Why Does Your Pool Pump Keep Losing Pressure (& How To Fix)

There’s no better way to beat the intense summer heat than by jumping into your backyard swimming pool with your closest friends and family. But what happens once the pool pump itself starts losing pressure or the pressure fluctuates wildly? Regardless of whether the problem is with the suction line, filter, or air pump, it’s important to fix it as soon as possible.

Your pool pump might be losing pressure due to a clogged filter basket or a suction leak. Try cleaning out any debris stuck in the pump basket, inspect the system manually for water leaks along the plumbing. Next, consider asking a pool professional to take a look before replacing the pump.

Low pump pressure usually indicates a problem with the “suction side” of your pool pump, which will affect the way the pump draws in water from your pool. Let’s look at why a pool pump loses pressure, what you can do to fix it, what PSI your pool filter should ideally be at, and whether you should replace your entire pool pump instead of trying to solve the problem.

What Would Cause a Pool Pump to Lose Pressure? 

Swimming Pool Filter

There are several reasons why a pool pump might lose pressure. To narrow down your options, it’s best to check one pump component at a time and then accurately identify the issue.

Problem elimination is easy, time-saving, and it can help ensure that you’re on the right track before hiring a professional pool technician for help.

Low Water Level

A low water level in your pool can result in your pump losing pressure. Make sure your water’s pool level is always above the skimmer basket, so the pump doesn’t suck in any air into its system.

If you notice bubbles coming from the jets into the pool, that’s a sure sign the pump is sucking in air, either from low levels emptying the filter basket or a leak somewhere on the suction side.

Blocked or Congested Skimmer Basket 

If the skimmer basket is congested or blocked with debris, the pipe connecting the skimmer to the pump will effectively be shut off. Generally, this will decrease the flow of water to the pool pump. 

Since the pump will suck in less water, it will push less water out as well, causing it to lose pressure. However, the problem can be easily fixed by cleaning the skimmer basket.

Clogged Impeller

The impeller is a pump component that resembles a fan and sucks water into the pump system. Sometimes, however, the movement of the impeller is obstructed by debris and rocks, causing your pump to lose pressure.

The filter basket is designed to prevent anything crashing into the impeller, but obviously if you pull the basket and it’s busted it means you probably have debris in your impeller housing and plumbing as well. This is pretty rare though, as the baskets are designed to be sturdy enough to prevent this.

Damaged Impeller

An impeller typically lasts as long or even longer than the pump itself. However, it can wear out over time or get damaged with regular use. 

If the pump impeller fails to work efficiently, it can result in low pressure. Since this component plays a big role in maintaining the right pump pressure, make sure you check it regularly to prevent the pressure levels from dropping. 

Suction Leak

A suction leak can cause several problems. If the leak’s large enough, the pump will suck too much air into its system, causing it to lose its prime. 

Conversely, if the leak’s smaller, the pump will suck in air, resulting in an air pocket over the filter tank. After a while, the air pressure at the top of the filter tank will release enough back pressure to decrease the flow and pressure of the water significantly.

Once you turn off the pump, this back pressure can also cause the water left in the suction pipe to flow back, resulting in a large column of water surging up through the skimmer.   

Blocked Pipes or a Too-Small Pipe Diameter

Anything that obstructs the flow of water on the pump’s suction side can result in lower water pressure. This includes a blockage in the pipes connecting the skimmer to the pump and pipes that are just too small in diameter to begin with.

Faulty Pressure Gauge

If all pool components are working well and you’ve eliminated all the above causes for a water pressure drop, then there might just be something wrong with your pressure gauge.

A faulty pressure gauge can prevent your pool pump from achieving the right water pressure. The needle might not fluctuate with the changing pressure levels, or it might just drop down to zero even if the pool pump is running. 

Pump Placed Too Far From the Swimming Pool 

Replacing your pool pump with a smaller model or moving the pool equipment around can result in a drop in pressure. The additional distance from the swimming pool might mean that the pump is too small for the job and unable to generate the pressure required. 

Underground Pipe Leakage

Seismic movements or tree roots can break and damage underground pipes. The leak is usually located on the suction side of the pool pump, which is between the pump and the skimmer box. 

Unfortunately, there’s no easy fix for this problem. You’ll have to dig up the pipes and replace them with new ones to ensure there’s no leakage again. 

Because the fix is so drastic, you want to be super sure this is the problem before you start digging. so how can you tell? Watch your pool water level over a few days. If you are losing a lot of water (several inches of vertical drop across a week, for instance) and you can’t find the leak where you’re losing that water, it means the leak is in that underground piping you can’t inspect. Grab the shovel!

How Do You Fix a Low-Pressure Pool Pump? 

Having a pump that keeps losing pressure can be frustrating, but it’s not a serious emergency. Even so, it’s better to fix the issue sooner than later. Here are a few ways you can repair a low-pressure pool pump: 

Unclog the Skimmer and Strainer Baskets

Emptying the strainer basket regularly can help ensure consistent water pressure and flow. The process also allows you to check the condition of the skimmer and the basket and replace them if necessary.

