Low Pool Water Pressure, Identifying and Fixing

A pool water pressure drop could mean many things. Today, we’re going to go over what the possible causes can be and how to fix them. But before that, we’re going to look at how to identify the symptoms of low water pressure.

Low Water pressure symptoms

Here are some of the symptoms to look out for that may signify a low pool pressure problem.

  • Slow return jets - if you notice that your return jets are sluggish or have fallen down to a trickle, then this is a sure sign that you have low water pressure.
  • Visual cues - if you have a water feature that’s connected to your pool’s filtration system, then a slowdown of your water features (i.e. waterfalls) is sure fire way to identify that you have a low pool water pressure problem.
  • Sluggish pool cleaners - Now if your once active pool cleaners have trouble starting up or they look to be struggling or sluggish, then you have low pool water pressure.
  • Pressure alarms - if you have a salt water chlorinator, heater, or anything attached to your pool with a water flow or water pressure detector then an alarm stating that you have a low flow problem should be more than enough to tell you that you have a low pool water pressure problem.

Now that we know how to diagnose low water pressure, let’s now go and identify what’s been causing the problem and fix it shall we?

Pool Suction Side Problems

When we say suction side problems, this means that the problem is located BEFORE your pool pump. Here are the common suction side problems that can cause low water pressure problems.

Cause: Low Water Levels

A low water level can cause low pool water pressure by allowing air to be sucked in to your pump through your skimmer boxes. Air getting sucked into your pump will cause it to lose prime and cause low water pressure.

Low Water Level Solution

Raise your pool water to its proper levels, which is about halfway through your skimmer box openings.

Cause: Dirty or full skimmer or pool pump baskets

Pretty straightforward problem. If your skimmer basket or pool pump basket is full of debris, then it follows that water flow to your pump will be restricted, and in turn cause low water flow and low water pressure.

Pump and Skimmer Basket Solution

A straightforward problem calls for a straightforward solution. Simply clean out your skimmer and pool pump baskets and you should be good to go!

Cause: Clogged impellers

A clogged impeller is more common than many people might imagine, especially when skimmer and pump baskets are damaged. The dirtier the impeller, the lower the water pressure will be.

Solution to Clogged Impellers

Turn off the power first before fiddling with your pump! Cut off the power completely, especially if you have a timer system involved to avoid any accident! Once the power is off, open up your pump lid and take out the pump basket, you should have access to the impeller. Get some wires and make a small “hook” at the end and then bend the wire at around 6 inches or so, depending on your pump model and size just to make maneuvering much easier. You should now be able to “fish” out any large pieces (or clumps of) debris that have been clogging up your pool pump’s impeller.

Now, for heavier clogs, you may need to take out your impeller to clean it, to learn how to open up your pump, we have a comprehensive guide on how to open up your pump which you can see here. Note on the linked post, it's on how to install a mechanical seal, but the first steps involved is to take out your impeller so it's applicable when you're trying to clear an impeller clog.

Cause: Air Leaks

Air leaks, no matter how small, can cause huge problems, especially with pool water pressure. And the kicker is, unless you’re actively looking for it, suction side air leaks are almost impossible to detect with casual observation. Very tiny air leaks can manifest themselves as bubbles in the return jets or bubbling in your pump basket area. So if you see these things, then you should start to actively look for air leaks as soon as possible. Larger air leaks can manifest themselves as your pump losing prime more often, air building up inside of your filter, and sometimes even cause your skimmer lid to blow off once the pump is shut off!

Detecting Air Leaks

Our favorite method to use for detecting air leaks is to use a bucket of soapy water. With the pump running, smear bubbles over seams, connections, your pump lids, unions, joints, and fittings. Any air leak should be visible if you see the bubbles getting sucked in.

Solution to Air Leaks

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If you have an air leak on any part that uses an O-ring, simply replace the O-ring to give it a good seal. Now for air leaks on other fittings or joints, either do some minor plumbing work to replace the affected fittings or joints, or you can use some Aussie Gold Aqua Fix-it to give the joint a good fix/seal. This patch-up job should last for a few years so you can stave off doing any plumbing work for at least a few years or until you have a renovation planned.

