How to Measure Pressure
 Measure your homes water pressure by attaching a water gauge onto an outdoor faucet. Then turn off ALL the water throughout your home, including dish and clothes washers. Turn the outdoor faucet on all the way and note the psi reading. Repeat this process for all your outside faucet locations. Take several readings at each location throughout the day. When calculating your sprinkler output use the lowest reading.
The amount of water that moves through pipes at any given time is your flow rate. Flow rate is measured in either gallons per hour (gph) or gallons per minute (gpm). Sprinkler systems and drip emitters have designated output rates which are measured in gpm or gph. When you design your sprinkler layout you can put only as many devices to any given zone as your water supply can accommodate. If your irrigation design has a zone that requires a higher flow rate you can simply create break down that area into smaller zones. Flow rate is not as critical in drip irrigation because much less water is distributed.
How to Measure Flow Rate
To determine your flow rate you will need to fill a bucket with one gallon of water. Mark the inside of the bucket at the one gallon mark. Empty the bucket and place the bucket under your outdoor faucet. Open the faucet all the way while counting how many seconds it takes to fill the bucket up to the one gallon mark. To determine the flow rate divide the total number of seconds it took to fill the bucket up to the one gallon mark into 60. This will give your gallons per minute or gpm flow rate. A five gallon bucket will give you a more accurate reading of your flow rate. When using a five gallon bucket remember to divide the final result by five.
Every faucet that will be used for irrigation will need to be tested. Flow rates will vary between faucets because of location, diameter of the pipe, length and type of pipe. Select the faucet with the highest flow rate for the most circuits.
Adjusting Pressure Levels
Water pressure that is too high can cause sprinklers to mist or fog. You can purchase a pressure regulator or individual pressure reducing valves to fix this situation. Pressure reducing valves will restrain the force of the water to a sustainable level. Pressure reducing valves will also reduce the wear and tear on your equipment. You may want to contact a plumber if your water pressure is extremely high as this can be harmful for your interior plumbing fixtures too.
There are also rotors that come with check valves which can accommodate strong water pressure.
Water pressure that is too low is also a problem for a sprinkler system. To fix low pressure you can install a boost pump in your main irrigation line. A boost pump will increase the pressure enough to run your rotors and high-pressure sprinkler heads. To be efficient wire a a switch called a pump start relay to your sprinkler circuits that require high pressure. A pump start relay will activate the pump only when the the circuits are on. A drip circuit will usually work with low water pressure without the need for additional equipment. |
