The secret of achieving lush, healthy lawns and bountiful gardens is thorough, careful watering which encourages deep, drought-resistant roots. A sprinkler system is a convenient way to water the lawn and it also makes an efficient use of water.

Types of Sprinkler Systems:

The water pressure in most residential systems is not enough to water an entire lawn at a time. Therefore, most systems are divided into circuits each having its own control valve. Control valves are operated by an electronic controller that turns each circuit on and off according to the set schedule.

Sprinkler systems consist of PVC pipes running from the existing water supply line. The pipe connects to a riser that feeds the sprinkler head. Sprinkler heads are designed to throw water in full circles, half circles or quarter circles. They are of two types: Rotary sprinkler heads (extending above the ground permanently) and Pop-up sprinkler heads (designed to be flush with the ground when switched off therefore mowing over them is possible).

Planning a Sprinkler System:

1. Determine the water pressure and flow rate. Attach a water pressure gauge to a hose bibb. Turn the water on full to find the pressure. Although systems vary a minimum of 20 pounds per square inch (p.s.i.) pressure is needed to install sprinklers.

2. Check the flow rate by placing a 1 gallon bucket under a hose bibb. Turn the water on full and check the time it takes to fill the bucket. Divide the number of seconds by 60 to find the gallons per minute (g.p.m.) capacity of the line and this test will determine the size of each sprinkler circuit.

3. Plot the locations of sprinkler heads and multiply the throw distance of the heads (usually 15') by 1.4 to find the spacing between sprinkler heads so that the areas covered by each head should overlap.

4. Lastly, divide the system into circuits. The instructions leaflet includes an output chart that gives you a gallon per minute rating for each sprinkler head. Divide the gallons per minute capacity of the water line by the rating of each head to find the number of sprinkler heads that can be put on each circuit. Do not combine two different types of sprinkler heads e.g., lawn sprinklers with low-shrub sprinklers on the same circuit.

5. Use 3/4" PVC pipe to lay a system with circuits that are less than 100' long and use 1" PVC pipe for circuits over 100'. In both cases, the system pipe will not be larger than the supply line that is tapped into.