Cause: Clogged intake lines

Clogged lines are usually caused by debris that manages to slip in through your skimmer baskets and get trapped somewhere in between the skimmer box and your pool pump.

Solution to Clogged Intake Lines

Now some people might suggest to get some wire or a plumber’s snake to manually fish out any debris causing the clog, but for us, that feels a little inconvenient. The main reason for this is that your intake lines are pretty lengthy and we don’t really know where the clog is. The clog could be just a few inches from the opening or it could be metres or down the line. The most convenient way (and effective in our book!) is to get a hose bladder or a drain king to blast the clog out.

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The first step is to take out your skimmer basket first as we’re going to be pushing the clogged debris back out to your skimmers. Once that’s done, get the drain king attachment as far into your pump intake as possible, better and easier if your pump is attached with a union as you can just detach your pump and stick the drain king into the intake pipe. Turn it on and watch the clogged debris get blasted back into your skimmer box! Once that’s done, simply scoop out all of the debris, clean everything and put everything back into place and your low pressure problem is solved! You may want to prime your pump again though if you don’t have a self-priming pump.

Pool Pressure Side Problems

If you’ve ruled out any problems on the suction side that may cause low water pressure problems for your pool, it’s now time to shift your attention to the pressure side or basically everything after your pool pump.

Cause: Filthy Cartridge Filter Media

The number one pool pressure side problem that can cause low water pressure is having dirty filter media. And not surprisingly, this is the easiest problem to fix! Hose down your cartridge filter elements or give it a good soak in some Zodiac filter cleaner.

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If this doesn’t resolve the filter your low water pressure problem, try and run your your pump WITHOUT the filter cartridge itself installed in the filter tank. If this solves the problem then it's a sure sign that you will need to change your filter cartridge.

Browse our collection of filter cartridges here or click here to learn how to correctly measure your cartridge filter. 

Cause: Gunked up Sand Filters

Now if you have a sand filter, a cause for low water pressure may be that the filter is in need of a good backwashing. We have a detailed backwashing guide that you can check out here.

If after backwashing your sand filter you still have low water pressure, you can do an even longer longer backwash (just double the time of your normal backwash) to see if that solves the low pressure problem, if it doesn't then we still have one step to try.

Get some zodiac filter cleaning solution, add it directly to your sand filter (don't forget to close off the valves) mix it if possible, allow to stand for 24 hours. After letting it stand for 24 hours give it a good backwashing. Now this should melt away any stubborn oil particles or gunk build up in your sand filter tank.

If this still doesn't fix the low pressure problem, then it may be time to change your sand filter media. See our detailed guide on how to change your sand filter media here.

Cause: Pressure Side Leaks

Small leaks on the pressure side don’t really affect the water pressure of your pool. If you have minor leaks around your filters then some plumbing work might be in order as it’s not advisable to patch it up with pool putty since the water pressure will make short work of anything covering up any leaks

Now, leaks that are substantial enough to cause a water pressure drops will usually lie undetected as these are usually located underground in between your filtration system and the return jets. If everything in your filtration system plumbing (pumps, filters, heaters, etc) looks to be in order then take a good look at the area where the pipes leading to your pool are located. Check the ground and feel the soil, if it’s constantly moist then that’s a possible sign of a sizeable underground leak. For leaks like these, it’s best to call a pool professional or a contractor to take a look as this will involve some excavating and some serious plumbing work.

Other Considerations

We’ve just shown you all of the possible causes of low pool water pressure. Now if everything seems to be in order and you still have low water pressure then you should think back to anything that you might have added recently or changed in your pool. Did you add a water feature? Did you change pool pumps? Sometimes the problem is caused by something that we added/removed from the pool so it’s important to think back to any changes that we might have done.

One thing that many people fail to consider is that over the years, they start to add pool features like heaters, salt water chlorinators, water features that their pumps can no longer handle the added load. If this is the case, then check out our selection of pool pumps here.

Do you have any questions about this topic or the featured products? No worries, we're here to help! Drop us a question down below and we'll get back to you ASAP.

Happy swimming :)

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Post author:

Tom Hintze

Head of eCommerce & Operations at Mr Pool Man,
Co-Founder at Water TechniX

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