Thread: Inadequte water pressure when sprinkler system on

My water source is a well, which works fine with the exception of running the sprinkler system. With the sprinkler system on the pressure is low and we don’t get the lawn coverage we used to. The key info: well is 159 feet, static water level is 108 feet, pumping water level is 140 feet, pumping rate is 11.7 GPM (all measured 2 ½ years ago. Submerged pump is Sta-Rite ¾ horse 10 GPM, motor is ¾ horse Franklin both of which were new 2 years ago along with a new check valve and pressure switch. The bladder of the pressure tank is charged 33 PSI, pump switch is set for on at 35 PSI and off at 55 PSI. It takes 68 seconds to pump the tank from 35 to 55 (up from 56 seconds 14 months ago). When the sprinkler system is on the pressure drops to 24 – 26 PSI and stays there (pump running continuously). As the sprinkler system seemed to work OK up to this year, I never looked to see what the pressure with the sprinkler on was in the past, as coverage seemed OK.
Any ideas? Appreciate the help.

With the pump etc. being new, I would look to the well. Does your well have a screen or is it a rock well? If it has a screen, the screen is probably plugging up. If not, it could be the water level. I'm not sure what the pump is capable of at that pumping level, but I wouldn't think it would be too good.

bob...