Thanks Guys,
One of the reasons I ask is that my water pressure is quite low & I only make about 400 litres in a 24 hour period. Couple that with the problems I have had with my IBC tank, it means I can't store more than about 500 litres at any given time unlessl I replace my tank.
I think my problem is I've got sick of forking out money for bits & bobs. If I bought a pump to increase my water pressure & replaced the IBC tank I could build up a nice store of water just in case, but those 2 things would set me back another £150 plus & I can't justify it at the moment.
So I'll just carry on 4 the time being & hope I have enough for each day.