What Is a Normal Pool Filter Pressure Range?

Written by Michael Dean
March 19, 2024

pool filter pressure gauge with question mark

You know the pool filter is the heart of your swimming pool, so it’s important to know when something is not quite right with the filter. One way to ensure this is to keep an eye on the pool filter pressure range.

In this article, I will go over what a normal pool filter pressure range is and any causes and fixes for high or low filter pressure and other common pool filter issues. Let’s get into it!

Main Takeaways

  • A normal pressure range can be around 10 to 20 or 5 to 15 psi, depending on your filter.
  • You have high filter pressure when the gauge reads 10 psi above the normal range and low filter pressure when the gauge reads 5 psi below the normal range.
  • High and low filter pressure can be caused by a variety of issues, including a dirty filter, faulty valves, issues with the return jets, too-low water levels, air leaks, clogged skimmer baskets, and more.
  • In some scenarios, the pressure gauge itself might be the problem, in which case, you may need to replace it entirely.

What Is a Normal Pool Filter Pressure Range?

The normal pressure of a pool filter usually falls between 10 and 20 or 5 and 15 psi (pounds per square inch). That might sound like a broad range, but this is because optimal pressure for your specific pool system depends on several factors: the size and type of filter, the specifications of your pump, the plumbing design, and the overall condition of the pool equipment. Essentially, what is “normal” for you may not be “normal” for another pool owner.

Ultimately, while I have provided the general range of filter pressure, I strongly recommend taking consistent readings of the pressure for your pool to establish your normal range so that you are better equipped to deal with any filter issues that may arise. High or low filter pressure are fairly common issues pool owners have with their filters, and with this knowledge in hand, it’ll be easier to act quickly when changes in pressure suddenly occur and will make it simpler for you to identify potential concerns.

Causes and Fixes of High Filter Pressure

Generally speaking, you are dealing with high pressure in your system when the gauge reads 10 psi above the normal range. High filter pressure in a pool system is a symptom of varying issues. But one thing is for sure: you’ll need to address the root cause of the problem to ensure your pool continues to function correctly. So, what are the common causes and fixes of high filter pressure?

Dirty or Clogged Filter

When debris and contaminants build up in the filter, they can restrict water flow, leading to increased pressure.

How to Fix

The fix is pretty simple. Backwash the filter and/or clean it to clear out the accumulated debris and keep the pool clean to reduce the load on the filter. If necessary, replace the filter media (such as cartridges, DE, or sand) if they’re too worn out and need replacing.

Faulty Valves

In some situations, the valves in the pool plumbing system might be closed or may even be damaged. This causes undue pressure on the filter, leading to a higher reading on the gauge.

How to Fix

Check the diverter valves. Are there any visible signs of damage? If so, replace them. Are they fully open? Ensure the diverter valves are fully open, allowing water to flow freely through the system to the return lines.

Various Pump Issues

Every now and then, I come across a pool owner who had previously installed a pool pump that is too undersized for the pool’s needs. Alternatively, the pump might malfunction due to rust build-up or a failing impeller. If the pool pump is not running as efficiently as it can, the pool water will not circulate the pool efficiently, causing increased pressure over time.

How to Fix

Remove the pump from its housing and examine it for any signs of damage or malfunction. If the pump is undersized for your pool, you must upgrade it to a more appropriately sized model. Here’s my pool pump size calculator to help you determine whether or not you need a bigger pump.

Closed or Undersized Return Jets

If your return jets are closed or partially closed, this will inevitably lead to resistance, which causes an increase in filter pressure. Another issue you may have with your return jets that may lead to high pool filter pressure is that your return jets are not big enough.

How to Fix

Check the return jets. Are they fully open? If not, open them to allow water to flow and release the high pressure within the system. If your return jets are too small, get larger ones!

Issues with the Pressure Gauge

Sometimes, the problem can lie with the pressure gauge itself and has nothing to do with the pressure in the filtration system at all! The pressure gauge might be malfunctioning or inaccurate, offering false readings.

How to Fix

If you suspect this is the issue, recalibrate the pressure gauge. If the issue persists, you’ll have to consider replacing it with a new model.

Causes and Fixes of Low Filter Pressure

If your filter pressure gauge is indicating pressure that is 5 psi below the base range for your pool filter pressure, you are dealing with low filter pressure. Low filter pressure in a pool system generally indicates issues affecting water circulation and filtration efficiency. Here are the different causes and fixes of low filter pressure.

Air Leaks in Suction Lines

When air enters through the suction side of the system, there will be a reduction in pressure.

How to Fix

You’ll need to inspect the suction lines for possible air leaks and pressure test them. This also means you’ll need to check the pump lid, valves, fittings, and any O-rings. Seal or replace leaks you come across.

Clogged Skimmer Basket

The skimmer basket catches the larger debris that may fall into your pool and your filter, such as leaves, twigs, and even the occasional creature like a frog! If your skimmer basket is filled to the brim with debris, it can obstruct water flow and decrease pressure.

How to Fix

Check the skimmer basket. Is there any accumulation of debris? If so, empty it and prevent future build-ups by regularly cleaning the skimmer basket to ensure a healthy flow of water. Generally, you should be checking and emptying your skimmer basket at least once a day!

Faulty Pump Impeller

Check the pump impeller. Is it not moving freely? Is it rusty? Is there some debris blocking its movement? All these issues can lower the pressure range of the filter.

How to Fix

Disconnect the power, open up the pump housing, and have a peek inside, locating the impeller. Clear any obstructions that may be stopping the impeller from turning properly and replace the entire impeller if necessary. Then, reassemble and test to ensure it is working normally.

Water Level Too Low

Another common cause of low filter pressure is a water level that is too low. The water level of your pool should ideally be halfway up the skimmer opening. Too high, and the debris won’t properly flow into the skimmer. Conversely, too low, and air will be sucked into the system, which may cause the pump to lose prime and cause low water pressure.

How to Fix

Is the water level within the recommended range? If not, refill the water in the pool with a garden hose and adjust the water chemistry to maintain continued pump and filter efficiency.

Other Common Pool Filter Pressure Issues

Low or high filter pressure isn’t the only issue pool owners might run into when it comes to their pool filter pressure. Here are some other common issues you may come across:

Stuck Gauge

Sometimes, the pressure gauge might be stuck on a single reading—possibly due to rust, internal damage, or dirt.

How to Fix

Try gently tapping the gauge on the side with a small hammer if you suspect it is stuck. If there is no response to this or any kind of alternative pressure, you might have to replace it entirely.

Fluctuating Pressure Readings

The pressure gauge might have rapid fluctuations in readings, suddenly going too high or too low. This can occur due to changes in the water level, air in the system, or a faulty gauge.

How to Fix

Verify the accuracy of the gauge with one that’s reliable. If the pressure gauge itself is not the issue, inspect the equipment for air leaks—the skimmers, the suction lines, and the valves. If it’s not that either, check your water levels; they might be too low! If you’re still stuck with a fluctuating pressure reading, contact a professional for help.

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Under (Filter) Pressure!

Pressure isn’t always bad, at least not when it comes to your pool filter. But once you figure out your normal pool filter range, this can be a great way to watch your pool equipment and jump into action when the pressure reading is too high or too low. Try to take a reading at least once a week as a regular part of your pool maintenance routine.

Do you have any questions about pressure gauges or your pool filter? Drop me a message; I’ll be happy to help you out.

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