On 26/07/2013 09:57, Broadback wrote:

I have set up three rainwater butts, linked at the bottom. works quite
well but from time to time develops a leak in one joint or another. I
have been looking at larger storage tanks, but they seem ridiculously
expensive. Any suggestions?

I link mine with a siphon over the top. Much less inclined to leak that
way although no good in a cold winter as the pipes will freeze and it
fails with an airlock if ever the water level gets to low.

How big do you want it? The one built into my Belgian greenhouse was
made by a combination of 10cm thick cast concrete and was roughly 2m x
1m x 1.5m. It took the water from the greenhouse roof.

It was almost waterproof from the outset but had the odd annoying leak
from time to time hence eventually the need to line it with butyl.

Otherwise the next best might well be a scrapped single skin plastic
1500L oiltank recycled from a neighbour or new for about £300.

Worth asking on uk.d-i-y for better ways to do it with minimum effort.

--
Regards,
Martin Brown