Understanding Your Pool Filter Pressure Gauge

Written by Michael Dean
December 14, 2023

pool filter pressure gauge next to a swimming pool

In addition to routine cleaning and proper chemistry, your pool filter is one of the first lines of defense in a swimming pool. The pool filter pressure gauge is an instrument that indicates how well the filter is performing. A filter pressure gauge can provide a first clue that there may be a problem with your filtration system before there is any significant damage to the entire system.

In this article, I will help you understand your pool filter pressure gauge and provide tips on what to do when the pressure is too high or too low and how to replace a worn pool filter pressure gauge.

Main Takeaways

  • A pressure gauge measures the amount of pressure in your filtration system.
  • In general, a pressure reading between 10 to 25 psi is considered normal. If your pressure gauge is reading 10 psi above the normal range, your filter pressure is too high. If it’s 5 psi below the baseline, the pressure is too low.
  • Inconsistent pressure readings, even after your pool has been maintained, mean something may be wrong with the gauge. Other signs that indicate a pressure gauge may need replacing include visible wear and tear.
  • Most pressure gauges are mounted directly on top of the pressure release valve, which releases the air trapped in your filtration system.

What is a Pool Filter Pressure Gauge?

A pressure gauge is an instrument that measures the amount of pressure in your pool’s filtration system. Monitoring pressure gauge readings can let you know when it is time to clean or replace the filter or possibly even replace other plumbing components.

A pool filter pressure gauge measures pressure in pounds per square inch, or PSI. It measures the pressure in a liquid, such as your swimming pool water filtration system. The gauge is typically round with little marks and numbers to indicate different amounts of pressure and a needle indicator.

What Should the Pool Filter Pressure Gauge Read?

An optimal pressure reading for your pool’s filtration system depends on several factors. The size of your pool, the size of your pump, and the condition of your pool water directly impact pressure readings. Generally speaking, a pressure reading between 10 – 25 psi can be considered normal.

Once you have installed a good pool filter, turn everything on and take a baseline reading. Take a new baseline reading each time you change your pool filter. This reading, taken when everything is operating as it should, will give you a target to aim for as an optimal pressure reading for your pool.

Check your pool’s pump pressure at least once per week. It may be a good idea to record readings so you can easily see trends and correct them before your pool water suffers.

What to Do If Your Pressure Reading is Too High

Consistent pressure readings that are ten psi or higher over your baseline indicate that your filter pressure is too high. Put simply; this means that your filter is dirty or clogged and needs attention. Depending on the state of the filter, you may be able to clean it out to restore optimal pressure levels.

Most cartridge filters last 3-5 years. However, if you are continuously cleaning it or experiencing high-pressure readings more often than every six months, it is time to replace the filter.

Pool cartridge filters are made out of a polyester material called remar. It looks like a thick paper material accordioned between two plastic end caps. Over time this material will get clogged with dirt and debris to the extent that a good hose down is no longer sufficient. Or, as the remar material wears out, the filter will begin to show flat spots, another sign of wear and tear that lessens its efficiency.

What to Do If Your Pressure Reading is Too Low

A low-pressure reading means water is not flowing into your filter fast enough. This can be due to a clog or leak in the system before the water reaches the filter. The various parts that feed into your pump, like the skimmer, drains, and baskets, are all likely culprits.

For any pressure reading that is five psi or higher below your baseline, inspect your entire filtration system for debris creating a blockage or parts in disrepair. Clean your skimmers, baskets, and drains, and recheck the pressure reading.

If low-pressure readings persist, a more severe issue with a leak in your filtration system may be slowing it down. If you can locate the leak and fix it yourself, you can be back in business with minimal effort and expense. However, if you can not, you can expect to spend some money on a professional repair or pump replacement.

How to Know When it is Time to Replace your Pool Filter Pressure Gauge

Before you go into the trouble of making a significant and expensive repair, verify that the pressure gauge is functioning correctly. Like any other piece of equipment, it can break down and fail. Inconsistent pressure readings that seem all over the place or persistent low or high readings, even after your pool has been thoroughly maintained, are signs that something may be wrong with the gauge.

Is there any visible wear on the gauge, such as a cracked glass face or corroded fittings? Does the needle move quickly? Or does it seem loose or sticky? If the indicator appears worn, it is probably time for a replacement. It is much easier to replace a lousy gauge than to chase a non-existent pressure problem.

What is a Pool Filter Air Pressure Release Valve

In addition to the pressure gauge, your pool filtration system is outfitted with a pressure release valve. Most pressure gauges are mounted directly on top of this valve. This valve provides a mechanism to release the air trapped in your filtration system.

Air can become easily trapped inside your pool’s filtration system by opening baskets and backwashing filters. Over time, the trapped air can build up pressure that affects the overall performance of your filtration system.

Steps to Easily Replace a Worn Pool Filter Pressure Gauge

If you are the lucky owner of a worn or faulty pool filter pressure gauge, rest assured that replacing this part is pretty simple. Even modestly handy individuals can tackle this as a DIY project.

  1. Turn off your pool pump. Do not risk damaging a more expensive piece of pool equipment or risking electric shock. Before you begin, make sure that power to the pump system has been shut off.
  2. Release pressure. Open the air relief valve to release the pressure before attempting to dismantle to avoid injury and make it easier to remove pieces.
  3. Loosen the pressure gauge by turning in a counter-clockwise direction with a wrench.
  4. Remove the old pressure gauge from fitting.
  5. Clean the area thoroughly.
  6. Wrap three layers of plumbers tape on the threading of the gauge and place it into the fitting.
  7. Hand-tighten the new pressure gauge into the fitting. Finish by tightening with a wrench until secure.
  8. Turn on the pump and release the air pressure valve.

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The Takeaway on Pool Filter Pressure Gauges

A pool filter pressure gauge is an essential part of your pool’s overall filtration system and water health. The pressure gauge indicates how well your filtration system works and helps identify problems early.

Understanding that an ideal pressure measurement is specific to your pool setup, you should establish a baseline reading with a fresh pump, clean filter, and clean water. Once you know your standard, you can check your pressure gauge weekly to determine if the pressure is within normal ranges, too high, or too low.

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