How to Reduce High Pressure in Your Pool Pump System

Written by Michael Dean
April 3, 2024

pool pressure gauge showing lowering pressure reading

The filtration system is the heart of your swimming pool, so, as a swimming pool owner, you want to ensure you are monitoring it to the best of your abilities. One issue you might come across is high pressure in your pool. High pressure doesn’t only affect filtration but, in some cases, it may also cause filter tanks to rupture. So, when you get a higher pressure reading than normal, it’s in your best interest to reduce it as soon as possible.

In this article, I will cover why high pressure is bad before diving into the causes and fixes for high pressure in your pool system.

Main Takeaways

  • You have high pressure if the pressure reading is 10 psi or more above normal levels.
  • High pressure indicates an issue with the water flow and signifies an issue with the filtration system.
  • Some causes of high pressure include: dirty pool filters, suction air leak, oversized pool pump, and clogged breather tube.
  • There are various fixes for high pressure, according to the issue that is causing it in the first place.

What Is High Pressure?

I get many emails from pool owners asking about high pressure in pools, what it indicates, and, most importantly, how to reduce that pressure. Usually, pool owners want their problems solved easily so they can spend less time working on their filtration system and more time enjoying their swimming pool!

Pool filtration systems force dirty water into a filter, with clean, filtered water flowing out. The pressure pushes the dirty water through the filtration system, but there can be too much of a good thing where pressure is concerned.

Pressure levels can be monitored with the pool filter’s pressure gauge. Every pool system is different, so finding an exact number for “normal,” the number that has your filtration system running its best, is difficult.

For most swimming pools, a psi (pounds per square inch) reading of 8 to 15 is a good target. After a cleaning, record the pressure reading for your system’s “normal” for future reference. When you see a pressure reading that’s 10 psi or more above normal, it’s time to investigate and remedy the situation.

Why Is High Pressure in Your Pool Bad?

Usually, a high-pressure reading on your pool’s filtration system indicates a problem with water flow.

Since pressure pushes water through the filtration system, a higher pressure reading means the system has to work harder to get dirty water through the system. It can indicate blockages such as a dirty pool filter, lime deposits, or broken parts inside the filtration system.

Other reasons for high pressure are that your filtration system is trying to filter more water than it can handle or that there is a suction air leak.

High pressure in your swimming pool means your filtration is not working correctly. Eventually, the result will be improperly filtered water and possibly replacing your filtration system.

Consider a high-pressure reading warning bell that your swimming pool filtration system needs attention. Create the habit of checking your pressure gauge weekly as part of regular swimming pool maintenance, and you’re on your way to having a filtration system that’s always in top condition.

Causes of High Pressure and Quick Fixes

Several factors can cause high pressure in your swimming pool’s filtration system. The good news is that most of them can be fixed quickly, easily, and inexpensively.

1. Faulty Pressure Gauge

First, make sure your pool filter pressure gauge is correct. If there is no good reason why you are getting a high-pressure reading, your gauge may be the problem.

Cause of the Issue

Pressure gauges can and will wear out like all parts of a swimming pool’s filtration system. If your pressure gauge is older or is cracked or damaged, consider replacing it.

How to Fix It

If your pressure gauge is broken, your best bet is to replace it. Pressure gauges are inexpensive and will save you from spending time and money trying to fix a nonexistent pressure problem in your swimming pool’s filtration system.

2. Dirty Pool Filter

A high-pressure reading often indicates that it’s time to backwash your swimming pool filter. A dirty filter will impede the flow of water and result in pool water being in less than optimum condition.

Cause of the Issue

Pool filters don’t stay clean. Over time, the nooks and crannies of the filter get clogged with debris, chemicals, and oils from skin and sunscreens/lotions, and they can’t be hosed away. You need to clean your pool filter consistently and ensure it is the right size for your pool system.

How to Fix It

Best way to clean a dirty filter? Clean, clean, clean! Depending on the type of filter you have, you cleaning method will be slightly different.

For cartridge filters, I recommend hosing down thoroughly and using a cartridge cleaner. These can help remove the gunk left behind. That said, pool cartridge filters will eventually need to be replaced. Generally, they last 2 to 3 years.

For diatomaceous earth (DE) filtration systems, backwash them and open the filter to wash grids and remove any debris.

Sand filtration systems should be backwashed thoroughly. You’ll need to replace the sand in the filter every 3 to 5 years.

