Test your sump pump at least every three months by pouring water into the pit and watching it start, empty the pit and shut off. Look at the pit and the outdoor discharge monthly, check any battery backup monthly, and give the whole system a closer look before your wet season starts. Zoeller's manuals set that three-month minimum.
Sump pump maintenance checklist#
| How often |
What to do |
| Monthly |
Look into the pit for debris, check the pump is plugged in and the outlet has power, check the battery backup and its connections |
| Every 3 months |
Bucket test the primary pump and any backup pump |
| Before the wet season |
Full test, clear the pit, walk the discharge line outside, test the high-water alarm |
| After a power cut or big storm |
Check the pump restarted and the GFCI outlet hasn't tripped |
| Yearly |
Clear debris from the pit and around the pump intake, if your manual allows |
The three-month test comes straight from Zoeller's installation instructions for its Model 63 and 95 pumps, which tell owners to inspect and test the system for proper operation at least every three months. If your pump's manual sets a tighter schedule, follow that one.
Safety first#
A sump pit is water and electricity a few inches apart. Zoeller's manual says to shut off the breaker and unplug the pump before handling it, and not to stand in water while you do. If the basement is flooded, don't wade in to reach the pump. Call your electric company or a licensed electrician to cut the power first.
Don't run a sump pump on an extension cord. Zoeller's instructions rule it out and call for a properly grounded outlet.
How to test a sump pump#
- Check the pump is plugged in and the outlet has power. If it's on a GFCI outlet, make sure it hasn't tripped.
- Fill a 5-gallon bucket with water.
- Pour it slowly into the pit until the float rises. On a pump with a separate float switch, you can see it lift.
- The pump should switch on, pull the water level down and switch off cleanly once the float drops.
- Listen. A steady hum while it pumps is normal. Grinding, rattling or a pump that hums without moving water is not.
- If you can, have someone watch the outdoor discharge point to see water actually coming out.
If the pump doesn't start, stop pouring. Don't keep filling the pit. Check the power, check the float isn't caught on the side of the pit or the power cord, and if it still won't run, call a plumber or the pump's service center.
Testing a battery backup pump#
A backup pump only matters if the battery is ready, and batteries quietly die. Zoeller's Aquanot Fit backup system manual puts checking the battery and its connections at least once a month on the owner, alongside the same three-month system test.
- Look at the controller's status lights and read what they mean in the manual.
- Check the terminals are tight and free of corrosion. Wet-cell batteries contain acid, so wear gloves.
- Test the backup by following its manual. On some systems that means lifting the backup float, on others pressing a test button.
Some newer controllers run self-tests and send alerts to your phone. They're useful, but they don't replace the quarterly bucket test. You still want to see water leave the pit.
Zoeller recommends a 12-volt marine deep-cycle or AGM battery for its backups, not a car battery or a gel battery, and gives its own batteries a three-year warranty. Treat that as a hint about when to start thinking about a replacement.
Signs your sump pump needs attention#
The Zoeller troubleshooting chart lines up common symptoms with their usual causes:
- Runs constantly or won't shut off: debris under the float, or the float stuck against the pit wall
- Turns on and off too often: a stuck or missing check valve, a float that's tight on its rod, or a pit that's too small
- Runs but moves little or no water: a clogged intake screen, a blocked discharge pipe or check valve, or a clogged vent hole
- Won't start: no power, a tripped breaker or GFCI, or a float held down
Also watch for water coming back into the pit right after the pump shuts off, which points to the check valve. Odd smells, rust on the pump and a pit that fills far faster than it used to are all worth a professional look.
The parts people forget#
The check valve. It sits on the discharge pipe just above the pump and stops the water you just pumped from falling back in. If you hear water rushing back after each cycle, it's not closing.
The vent hole. Zoeller recommends a small hole in the discharge pipe between the pump and the check valve, below the pit cover, to let trapped air out, and says it should be cleaned periodically. You'll see a small spray from it when the pump runs. That's normal.
The outdoor discharge. Walk outside and look at where the water goes. It should be clear of leaves and soil, not frozen shut in winter, and draining away from the house, not pooling against the foundation to seep straight back into the pit. Clean gutters and downspouts that send roof water away from the walls take a lot of load off the pump.
The pit cover. Zoeller wants a cover on every installation to keep debris out. It also keeps kids, pets and dropped tools out.
When to call a professional#
Call a plumber or the manufacturer's service center if the pump fails a test, makes grinding noises, trips the breaker, or runs nonstop in dry weather. Zoeller's own manual says not to take the pump apart and to have repairs done by an authorized service station. Don't open a sealed pump or alter the wiring.
Fitting it into your year#
Set a ChoreLists.com reminder every three months for the bucket test, with a monthly one for the battery check if you have a backup. Put the before-the-wet-season check alongside your winter prep or spring list, whichever comes before your heavy rain, and keep the pump model and a service phone number in your home maintenance checklist.