Annual catchment maintenance costs

[Jay Bondesen]

I think that a 'first flush' component is a good addition too. You do need to think it through better than my builder did though since it isn't the easiest thing to do and it will cost you some water. Since most tanks are sitting out in the yard the plumbing runs to it on the ground and then up and over the sides and some tanks have six foot high sides. If all of this is done on flat ground then the pipes are always full of water up to that six foot elevation and could amount to many gallons of water. So the next rain just moves that water on rather than flushing out. You either need to start with empty pipes or flush right at the gutter outlet, or at least before the standing water level. I put in a T and thirty feet of pipe at the base of tha tank and put a valve on the end of that. The valve is usually just open a crack and lets the plumbing drain out after a rain but lets the flush water pass the tank inlet. I lose a lot of water each time because I have to refill all of the pipes before it goes into the tank but I have plenty of roof too. I can also leave it fully open when I, as some do, add a little bleach to the tank. With a tank full of treated water you don't really want excess rain running through the tank and out the overflow. (I think that Trish, in her catchment book, would agree that no standing water in your drain pipes is the preferred method.)

Jay