How Many Sprinkler Heads Can Be on One Zone?
To answer how many sprinkler heads you can use per zone, you need to know in the first place how much water is available for irrigation. By measuring the water pressure and maximum flow rate, you’ll know the amount of water each zone is able to handle for optimum output. In this article, you’ll learn how to do so. But first, take a look at the advantages of dividing the yard into zones.
Zoning the Lawn
Unless you have a small yard, it’s very possible that you’ll need more than just one zone of sprinklers to efficiently irrigate your lawn. Considering that not all the plants in your garden require the same amount of water, establishing irrigation zones will help you program the sprinkler system accordingly and provide good coverage.
Start by making a plan. Divide the yard in such a way, so you separate the plants according to their type, including their watering needs. For instance, the grass should be watered separately and more frequently than shrubs and trees. For this reason, it’s of utmost importance to choose the right sprinkler heads for your yard as well. Then, figure out the total number of sprinklers you’ll need and the location to lay them out, depending on the water pressure, their spraying range and pattern.
Measure the Water Pressure
Water pressure is the measure of the force that gets the water through the plumbing system. At different pressures, the sprinkle distributes different amounts of water. In general, sprinkler systems are designed to operate on pressures of around 30 PSI. To measure the water pressure in your house by yourself, follow the steps below:
- Hook up a pressure gauge on the faucet nearest the water meter.
- Ensure that there are no open taps and faucets in the house.
- Turn on the faucet and read the pressure on the gauge, which is measured in pounds per square inch (PSI).
Measure the Water Flow
The water flow rate is the amount of water a system distributes over a specific period of time. The easiest way to get an accurate measure of the flow rate in your house is to measure the time a bucket takes to fill up.
- Get a 5-gallon bucket.
- Check if all other taps and faucets inside and outside your house are closed.
- Turn on the tap and record the time it takes, in seconds, for the bucket to fill up.
- Calculate the water flow rate, using the following formula:
For instance, it takes 28 seconds to fill the bucket, and therefore 5 / 28 * 60 = 10.7 GPM.
Now, you need to know the required flow rate of each sprinkler to operate as well. With that said, if you have a sprinkler that uses 2.3 gallons per minute, you can put 4 of them on a zone, seeing that 10.7 / 2.3 = 4.6.
However, make sure not to exceed the capacity of the zone. Speaking of which, if the calculation comes out even, put one sprinkler less. The water flow in your house isn’t restricted, whereas that to the sprinkler is. Therefore, given that you measure 12 GPM, and have sprinklers that use 2 GPM, put 5 of them instead of 6.
Water pressure and flow are correlated. Water flow refers to the amount of water distributed in a certain amount of time and is determined by water pressure. On the other hand, water pressure refers to the force that pushes water through the plumbing system. Therefore, the higher the pressure, the greater the flow of the water.
The pipes of residential sprinklers are either 1″ or 3/4″ in diameter, and each of them has restrictions on how much water it can distribute safely. With that said, the best water pressure for a sprinkler system to operate is between 30 and 50 PSI, which will result in even spray-patterns and water efficiency.
A sprinkler system won’t operate as supposed to when the water pressure is low, which will result in dead patches of lawn. To increase the pressure, detach a few sprinklers from each zone and close the pipes. Then, install a booster pump on the main water line.