The majority of Watering Systems get their water from a Water Board supplier. Running your system direct off the mains water (without a pump & tank) you should comply with your local Water Board regulations. Most Water Boards stipulate, a double check valve and a short length of hose (making a temporary connection) to be installed before any parts of your watering system. If you are having a tank installed it should be fitted with a class A air gap.
If you are having a tank or pump installed, you can collect rain water that falls onto your roofs. If you do any Rain Harvesting we would recommend you double the amount of water you store. This will increase the initial cost of the system but this will be off set by the water you collect. Rain water is clean and you are helping the environment.
Water from your shower, bath, kitchen sink, washing machine and dishwasher drains can be collected in a tank and recycled. We recommend a large tank and non-biological detergents.
As a statutory right, every residential property is entitled to 20m³ (4,400 Gallons) of water a day from the land with no charge for the water (you will need an electric pump for this). They normally cost in excess of £6,000 but when hose pipe bans are enforced by your Local Water Board, the ban will not apply to you. In addition, as the water is free you get the cost back over the years to come.
If you have a stream, ponds or brook in your garden you can use that water. Then you can either run the Watering Systems direct from the stream/brook or transfer it into a tank and then to your sprinklers.