Sump pump maintenance: schedule, lifespan and costs
Updated
Overview
A sump pump sits in a pit at the lowest point of the basement or crawl space and pumps out the groundwater that collects there before it reaches the floor. It runs only when the water rises, which may be rarely for months and then every few minutes in a storm. That's what makes it easy to forget and dangerous to neglect: it only has to fail once, on the wrong night, to flood the basement. Its maintenance is a test every few months and a leak sensor beside it that tells you if the test is ever failed for real.
Lifespan
A sump pump lasts 7 to 10 years. A pump that runs often, in a wet area with a high water table, wears its motor and its impeller and lands at the short end. A pump that sits idle for long stretches can seize or rust at its switch, and lands there too. The float switch, which turns the pump on, is the part that fails most, and a stuck float is the most common reason a working pump doesn't run.
What extends the life is a clean pit, so nothing jams the float or the impeller, a check valve that keeps water from running back into the pit after each cycle, and regular tests that catch a sticking float before a storm does. The signs a pump is near the end: grinding or rattling while it runs, a pump that runs longer each cycle to empty the same pit, a motor that's tripped its breaker, and an age past 7 years with any of those.
Maintenance schedule
The pump's test, and the sensor that backs it up.
| Task | How often |
|---|---|
| Test the sump pump | every 3 to 6 months, and before the rainy season |
| Test the water leak sensors | every 3 to 6 months |
Replacement cost
Replacing a sump pump costs $400 to $1,200 installed. The low end is a basic submersible pump dropped into the existing pit, and the high end adds a battery backup pump beside it, a new check valve and discharge line, or a larger pump for a pit that fills fast. A battery backup is worth the extra for any basement that floods when the power is out, which is when storms fill the pit.
The repair-or-replace rule: a sump pump is cheap enough that most faults are replacements. A stuck float that frees up, a clogged intake, or a failed check valve is a fix. A motor that hums and won't turn, a pump that's lost its pumping power, or one past the middle of its lifespan with any fault is a new pump, and swapping one on a dry day costs the same as in a storm.
Common problems
- The pump doesn't start when the pit fills: a stuck float, a tripped breaker, or a dead motor. Test the sump pump with a bucket of water to find out which.
- The pump runs without stopping: a float stuck up, a check valve letting water run back into the pit, or a pump that can't keep up. Unplug it and look at the float and the valve.
- Water on the basement floor with no warning: the pump failed quietly. Test the water leak sensors so a sensor beside the pit catches the next one.
- Grinding or rattling while it runs: debris in the impeller, or bearings on their way out. Unplug the pump and clear the pit.
- The pump runs but the pit doesn't empty: a blocked or frozen discharge line outside, or a failed impeller. Check where the line exits the house.
- The check valve bangs after each cycle: the valve is worn or installed without a quiet-close feature. It's a cheap part to replace.
FAQ
How long does a sump pump last?
About 7 to 10 years. A pump that runs often wears out sooner, and one that sits idle can seize. Regular tests catch both.
How much does it cost to replace a sump pump?
$400 to $1,200 installed, from a basic submersible pump to one with a battery backup and a new discharge line.
Do I need a battery backup sump pump?
If the basement floods when the power is out, yes. Storms that fill the pit also knock out the power, and a backup pump runs through it.
How often should a sump pump be tested?
Every 3 to 6 months, and before the rainy season. Pour a bucket of water into the pit and watch the pump start, empty it and stop.
Why does my sump pump keep running?
A float stuck in the up position, a check valve that lets water drain back into the pit, or more groundwater than the pump can move. Check the float and the valve first.