Sump pumps generally operate fairly quietly, so if you start hearing yours, it is time to figure out what is happening. The pump is there to keep your basement dry. Keeping it running to do that job can save costs and aggravation.
Here are some of the more common sump pump noises, what may be causing them, and what you can do to fix both the noise and the pump.
Submersible Sump Pump with Flex Hose and Flush 3/4″ Plywood Cover
5 Common Sump Pump Noises
One of the reasons sump pumps are quiet is that they are usually quite a ways from your living space. The good part of this arrangement is that you do not have to put up with noise from the pump or water moving. The bad part is that something can be going wrong for quite some time before you become aware of it.
If the pump is operating properly but you can still hear the noise please see our article How to Quiet a Sump Pump: The Only Guide You Need for more information.
1) Sump Pump Gurgling Noise
The gurgling or slurping noise you hear when your pump shuts off is water in the pipe running back down into the pump and pit. This should not do any damage to the pump. But long term it will shorten pump lifespan somewhat because it is continuously repumping water. You can solve this problem by installing a check valve in the water line close to the pump water outlet. Choose from 2 types of valve.
- Swing Check Valve. Swing valves are inexpensive and function well either vertically or horizontally to stop water returning to the sump. Unfortunately, you may be adding noise to your system using one of these valves. They can slam shut when water flow is suddenly shut off and water in the pipe tries to flow back into the pit. You can also get water hammer from the sudden stoppage of water flow which leaves it no place to go. The water will bang against pipe and valve for a bit–making the hammering noise until it calms down.
- Spring Check Valve. Spring valves are often called the silent valve because they eliminate valve gate banging and water hammer noise while still preventing back flows. They generally cost about $10.00 to $20.00 more than swing valves.
2) Sump Pump Humming Noise
Your sump pump is going to make a soft humming noise when it is working–like all electric motors. But if the humming is getting louder or the pump is not pumping water, you should investigate a few things.
- Vent Hole. Check for a clogged vent hole and clean it out if necessary.
- Check Valve. Check valve may be stuck closed–specially if it was installed backwards in the line.
- Pipes/Hoses. Your pipes might be plugged. But more likely they will freeze–at certain times of the year. You can generally get them thawed by using a space heater. If frozen pipes are a regular problem, give some thought to wrapping heat tape around the offending section.
- Impeller. A broken impeller will impair water pumping. It should be replaced as soon as you find it.
- Filter. Even a partially plugged filter will slow water flow and cause a humming sound. Make sure you clean the filter or change it if it is damaged.
3) Sump Pump Grinding Noise
A grinding noise coming from your sump pump is almost always a sign of a jammed or defective impeller. Grinding pumps need to be dealt with immediately to prevent more impeller damage. If caught early enough, just cleaning out the impeller and housing can make the pump run smoothly and quietly again. The longer it is left, the greater chance of damaging the impeller or burning out the motor.
Replacing an impeller is not a big job, but it is more involved than clearing a jam.
4) Sump Pump Banging Noise
Loose discharge pipes can cause banging noise. Every time the pump cuts in, the pipe will bang against surrounding framing, other pipes, or even the sides of the pit. Any of these situations require a fairly simple fix. Just add an extra strap or bracket to the pipe and attach it securely to your framing, or the other pipe it is banging against.
Adding a piece of foam or anti vibration pad between the pipes where they are touching, or may hit, another pipe or a framing member will also help quiet them down.
5) Sump Pump Clanging Noise
Clanging noise and banging noise are both caused by loose pipes. The difference is that a banging noise is usually a one-time occurrence–every time the pump starts or stops; clanging is generally continuous caused by vibration when the pump is running. Use vibration pads between your pipes and the framing you are securing them to.
Some sump pump piping is not attached to much of anything, but left to wave in the air with a bunch of 90 degree angles that will slow down water flow. It is a good idea to replace elbowed pipe with straight ABS piping, if possible. This helps eliminate some of the vibration.
A couple of other ways to reduce clanging noise are:
- Lid Soundproofing. If your pit has a lid, and most of the piping is inside the sump, install soundproofing weatherstrip between the lid and pit.
- Pipe Soundproofing. Soundproof the pipes with foam sleeves that are made to slip over individual pipes and reduce noise.
Note: A medium sized sump pump can move over 4000 gallons of water per hour. That works out to over a gallon per second being forced through a 1 1/2″ pipe. Making vibrations easier to understand.
A Few Other Sump Pump Noises
Besides the most common noises listed, sump pumps can make a few other noises for you to be curious about.
- Slurping Noise. Slurping noise is exactly what it sounds like–the pump trying to suck up the last bit of water in the sump. It is nice to clean out the pit every time the pump runs, but it is noisy and can help shorten the life of a sump pump. With a little help from the owners manual, you can adjust the automatic pump switch to turn off a little sooner and eliminate the noise.
- Rumbling or Squealing Noise. Rumbling and/or squealing noises are often caused by a pump bearing wearing out. Depending on the pump, you may be able to change the bearing. But you would still have an older pump with old impeller. I would probably just replace the pump.
When to Buy a New Sump Pump
Sump pumps usually last quite a long time. (Our submersible has been going strong for 15 years.) If you have tried everything to quiet the pump or make it pump faster, it is probably time. Prices for new sump pumps vary from well under $100.00 to well over $400.00 with sensors and alarms. If, and when necessary, I can replace ours with a close to identical unit for around $150.00.
Don’t wait too long to replace a failing pump. Having your basement flood because the pump dies on you can be depressing. Having a spare pump in case of emergencies is not a bad idea.
For more detailed information about new sump pumps please see our article The Best Quiet Sump Pump of 2023.
Cost Benefit Analysis
This is kind of a fancy name for a way to justify a new sump pump. Instead of trying to replace a bearing, or impeller on an old pump. But consider this. My pump cost $150.00. It has lasted 15 years so far. Meaning it cost me $10.00 per year, or less than $1.00 per month of use. I have no reason to expect less from a new pump.
If I repair the old one, I have the cost of parts and the time involved, which may not be worth much, but I could be doing something else instead of working on the sump pump. Even installing a new sump pump.
I suggest that you invest in a sump pump overflow sensor. They range in price from around $20.00 to $200.00–much less expensive than a flooded basement if your sump pump packs it in. Flooded basements are an expensive mess. Sump pumps are rarely on anyone’s list to check daily.
Our sump is in the laundry room, which is not visited daily. The picture below shows our sump pump lid and our overflow protection–a 3′ long pipe cut into the concrete to allow water to flow into the floor drain if the pump quits.
Covered Sump Pit With Emergency Overflow.
When to Call a Plumber
A sump pump is usually fairly easy to service, and replace. Whether it is a submersible pump or a pedestal pump. But if you are not a DIY person, call a plumber to take care of your problems. He/she should be able to diagnose and fix the problem quickly and efficiently. Expect a labor warranty and a product warranty when the job is done.
Make sure you get a quote before the work starts to save you from a surprise later on.