Why Is My Swimming Pool Pump Losing Pressure? 6 Explanations

If your pool pump is losing pressure, it won’t be able to circulate and clean the water. Your pool pump is the most important and influential part of the equipment pad. Without it, none of the filters, heaters, salt systems, vacuums, and other equipment will work. Fixing a low-pressure pump is much easier than it sounds, but the diagnosis is crucial.

Your swimming pool pump is losing pressure because the filter is clogged, there’s a leak around the O-rings, one of the pipes is cracked, or the skimmer basket is full of debris. Empty the baskets, then clean the filter to increase the pressure. If it’s still low, you should check for a leak.

Throughout this page, we’ll discuss six common reasons your pool pump is losing pressure, how you can fix them, and several preventative suggestions. We’ll also show you what your filter’s PSI should be, how to keep it from getting clogged, and more!

What Causes a Pool Pump to Lose Pressure?

If your pump is losing pressure, you might be worried or frustrated. When the pressure drops, the water can’t circulate as quickly as it should. This process can lead to a dirty pool that’s filled with algae, but it also means there might be a clog or leak. Built-up pressure can also cause damage to the pump, heater, filter, and salt system.

Here are the six most common explanations for what causes a pump to lose pressure:

1. The filter might be clogged by algae, leaves, and other debris. Pelican Bay Pools explains almost every drop in pressure is caused by an obstruction. This could be hair wrapped around the pump’s impeller, a cartridge filter overloaded with debris, and so on.
2. If the O-rings are cracked or dry, they’ll leak water and the pressure will drop. You should always have Pool Gasket Lubricant in your equipment area because O-rings should be lubed at all times. O-rings are found wherever two parts are joined, such as the pump lid, filter tank, unions, and skimmer.
3. A crack in a pipe, hose, or union can leak water and invite air bubbles into the system. If the pump pressure is dropping and you’ve checked the two previous issues, look for water drops around each connection. Filters and pumps should be airtight, so there shouldn’t be water spilled anywhere in the area.
4. A filled skimmer basket will cause less water to flow through the pump and filter. This common cause prevents water from pulling quickly enough. All you have to do is remove the leaves, but we’ll discuss more solutions in the following section.
5. If there are leaves in the pump’s basket, the same issue as above will happen. The pump has a basket under the lid that holds leaves that managed to make their way through the skimmer. Always turn off the pool pump before removing the lid.
6. The filter gauge might be broken, which requires a replacement. Last but not least, a broken gauge will either not move at all or will show false readings. If you’ve installed a brand-new gauge that isn’t reading pressure, you might’ve placed Teflon tape under the gauge while wrapping the threads. Simply remove the gauge, replace the Teflon tape, and check it again.

Read on for solutions to all of these low-pressure swimming pool pump causes.

How Do You Fix a Low Pressure Pool Pump?

To fix a low-pressure pool pump, remove the clogs, add lubricant to every O-ring, and clean the filter. Sand filters don’t have cartridges, so they have to be back washed.

Before trying any of these solutions, I highly recommend reviewing my guide to know if your pool pump is clogged. Once you’re able to diagnose the issue from the six possible causes mentioned above, it’s time to fix everything. Let’s get into it below!

• Remove debris from the pump basket, skimmer basket, and pool. Debris is the primary reason pool pumps get clogged, filters get dirty, and the pump’s pressure rises. Turn off the pump, remove the debris from the skimmer and pump basket, then head to the next suggestion.
• Clean the filter. A packed or dirty filter will slow the water pressure, much like trapped debris in the baskets. Sand and diatomaceous earth (DE) filters have to be back washed, whereas cartridge filters have to be sprayed to remove the debris. If you have a DE filter, you’ll occasionally have to spray the fins and add more DE.
• Lubricate or replace every O-ring throughout the equipment pad. Without lubricant, your O-rings will leak water. As discussed throughout this post, leaky water lowers your pump’s pressure. Gently bend the O-rings to look for small cracks or signs of wear and tear. Orange Seal estimates most pool O-rings last up to 7 years.
• Consider performing a dye test (this process usually requires a professional swimming pool company). Dye tests pour colored drops through the swimming pool. Wherever there’s a crack, you’ll see dye come through. This is an excellent method for those with plaster pools.
• According to Bob Vila, leaky pipes remove water and drop the pressure. Check every pipe or hose on the equipment pad. If you have an in-ground pool, there are more than likely PVC pipes. On the other hand, above-ground pools typically use plastic corrugated hoses.

What PSI Should a Swimming Pool Filter Be At?

A swimming pool filter should be at 10 to 20 PSI. Check the filter’s manufacturer’s guidelines to know the exact recommendations. If the PSI is too low, it needs to be checked for leaks. If the PSI is too high, there’s likely a dirty filter.

Oddly enough, a clog will affect the filter and pump differently. If there’s too much debris or a dirty filter, the pump’s pressure will drop but the filter’s PSI gauge will increase. The increased PSI is caused by the water trying to push through the debris, but since it doesn’t get enough flow, you’ll notice less pressure coming from the pool pump.

Can a Pool Pump Get Clogged?

A pool pump can get clogged by leaves, sticks, algae, debris, pool toys, and more. Turn off the pump and check the skimmer basket and pump basket. Remove the pump’s basket and reach your hand back to the impeller to remove hair and other debris tangled around it. A restricted impeller can cause the pump to overheat, grind, and make odd noises. It can also lower the pool water pressure.

Fortunately, keeping the pool clean and checking the baskets are the primary (and often only) steps you’ll need to take to prevent and treat pool pump clogs.

How Do You Unclog a Pool Pump?

To unclog a pool pump, follow these steps:

1. Turn off the pump and check the breaker to ensure it doesn’t have power going to it.
2. Empty both of the baskets (pump and skimmer).
3. Use a screwdriver to unbolt the pump from the pad (if it’s bolted), then remove the remove the front part of the pump from the back part (known as the pump housing and motor, respectively).
4. Remove the impeller, then replace the pump seal.
5. Unclog anything on, behind, and around the impeller.
6. Attach the front and back (housing and motor) of the pool pump.
7. Bolt it to the pad and replace the pump’s lid.
8. Turn on the break and power the pump on.

Some pools are variable speed models, which means they can work on multiple speed settings. Also known as VSP’s, these pumps are very energy-efficient and can drop to a lower pressure whenever needed. If you have a variable speed or two-speed pump, ensure it’s not on the lower setting if you’re worried about the reduced pressure.

In Conclusion

If your pool pump is losing pressure, you shouldn’t ignore it. Lost pressure can be caused by a cracked in one of the pipes or fittings, which can worsen and cause much worse problems for your swimming pool. Even if it’s something as simple as a cracked O-ring, fixing a pool pump that’s dropping in pressure is recommended to keep filtering the water.