Why won’t my pool filter spew out water? If there is no water flowing out of your pool filter, this is a sign there is not enough water flowing in.
A number of causes could be to blame for a low- or no-flow filter. Once you find the source of the problem, it’s critical to make repairs as soon as possible.
If you ignore a fussy filter, you may end up with leaks and/or damage to pumps that will cost a lot to fix down the road. Even if you are able to avoid costly repairs, you don’t want to risk contamination.
A smoothly-running filter is critical to pool hygiene, as some infectious organisms can survive in chlorine.
Disclosure: As an Amazon Associate, this site earns from qualifying purchases. Thank you!
1. Clogs & Obstructions
Obstructions can present themselves anywhere in your pool’s plumbing and filtration systems, but clogs in the pump basket, impeller pipe, skimmer basket, and/or valves are the most common reasons your filter will not work correctly.
To check for obstructions, first, turn your pump off. For pumps below water level, set the multiport valve on the filter to “closed.” And close the valves in front of the pump.
Now, check and empty both the skimmer basket (near the pool) and the pump basket (inside the pump itself).
2. Low Water Level
A low water level is another factor that can slow or stop the flow of water through your filter. Heavy pool use, long dry spells, and/or heat waves can cause water levels to drop.
In order to determine whether your pool’s water level is high enough, check the skimmer box. Ideally, the water level should be at least halfway up its opening.
3. Air Leaks
An air leak might be another reason your pool’s filter is malfunctioning. Even a tiny air leak can overstrain your pool’s pump and plumbing, leading to high energy bills or worse, permanent damage to your pump.
If you ignore an air leak long enough and your pump overworks itself for a while, it can eventually overheat and even melt.
Air leaks can originate in the pump itself, its lid’s O-ring, or other pipes and gaskets. If you discover multiple leaks and/or rust on any fixtures, it may be a sign your filter needs replacing.
Air Leaks in the Pump
Air leaks in the pump can let in more air than water, reducing filter pressure, and thus slowing or stopping the flow of water.
As you check for an air leak, keep in mind that regardless of its source, any air leak will originate somewhere before the pump impeller.
Typically, the most common air leak in the pump is where the male adapter meets the front of the pump. If you discover an air leak here, it’s likely because the thread sealant is too old.
Air Leaks in the Lid
If the sealant seems to be holding, the pump’s lid may be the source of the leak. Make sure it’s undamaged and on tight. Inspect the lid’s O-ring for faults and confirm the drain plugs near the pump are uncompromised.
Air Leaks in the Strainer, Pump Pipes, and Motor Assembly
Check the gaskets and O-rings on the motor assembly if the pump’s lid looks good. This includes the spinning impeller, the pump’s housing, and the strainer basket.
Check the gasket that seals the strainer lid. If it’s cracked, stretched out, or damaged in any other way, it needs replacing. Before you pop on the new one, clean out any gunk that accumulated in the groove it sits in and apply a new coat of lube.
If the O-rings and gaskets here look okay, it’s time to check the pipes that lead to the pump. Look for a part called the “union.”
It’s usually made of black or white plastic with two protrusions that look like big screws but are actually a single gasket and a screw-on adapter. Check the O-ring here for trouble.
Determining the Exact Location of an Air Leak
To repair an air leak, it’s crucial that you identify exactly where it is. A popular air leak detection method is to use shaving cream (foam, not gel).
Even though it sounds strange, many pool professionals swear by it, and it’s much cheaper and more accessible than higher-tech methods like ultrasound.
To use the shaving cream method, spread an even layer over any possible leak locations on the pump and the plumbing. Observe the shaving cream for spots where the white fluff dimples.
This is a sign air is getting sucked into the system; now you know exactly which part needs to be replaced.
4. A Pump That Needs Priming
Another answer to “why won’t my pool filter spew out water?” is to do with your pump. You might need to prime your pump. In other words, make sure it’s full of water.
To determine whether or not your pump is primed, look through its clear lid. If you don’t see any water, turn off the power and follow these steps:
- Unscrew the pump lid and put the O-ring somewhere safe. You’ll need to put it back on.
