How to Plan Your Sprinkler System

How to Plan Your Sprinkler System

An underground sprinkler system is the most efficient way to use water beside from being the convenient means of watering your lawn. This article will discuss how to install a sprinkler system and provide an overview involved in designing and installing the water system.

The article will cover information on:

• Sprinkler Systems and its types
• How to plan your Sprinkler System

The Types of Sprinkler Systems:

The pressure in most residential water systems is not typically strong enough to water an entire lawn at an instance. Because of this, most sprinkler systems are divided into circuits, having a control valve on each circuit. The control valves are operated by an electronic controller unit that is set to turn on and off each circuit according to programmed schedules.

The system would consist of standard PVC pipe running through your lawn from a water supply line. On each sprinkler, the pipe would connect to a riser that feeds the sprinkler head. Each sprinkler head is designed to throw water either in a full circle, a half circle, or a quarter of a circle. There are actually two types of sprinkle heads, the rotary sprinkler head which extends above the ground permanently and the pop-up heads that are designed to be flush on the ground when off, for lawn mowers to pass over them.

Planning your Sprinkler System:

1. First, plan your system and check with your local building department and secure permits that you may need. Make a rough sketch of your property, indicating the location of all structures, driveways and pathways, including the shrubs and trees. You can then call your local utility companies and have them come out and mark the location of electrical, buried gas, and telephone lines. Include these markings in your sketch.

2. Secondly, determine your flow rate and water pressure. You can either borrow or rent a water pressure gauge and attach it to a hose to measure the water pressure. Once the gauge is in place, turn off all the water in the house. Then open the valve for the hose in full. Sprinkler systems vary, but typically, you may need a minimum of 20 pounds per square inch (psi) pressure to have sprinklers.

3. You can check the flow rate by filling a one-gallon bucket with a hose, but turn off water in the house, and record your time on how long it takes to fill the bucket. Then calculate by dividing the number of seconds by 60 to find the gallons per minute (gpm) capacity of your line. This test will actually determine the size of each sprinkler circuit.

4. You now can plot the locations of your sprinkler heads on your sketch. You then multiply the pitch or throw rating distance of the heads (basically @ 15 feet) by 1.4 and find the space in between sprinkler heads. There will be overlapping between heads to cover all areas. In some windy areas, you can space the sprinkler heads according to its throw rating.

5. Finally, you can divide the system into circuits. Sprinkler heads have manufacturer’s instructions that include an output chart and its required gpm rating. Calculate by dividing your gpm capacity by the rating of each head to find the number of sprinkler heads that place in each circuit. Do not attempt to use different types of sprinkler heads for instance, lawn sprinklers with low-shrub sprinklers, on a single circuit. They would require different flow ratings.

6. As a rule, you will use a 3/4″ PVC pipe to lay a system with circuits that are less than 100 feet long, or a 1 inch pipe for circuits over 100 feet long. In most cases, your system pipe shall be no larger than the supply line are tapping into. Reduce the size of your sprinkler system pipe.