water degradation

Hi Thomas A

So long as it is in the dark so not algae can build up (and it is) it lasts for ever. We don't drain our tanks, even if the van has been left sitting for two years. Likewise our home water tanks which just get topped up with the rain. For those using water from underground sources (which is part of many city supplies) that has been sitting underground for tens of thousands of years. All good water.

Capacity? Depends what tank you have fitted. Ours have 80 litre; some tanks are 60, some 100, and probably many other sizes. I think our first caravan had around 20 litre tank.

Motherhen

I agree that in a black poly tank the water will stay potable for a very long time but it may absorb some taint from the plastic. So to be sure, I drain and refill ours prior to each trip.

No worse than every rainwater tank on a house, possibly better as the residual chlorine introduced when filling from the tap may provide some help for a short period of time.

Andrew