Sump pump runs constantly?

A pump that runs nonstop during heavy rain or a high water table may be doing its job. If it runs when it's dry out, suspect a stuck float or a failed check valve letting water fall back into the pit.

Not sure which one it is? Snap your sump pump and we’ll narrow it down.

Is the pump silent instead, with water rising?

That's a pump that isn't running at all. Sump pump not running

Likely causes

Heavy rain or a high water table
Most commonEasy DIY
The pump runs often during or after a storm or snowmelt, and slows down as the ground dries. That can be normal. If it runs nonstop when it's dry out, look at the other causes.
Float stuck in the on position
CommonModerate DIY
The pump runs with little water in the pit, or doesn't shut off. The float is caught up on the cord, the pit wall or debris. Unplug the pump before reaching in to free it.
Part: $75–125 (float switch repair), $100–150 (replacement)
Failed check valve
CommonModerate DIY
The pump shuts off, then restarts soon after, and you may hear water falling back into the pit. The check valve on the discharge pipe is meant to stop pumped water flowing back.
Pump too small for the inflow
Less commonCall a pro
The pump runs without pause during rain and the pit still fills. It can't keep up with how much water is coming in, and a larger pump is the fix.
Part: $800–2,000 (submersible, installed), $400–600 (pedestal, installed)
Clogged or frozen discharge line
Less commonModerate DIY
The pump runs but water leaves slowly or not at all, so the pit stays full. Check where the discharge pipe exits outside for ice or a blockage.
Air-locked pump
Less commonCall a pro
The motor runs but no water moves. Air trapped in the pump keeps it from pumping.

Quick checks

If the basement is flooded, don't step into water that could touch outlets or cords. Turn the power off at the breaker only if you can reach the panel from a dry spot; otherwise call an electrician or the utility. Unplug the pump before reaching into the pit, don't run the pump from an extension cord, and wear gloves, because pit water can be dirty.

If the basement floor is wet, don't step into water that could touch outlets or cords. If you can reach the electrical panel from a dry spot, turn the power off at the breaker; if you can't, call an electrician or the utility.
Look at the pit: if the water is high and it's raining or the snow is melting, the pump may just be working hard.
Unplug the pump before reaching into the pit, and wear gloves, because pit water can be dirty.
Check that the float moves freely and isn't caught on the cord, the pit wall or debris.
Look at the discharge pipe outside for ice or a blockage.
Don't run the pump from an extension cord. If the pump won't start at all, see sump pump not running.

Sharpen the read

Diagnose your sump pump in seconds, for free

No account, no phone number. Fixology’s AI reads your photo and tells you what’s likely wrong, how worried to be, and whether it’s a DIY fix.

Snap one of these:

the pump and float in the pit
the discharge pipe and check valve
the outlet the pump plugs into
the pit water level

Add a note or more photos next. Nobody calls you.

When to call a pro

The pump runs nonstop when it's dry out and a free float doesn't fix it, it can't keep up in heavy rain, water is reaching the basement floor, or you suspect a failed check valve or an air lock. HomeAdvisor puts a sump pump repair at an average of $531 ($309–755). For a pump that stays silent, see sump pump not running. For upkeep, see the sump pump guide.

Typical cost: HomeAdvisor puts sump pump repair at an average of $531 ($309–755). A float switch repair is $75–125 and a replacement $100–150. A new pump installed runs $800–2,000 for a submersible and $400–600 for a pedestal. A pump lasts about 10 years with maintenance. HomeAdvisor gives no figure for a check valve.

Sources: HomeAdvisor: How much does sump pump repair cost? (updated June 17, 2026)

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