Water

Our van's water tank holds 70** litres. There is also a separate "cistern" tank for the loo. Some folk don't like drinking water from the tank so they carry bottled water with them. We carry a few bottles of tap water in the fridge for use in an emergency (like an empty tank!) or when we want a really cold drink. We are happy to drink the water from the van tank. It is British mains water which is considered safe to drink after sitting in underground pipes for weeks on end, so a few days in the tank should not be a problem. 

Anyway we have never had any adverse effects. We add a capful of Milton fluid to the loo cistern and two capfuls of Tesco biological washing liquid to the loo tank. Much cheaper and in my opinion more effective than proprietary concoctions. We drain the complete system if the van will be spending any length of time at sub zero temperatures. We fill the van at home using a normal hosepipe before we set off. We carry some equipment to make it easier to keep it topped up when we away.

We have a long hose for when we can get close to a tap or standpipe. We also carry a collapsible 8 litre watering can, and a short hose so we can fill it from almost any tap (e.g. in public loos) and an extention to make it easy to pour the water into the van.

If we can park over a drain we empty the "grey water" (mainly dishwater and washing water). If we have no drain we see no problem with emptying it on grass or soil. We only empty the loo down a proper toilet, either at home or public loo.

Update One lives and learns. 

We bought six 5 litre bottles of still water for around £2 each from Tesco. We didn't really want the water - it was the bottles. We now head off with a "spare" 30 litres of water stored under a seat. This is enough for around a week. If we are away longer, filling up now means either the hose, (which we can hardly ever find a tap to connect in the UK) or filling up the bottles and emptying them into the tank.  The only extra was a flexible funnel to fit the fresh water inlet. 

 **70 litres according to the handbook - 50 litres measured!Under normal usage we seem to use an average of 10-12 litres per day so we can just stretch to a week with the extra 30 litres in the bottles.