- If there are debris in the pump basket, empty it.
- Fill a bucket with water and pour it into the pump.
- When the water level reaches the top, close the lid with the O-ring and turn the pump back on.
These steps should usually work to get your pump going again, but if it doesn’t start in 15 seconds, follow these steps:
- Disconnect the suction cleaner, remove the vacuum plate, and empty the skimmer basket then try priming again.
- If this doesn’t work, turn the pump off again, set the multiport valve handle to “recirculate” and then try priming again.
If you’re still having trouble with your pump, give your pool a “shock dose” of chlorine and contact a pool professional.
5. Electrical Problems
If your filter won’t start at all, the problem is likely electrical or something’s wrong with the motor.
If this is the problem, it may be due to an overloaded circuit, loose connections, or a jammed motor (or trying to run the filter with a cheap extension cord).
Your motor may have shut down because it got too hot and overloaded the voltage. If you suspect this is the issue, remove anything blocking the fan that might be inhibiting its “breathing space.”
Compromised connections might be another reason your filter won’t start. Check all lines for broken or loose cords and replace any that aren’t in good repair.
If your motor is clogged, this could be the reason it won’t start. Check it carefully for leaves, bits of wood, and/or other debris, and remove any blockage.
Frequently Asked Questions
Still curious? Here are a few answers to the most commonly asked questions.
Why won’t my pool filter spew out water?
Pool filter flow problems stem from a number of sources. Among the most common causes of filter malfunctions are clogs, low water levels, air leaks, a pump in need of priming, and electrical problems due to an overloaded circuit, loose connections, or a jammed motor.
How do I unclog my pool filter?
Though clogs can happen anywhere in a pool’s plumbing and filtration system, obstructions in the pump basket, impeller pipe, skimmer basket, and/or valves are the most common.
To unclog any of these parts, first turn your pump off, then remove any debris causing the problem.
How do I prime my pool pump?
To prime your pump, first turn off the power, then unscrew the pump lid and remove any debris you find in the basket. Now, fill the pump to the top with water.
Why is my pool filter not pushing out water?
The reason your pool filter is not pushing out water may be due to a dirty filter. To resolve this issue, you should clean your filter by backwashing and rinsing your media filter. This will help to clear any blockages and allow the water to flow more easily. If cleaning the filter does not solve the problem, you can try turning off the pump and setting the filter to recirculate. If the water flow returns to normal in this mode, you can attempt backwashing again. However, if the issue persists, it may be necessary to replace the filter media as it could be due for a change.
How long does it take to prime a pool pump?
The time required to prime a pool pump is at least two minutes, during which water should be allowed to flow into the pump housing. This duration allows for water to seep into the pipes connecting the skimmer to the pump, ensuring sufficient water is available to create suction in the pump.
Why is my pool pump running but no water coming out?
Your pool pump is running but no water is coming out because the skimmer and/or pump baskets may be filled with leaves or debris, causing a restriction in water flow. To resolve this issue, check and empty both the skimmer basket located by the pool and the pump basket inside the pump. This will help reduce restrictions and allow water to flow freely.
Should water be running through pool pump?
Water should always be running through the pool pump because it is crucial for the pump to have a constant flow of water to ensure proper cooling during its normal operation.
How do I know if my pool filter is clogged?
The pool filter may be clogged if the pool water appears cloudy and dirty, even if the water filter is running. Additionally, if it takes a significantly longer time for the water to become clear after introducing dirt into the pool, it could indicate a problem with the filter.
What happens if pool filter clogs?
The potential outcome when a pool filter clogs is that it may result in the malfunction of the filter media, causing the release of all trapped particles. It becomes necessary to either clean or replace the filter, but this maintenance operation requires shutting down production temporarily.
Do pool pumps get clogged?
Pool pumps can become clogged due to small debris that can pass through the pump basket and obstruct the impeller, despite the presence of the basket in front of the impeller to prevent debris from entering the volute or causing impeller clogs.