Understand Your Pool Filter Pressure Gauge 

Your pool filter has a big job to do, and that is cleaning your water.  It also has a little friend called a pool filter pressure gauge.  This piece of equipment that sits on top of your filter alerts you of any potential problems with your filter.

We should take care of our pool filter so it can operate at peak performance.  And here, we'll start with one of its most important components, which is the pressure gauge.

Understand Your Pool Filter Pressure Gauge

What Is a Pool Filter Pressure Gauge?

A pool filter pressure gauge is the dial located on top of your pool filter.  Its function is to read the amount of pressure inside your filter.  It's populated with numbers around the perimeter and has indicator arrows, or needles are they're sometimes called, that move up and down so you'll know the pressure inside the filter.  These arrows determine whether we have normal, high, or low filter pressure. 

The range for a pool filter pressure gauge is 0 psi (pounds per square inch) to the highest of 60 psi.  

What Is Normal Filter Pressure?

Pool filter systems can be different.  What's normal for one pool might not be normal for another.  All filter systems can operate a little differently.  This can be based upon many factors such as the size of the filter, the pump motor, plumbing, and how dirty the filter is, among other things.  However, there are some consistencies throughout the pool world.  

I've found that normal pressure for a home pool should be between 5 psi  - 10 psi.  This is considered average and would be your "clean filter" pressure.  You should check your pool filter pressure gauge each time to backwash to ensure it's properly working.

You can also check with your pool filter's manufacturer, owner's manual, or ask your pool professional to find out what’s considered normal for your filter model.

Easy pool maintenance

What Is High Pressure? 

When your pool filter pressure gauge reads 8 - 10 psi over your "clean" or "just backwashed" pressure, it's time to either clean your filter or backwash.  Rising pressure in your pool filter is normal and expected.  For most filters, anything over 20 - 30 psi would be considered high and would need to be addressed immediately.  Pool filters are under tremendous pressure during normal operating cycles, and having too high filter pressure is not good. 

If after cleaning or backwashing your filter, and the pressure doesn't come down, it might be time or either replace the filter media or the pool filter pressure gauge. 

What Is Low Pressure? 

When your pool filter pressure gauge reads 5 psi or under, chances are you have low filter pressure.  Low filter pressure can have several causes.  Most of the time they're easy to fix.  Low pressure normally means the pump motor is not drawing enough water from the pool.  Make sure your bottom drain cover is clear and the water level is correct, which is 1/3 - 1/2 from the bottom of the skimmer. 

Next, keep the skimmer basket cleaned out and check the skimmer weir to ensure it freely moves.  Then we move on to your equipment.  Check the O-ring on the pump pot lid and replace it if needed.  Cavitation in your pump pot is an indication of low pressure.  This is when the water goes up and down and churns all around.  Clean out the pump basket, all debris from the pump pot, and check the impeller for debris and clean it out if needed.

The most common cause of low pressure is a blockage before the pump motor.

When To Replace Your Pool Filter Pressure Gauge

You've checked for leaks, cleaned out the skimmer and pump basket, backwashed, and did everything you should do.  It seems your pool filter pressure gauge is still acting up, or not acting normally.  It might be time to replace it.  Before you head out to the pool store, I want to share with you a cool trick I've been doing for years to test a filter gauge.

Turn the pump motor off and watch to see if the black needle drops to zero.  If it does, your gauge is probably still good.  If the needle sticks when the motor is turned off, or doesn't go all the way to zero, it might be time to replace it.

Another reason is simply age.  I always check the pool filter pressure gauge during my pool inspections.  Many times the needle is still working, but the plastic shield in the dial is simply worn out, or bleached from the sun.  This makes is difficult to determine the right psi.  When I see this, I make a note of it in my report and recommend replacing the pool filter pressure gauge.  Other times the gauge will need to be replaced is if it's broken, rusted, cracked, or the plastic shield is missing. 

Understand Your Pool Filter Pressure GaugePool filter pressure gauge starting to bleach out

Be A Pro At Gauging Your Gauge

The pool filter pressure gauge an important part of your filter.  Remember to inspect it each time you backwash.  Use the information above to determine whether or not your filter gauge is properly working, otherwise, the equipment could be damaged and you could have costly repairs in the near future.