How do I test a sump pump?

Pour a bucket of water into the pit until the float rises: the pump should start promptly, empty the pit, and stop without chattering. Quarterly, and before the wet season, is the schedule.

How long do sump pumps last?

Roughly 7 to 10 years for a quality submersible in normal duty, longer for pedestals, shorter for pumps that cycle constantly. A pump past that age in a wet basement deserves proactive replacement or a backup.

Why does my sump pump run when it is not raining?

High groundwater, a footing drain system delivering water year-round, an underground spring, or, worth ruling out, a water line leak or discharged softener feeding the pit. Constant running in dry weather has a cause worth naming.

Do I need a battery backup sump pump?

If the basement is finished, or storms that flood your pit also knock out your power, yes. The primary pump's most likely moment of failure is exactly when the backup earns its price.

Sump Pumps: Types, Testing, and Maintenance

Page last reviewed: August 2026 · Reviewed by Harold R. Bennett, retired home inspector

A sump pump is the appliance whose entire career is one bad night, and sump pump maintenance is about making sure it shows up for it. The machine itself is simple, a float switch and an impeller in a pit, and its failure modes are famous enough to be a checklist. This reference covers the types, the quarterly test, and the backup question that finished basements should not skip.

The system in brief

Groundwater around the foundation collects, by design, in the sump pit, delivered there by footing drains or simple gravity through the grading and drainage story outside. When the pit fills, a float switch starts the pump, water leaves through a discharge pipe, past a check valve, to daylight or a storm system well away from the foundation, and the float shuts things down. Every component in that sentence has a signature failure, which is what the maintenance list is for.

Pedestal versus submersible

Submersible pumps sit down in the pit, motor sealed underwater: quieter, more powerful, out of the way under a proper pit lid, and the modern default, at a 7-to-10-year working life in normal duty. Pedestal pumps stand their motor on a column above the pit with only the intake below: cheaper, longer-lived (the motor stays dry), easy to service, and noisier, with less capacity, the fit for shallow pits and light duty. Capacity is rated in gallons per hour at a lift height; matching a replacement means matching or beating the old pump’s rating at your actual lift, and chronic-water houses buy the size up.

The quarterly test and the annual service

The test, five minutes: pour a bucket or two into the pit until the float rises. The pump should start without hesitation, evacuate the pit briskly, and stop cleanly. Listen for grinding (debris or bearings), chattering restarts (check valve or a waterlogged float), and note sluggish discharge (blocked line or worn impeller). A pump that fails the bucket test in April fails the storm in May.

The annual service, twenty minutes: unplug, lift the pump, and clear the intake screen of the sediment and gravel that pits accumulate; confirm the float travels freely through its whole arc, untangled from cords and pit walls (a hung float is the leading cause of both non-starts and burnout-by-running-dry); verify the check valve holds (water rushing back into the pit at shutoff means it does not, and the pump re-pumps the same water all night); and walk the discharge outside, confirming it exits freely, well away from the foundation, and, in cold climates, that the line cannot freeze shut, using an air-gap fitting or freeze-relief port so an iced outlet cannot deadhead the pump. Pit lids earn their place too, keeping debris out and, with a sealed lid, radon and humidity down.

Reading a pump’s complaints

Constant cycling points at a check valve failing, a float set too tight, or a pit too small for the inflow. Running nonstop in dry weather deserves a cause: high water table, a spring, or, worth the check, a hidden supply leak or a softener discharging into the pit. Rust flakes and oil sheen in the pit foretell motor age. And a basement that smells like a wet basement despite a working pump is telling a broader moisture story the pump alone cannot end.

The backup question

The primary pump’s most probable failure scenario is the storm: maximum inflow, and the same weather taking the power out. The answers, in ascending resilience: a battery-backup pump piggybacked in the pit, sized for hours of duty and tested on the same quarterly bucket; a water-powered backup (municipal pressure driving an eductor, no battery to age, at a water-use cost) where pressure and code allow; and a generator strategy for the whole house. Finished basements, and any basement that has flooded once, justify the backup arithmetic instantly, and an alarm, a simple high-water sensor or a smart leak detector, buys the phone call that turns a failure into an errand instead of a claim.

The bottom line

Bucket-test quarterly, clean the intake and exercise the float yearly, keep the check valve honest and the discharge unfrozen, and put a backup under any basement you would mind losing. The pump’s whole job happens on the worst night of the year, and everything in this list exists so that night is boring.