring starts on the road. In ice and snow, stopping distances can be ten times greater than on dry roads, even on treated roads, the Highway Code says. Drive slowly in as high a gear as you can, and accelerate, brake and steer gently. Before you set off you must clear snow and ice from every window, keep your lights and number plates clean, and clear any snow on the roof that could fall on other people. If there is a warning for ice or snow, the Highway Code's advice is not to drive unless your journey is essential.

A tall van catches a crosswind, so on an exposed road in a gale, slow right down. Plan the drive for daylight, arrive at the site before dark, and leave the steep lane over the pass for another day if the forecast turns.

Before you set off for home at the end of a winter trip, drain the fresh and waste water systems so the van can't be damaged by frost in storage, the Camping and Caravanning Club says. Drain everything your van's handbook lists, boiler included. Water left in a system is what the frost breaks.

The same club's driving checklist for winter is short: have the vehicle serviced regularly, make sure the engine cooling system has the right amount of anti-freeze, use a stronger windscreen washer mix and carry a scraper and de-icer, check your tyres, and have breakdown cover that suits a caravan or motorhome.

You will know you have done it properly the first time a hard frost arrives while the van is parked, and you sleep straight through it.