The water for the home is delivered through either a large capacity city water main, a well, or pumped from a nearby lake or pond.
City water supply systems have a water meter attached to the system to measure the volume of water usage to the home. Many but not all city water irrigation systems also have a second water meter to measure the water usage to the irrigation system itself. This is useful because it reduces the cost associated with city water supply and also helps to identify the water source (irrigation or home) if there is a suspected leak.
A system shut off valve is installed which allows the homeowner to shut off the water to the irrigation system without affecting the water supply to the home. This can be helpful when working on an irrigation component to the system which is under pressure or in the case of an emergency that requires you stop the water flow.
Because the connection to the irrigation system is also connected to the water coming into the home, there could be the potential for accidental contamination. To prevent this, a backflow prevention device (Pressure Vacuum Breaker PVB/Backflow Preventer) must be installed on every system. It stops irrigation water from draining back into the main supply line. Local building codes will dictate the type of PVB that must be installed.
After the water flows through the backflow prevention device, it is held under pressure behind the sprinkler system valves. When the valves receive a low voltage electrical current from the irrigation controller, the valves open allowing water to flow through to the sprinkler heads and onto the plant material to be watered.