Here’s what you need to do: 

  1. Remove the cover of the skimmer.
  2. Reach in and lift out the basket.
  3. Discard whatever’s in the basket.
  4. Use a hose to spray the basket before replacing it.
  5. Place the basket back in the skimmer.
  6. Replace the cover. 

Unclog the Impeller

  1. Switch off the pump and the circuit breaker.
  2. Open the pool pump lid and remove the strainer basket.
  3. Use a screwdriver or your hands to pull out any debris stuck in the impeller.
  4. Rotate the impeller manually to ensure free, unobstructed movement.
  5. Replace the strainer basket and seal the lid. 

Unclog the Filter 

  1. Wash the cartridge filter before periodically soaking it overnight in a TSP solution (on Amazon) to clean out the gunk and grease stuck in the folds.
  2. Soak the filter cartridge in a weak muriatic acid solution (10:1) to remove the minerals from the folds. Make sure you do this step after soaking the cartridge in the TSP solution or the gunk will settle in the folds.  

If you have a sand filter, backwash it as required and change the sand after every five to seven years. In between changes, if the sand collects on top, remove one or two inches of sand from the top of the filter and replace it with new sand.  

Check the Pump Lid 

An issue here will be pretty easy to spot. It will look like water spraying out the top of the pump!

  1. Ensure the pump lid is firmly screwed on and sealed as it should be.
  2. Check the lid for cracks.
  3. Make sure the pump housing and the threads on the pump lid are undamaged.
  4. Replace the pump lid seal if it’s deformed or cracked.
  5. Replace the lid if it’s cracked or if threads are damaged in any way. 

Unclog Pool Pipes

  1. Lift out the skimmer basket and remove any debris stuck in the pipe.
  2. If you think there’s debris in the pool, but can’t reach it, try using a drain jet to remove it. You’ll need to attach the tool to a garden hose and insert it into the pipe.
  3. Push a thin, stiff wire down the suction or skimmer ports to push out any debris that’s clogging the entrance. 

If you’re unable to get rid of all the debris clogging the pool pipes, hire a pool professional to check and clean your pool pipes. 

Replace the Filter Pressure Gauge

  1. Switch off the pool pump and the circuit breaker. Cutting the power to the pump system will help prevent electric shock and ensure you don’t damage a more costly piece of pool equipment.
  2. Release the pressure by opening the air relief valve. This will help avoid injury during dismantling and will make it easier to disassemble pieces.
  3. Use a wrench to turn the pressure gauge in a counterclockwise direction and loosen it.
  4. Remove the faulty or old pressure gauge.
  5. Thoroughly clean the area.
  6. Wrap three to four layers of plumbers tape (on Amazon) around the threading of the new gauge and carefully place and secure it into the fitting.
  7. Use your hands to tighten the filter pressure gauge into the fitting. It’s better to tighten the gauge with a wrench as well until it’s secure.
  8. Switch on the pool pump and turn the air pressure valve.

What PSI Should a Pool Filter Be At? 

The ideal pressure reading for a pool filter depends on several factors. The size of the pool pump, the condition of the pool water, and the size of the pool itself have a direct impact on the pressure readings. 

Generally, a pressure reading somewhere between 10 and 25 psi is considered normal. Once you’ve installed a new pool filtration system, turn it on and take a baseline pressure reading.

Make sure you take a new reading whenever you change the pool filter. This will give you a better idea of the pressure reading you should aim for in your pool.

Check the pool pump’s pressure at least once every week. It’s also advisable to record the readings, so you can easily analyze trends and correct the water pressure as soon as you see any fluctuations.

What to Do if the Water Pressure Is Too High 

Fixing pool water filter

If your filter pressure consistently reads 10 psi or higher than the baseline, then the water pressure in your pool is too high. This simply means that your pool filter is clogged or dirty, and just needs a bit of attention. 

Depending on your filter, you might be able to clean out all the debris and restore optimal pressure readings. 

Most cartridge filters usually last around three to five years. However, if you find yourself continuously cleaning the filter or if you see high-pressure readings after every two to three months, then it’s best to get a new filter. 

What to Do if the Water Pressure Is Too Low 

If your gauge consistently shows a low-pressure reading, it means that the water flowing into your filter is too slow. This can be because of a leak or clog in the drains, baskets, or skimmers slowing down the water that reaches the filter.

If you see a pressure reading that’s five psi or lower than the baseline, check the entire filtration system and clean out any debris that’s creating a blockage. Also, replace or repair any faulty components. 

Clean out the baskets, drains, and skimmers, and then check the pressure reading again. If the low-pressure problem still persists, you might have a leak in the filtration system. 

If you can find and repair the leak yourself, you can have your pool pump up and running with minimal expense and effort. However, if you don’t have the required expertise, it’s best to hire a professional pool technician or just replace the pump entirely. 

Should I Replace the Pool Pump?

For the most part, your pool pump problems should fade away once you try all the solutions listed above. However, if you’re unable to locate an air leak and all components seem to be working fine, then you might have a faulty pool pump. 

Along with a drop in pressure, there are several other signs that indicate the need for a pump replacement. Most faulty pool pumps make strange noises, have a motor that shuts off mid-run, and produce low water flow rates. If you notice any of these signs, then it might be time to get a new pool pump. 

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