Rain Tank Water

In the diagram below we see a water tank situated on a flat standard block. Not much to it is there.

Bit more to it than you can see but there are a few things to consider:

* Where to put the tank.
* Where to pick up the water from the down pipes.
* Where does the overflow go?
* How big the pump? (if needed)
* Where to put the pump.

There are other technicalities to consider but the plumber will put you straight there. (Hopefully.)

Where to put the tank.

Where it can’t be seen! Easier said than done. I have shown it at the back of the block in the corner. Easily screened and takes up the least amount of room. This of course brings up other complications. The corner of the block may be a long distance from the house and the pickup points for the roof water. Other types of tank (flat) are usually placed somewhere against the house and are also usually at the side of the house where they cannot be seen. These types of tanks are normally of a smaller capacity (2000 – 5000 liters or 450 – 1100 gallons). Water is very heavy so the tank should be placed either on a concrete base or a firm crushed gravel bed that extends beyond the boundary of the tank bottom.

Where to pick up the water from the downpipes?

Most down pipes go to a common junction point and then out to the storm water drains, these usually run along the street or sometimes are an easement at the rer of your block. This junction point would need to be located, broken and then a pipe laid from it to the tank. The diagram shows all down pipes going to the water tank. This would be probably only required if it was a large capacity tank (22,500 liters or 5000 gallons and up) For smaller tanks only one or two of the down pipes may be required.

Where does the overflow go?

This goes back to the junction point and reconnects to the storm water drain. Obviously this would be laid at the same time as the pipe from the down pipes to the tank.

How big a water pump?

In general not a very big one is needed if one at all. This depends what you are going to use the water for. If you are just going to use it for garden water maybe not but if you are going to supply the house it is quite probable that you will need one to provide a constant pressure. Often you may even see specials for water tanks that include a pump. The main thing is that it should be a constant pressure pump. That is, it is a pump that has a bladder under pressure that ensures the water is delivered at a constant rate.

Where to put the pump.

Once again where it cannot be seen but will need to be near a power point as most water tank pumps are electrically driven. If your house is elevated put it under the house but make sure it can be got at if servicing is needed. My pump is under my veranda and in 10 years have not had to get at it for servicing. Needless to say the pump should be at the house end of the pipe not close to the tank. If your house is not elevated it should be somewhere under cover.

The above are the basic things to think about if considering putting in a water tank on a straightforward block. If you just want a tank to water the garden then things are simpler. You don’t have to worry about pumps or pipes to the house you just need a tap on the tank unless you were considering using sprinklers then you would need a pump.

Now what if my house is on a sloping block? Well blocks slope two ways, down to the street or down from the street each having unique requirements. Visit my website where you can read articles on these types of tank installations.