how to determine normal system pressure for your pool


Well-known member
Jan 18, 2016
Tucson, AZ
I have a Pentair VS system with sand filter for a 21k inground pool with in floor cleaning. The in-floor runs 3-4 nozzels at a time. I also have rooftop solar.

Since the pool was new, if the VS is running full tilt (pool high or spa activated) my system pressure measured at the sand filter is about 30psi. This has always seemed high to me, but I don't know. I know all systems run at different pressures but does this seem out of the ordinary? I can always tell when my filter needs to be backwashed, because the spa therapy jets won't pull air anymore, at this point my system pressure is 35psi.

What are your thoughts?


Bronze Supporter
Apr 27, 2018
Midland, MI
If you take a look at my signature, my pressure/psi runs at 15. 35psi seems a bit high, but I'm no expert. When you backwash your filter, does the psi/pressure go down and if it does, what is the number you get? I know the baseline of my psi is 15 and I usually backwash when my pressure goes up 20-25% above my baseline.


Gold Supporter
TFP Guide
Jul 21, 2013
Northern NJ
Pool Size
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
Normal system pressure depends on what equipment is in the water flow. Having details of your pool in your signature would let us better comment. Solar or heat pumps create more pressure because they restrict the flow of water. IFCS is also high pressure. So you have a bunch of things that raise your system pressure.


LifeTime Supporter
TFP Guide
Jun 12, 2011
I also have an infloor system and solar. When the pool was new, it had a 2hp single speed pump and the pool ran a baseline of 30 psi. Now I have a VS pump and run lower pressures. To establish a base line for determination of when to clean filters you must make sure you always use tha same settings. Pressure varies as the infloor goes through the various zones, so I bypass the infloor and set it on pool return. My current baseline pressure is based on 2600 rpm, solar off, infloor bypassed, both skimmers and main drain intakes open, with a freshly cleaned filter. That gives me 20psi. So to check the state of the filter, I use those settings. If I get any reading approaching 25psi, it’s time to clean the filter.

My spa has a separate pump, so my main pump (a VS) never needs run above 2600rpm. If it were my pool I think I would add an air blower to the spa and reduce the pump speed.
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