You may also want to check your filter’s media. In sand filtration systems, too much sand will slow water filtering through the tank, causing back pressure.

In diatomaceous earth systems, installing the wrong grid size or using too much DE powder can also create higher pressure readings (read my guide on how much DE powder to add to your filter to ensure you add the right amount).

3. Suction Air Leak

If your pool pump is showing high-pressure readings is could be caused by suction air leaks before or at the pump level.

Cause of the Issue

If there is an air leak in your pump system, more pressure has to be exerted to push dirty water through the filtration system. Over time, this will reduce the flow of clean water into the swimming pool. Bubbles in the pump basket are a tell-tale sign that a suction air leak is the culprit. Another sign is seeing bubbles coming back into the pool from the returns.

How to Fix it

Check for bubbles in the pump, using this to help you locate the leak. Inspect the skimmer basket, weir, unions, O-rings, and drain plugs to locate the source of the air leak. Then fill the pump up with water and prime it. This should fix the air leak in your pump system.

4. Clogged Breather Tube

The breather tube’s job is to release the air trapped at the top of the filter. Most pool filtration systems have a breather tube running from under the dome to the tank’s end. Some DE filters have built-in breather tubes that end at the discharge line.

Cause of the Issue

In filtration systems with breather tubes, air pressure at the top of the filter will build up if the tube becomes clogged.

How to Fix the Issue

If the pump’s breather tube is clogged, you’ll need to unclog it to get the pressure under control. Additionally, check the breather tube for damage or small cracks. If you detect damage, the breather tube will need to be replaced for pressure to return to normal levels.

5. Oversized Pool Pump

A pool pump that’s too large for your pool will result in a high-pressure reading for your filtration system.

Cause of the Issue

Your swimming pool pump should be able to push all the water through the filtration system and back into the pool within about 8 to 10 hours. More power than that, and you will have higher pressure readings. Having a higher horsepower than your pipes and filter can handle will mean that the pressure will build up after the pump.

How to Fix the Issue

If your existing pump has multiple speeds, try operating it at the lowest speed.

Replacing the impeller with a lower horsepower version might relieve the excess pressure. Make sure to check on whether the diffuser should also be replaced.

The other option would be to replace the whole pool pump with one that’s the correct size. Use my pool pump size calculator to help you find the right fit.

If you need to replace your swimming pool pump, check the turnover rate to ensure a perfect match of the new pump to the existing filtration system. Check out my research on the most efficient pool pumps for specific recommendations.

6. Underfilled Swimming Pool

You might get high-pressure readings if the water level in your swimming pool is too low.

Cause of the Issue

A low water level can allow air into your pool filtration system through the skimmer. Your pool’s water level should ideally be at the middle point of the skimmer.

How to Fix the Issue

Best way to fix this issue? Fill up your pool to the appropriate level!

7. Closed Diverter Valves

As its name implies, a diverter diverts the flow of water from one part of the swimming pool to another. If you have a diverter valve post-pump, it might have become closed to a section of return lines.

Cause of the Issue

If your diverter valve is closed and the pump is on, back pressure will build in your filtration system. A partially closed diverter valve will also create a bottleneck for water flow.

How to Fix the Issue

The good news is that this is an easy problem to fix! If your diverter valve is closed, just open up the return lines.

9. Undersized Return Jets

Another reason pressure may be rising in your filtration system could do with the sizing of your return jets.

Cause of the Issue

Having return jets that are not large enough for your pool’s system will impede the natural flow of water, creating back-pressure. If high pressure is a recurring problem, undersized return jets could be the cause.

How to Fix It

if your return jets are too small, the best way to fix them is to invest in larger return jets.

Get My Free Pool Care Checklist

Download my free, printable pool maintenance checklist to help you accomplish regular pool care tasks for any type of swimming pool.

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Feeling Under Pressure?

Life has a lot of high-pressure situations to throw at you. Don’t let your swimming pool’s filtration system be one of them.

Regularly monitoring your filtration system will extend its life and result in clean, clear swimming pool water. Armed with this information, If you see a rise in pressure, you’ll be able to track down what’s causing the pressure problem and make the fix.

Remember, your swimming pool is supposed to be an oasis of relaxation, not another source of high pressure in your life. I hope this handy guide to dealing with high pressure in your swimming pool filtration system will relieve the stress of keeping your swimming pool in optimal condition.

Have more questions about lowering the pressure in your pool pump? Let me know; I am happy to help!

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