Sump Pump Not Working: Seven Checks Before You Call
A sump pump sits quiet for months, then has to work hard on the one night it matters. When it does not start, water rises fast. A short checklist finds the cause more often than you would expect.
Call (720) 794-0054Start with the water level
Look into the pit. If water is near the top, move quickly and reduce the water coming into the house. Turn off washers and stop running showers while you check. If the pit is dry and the pump is silent, nothing may be wrong. A pump only runs when water lifts the float. Pour a bucket of water into the pit and watch whether the pump starts.
Seven checks, in order
- Power: is the pump plugged in, and has the GFCI outlet tripped?
- Breaker: has the circuit breaker flipped?
- Float: does the float move freely, or is it stuck on the pit wall or a cord?
- Intake: is the intake screen blocked with silt or gravel?
- Discharge: is the outlet pipe frozen, kinked or blocked outside?
- Check valve: does water flow back into the pit when the pump stops?
- Noise: does the motor hum but not pump, which can mean a jammed impeller?
Reading what you find
Symptoms and likely causes
| What you see | Likely cause | Typical next step |
|---|---|---|
| Nothing happens, no sound | No power or a failed switch | Reset the GFCI and breaker, then test |
| Pump hums, no pumping | Jammed impeller or a failed motor | Unplug, then call |
| Pump runs and does not drain | Frozen or blocked discharge, or a bad check valve | Check the outside outlet |
| Pump cycles on and off | Float problem or a failed check valve | Inspect the float and valve |
| Pump runs all the time | Stuck float, or water inflow is high | Check the float |
Pump not starting and water rising?
Unplug the pump, reduce water use and call. The dispatcher will plan a visit.
Why a sump pump quits in a Colorado winter
Discharge lines that run outside can freeze. The pump then pushes against ice and may overheat. If the outlet is frozen, thaw it safely and consider rerouting it. Pumps also fail from age. A pump that has run for years can lose power or burn out. A sump pump is among the first things to look at after a long dry spell, because the first heavy runoff can be the first test in months.
Why Brighton basements take on water
The Colorado Geological Survey describes expansive soils that swell when wet and shrink when dry. Clay-rich ground can send water along foundation walls and under slabs when snow melts or the irrigation season runs heavy. If you have a pit and a pump, the pump is the last defense. Direct downspouts away from the house and keep the grade sloping away from the foundation so the pump works less.
What you can safely do yourself
You can reset a GFCI, test the float and clear a screen. You can pour water into the pit and watch the pump run. Always unplug the pump before your hand goes into the pit. Avoid touching wiring while standing in water. If the floor is wet around the outlet, cut power at the breaker panel from a dry spot, or call.
When it is time to call
Call if the pump hums but does not move water, if it will not start after the power check, or if water keeps rising. Call if the pump is old and has needed attention more than once. The sump pump repair and installation page explains testing, replacement and backup options. A battery or water-powered backup can keep the pit pumping during an outage.
Choosing a replacement pump
Pumps come in two main types. A submersible sits in the pit and is quiet. A pedestal motor sits above the pit and is easier to reach. Capacity should match how fast water enters the pit and how high it has to lift. A plumber can size the pump to your pit and your discharge line. Check valves matter too, since a bad one lets water run back into the pit.
Backup power and alarms
Storms that bring water often take out power as well. A battery backup or a water-powered backup keeps the pit working when the main pump cannot. A water level alarm costs little and gives you a warning before the pit overflows. Ask about both when a pump is replaced.
Where the discharge should go
The outlet should carry water well away from the foundation. If it empties near the house, the same water can soak back into the ground and return to the pit. Many cities do not allow a sump pump to connect to the sanitary sewer. Ask the building department before changing the discharge.
A damp basement is not always groundwater
If the pit stays dry but the floor is damp, a plumbing leak may be the source. A supply line, a water heater or a failed drain can all wet a slab. A meter check with everything off tells you quickly. See leak detection if the meter moves while all fixtures are closed.
A twice-a-year routine
Test the pump before spring runoff and again in the fall. Pour water in until the float lifts, and confirm the pump runs and shuts off. Look at the pit while you are there. Remove silt and gravel, check the cord and listen for unusual noise. Five minutes twice a year can prevent a flooded floor.
Keep the lid and the cord tidy
A pit lid keeps debris and children out. Tie the cord up so it cannot tangle with the float.
If water already reached the floor
Standing water is a cleanup job. Move belongings off the floor, photograph damage and start drying. Wet drywall and carpet need attention quickly. Plumbing stops the source. Drying and cleanup is a separate service. See water damage restoration.
Sources
Local facts on this page come from public documents.
Quick answers
The impeller may be jammed, or the motor may be failing. Unplug the pump before you touch it.
Test it before the wet season and after any long dry spell. Pour water into the pit and watch it run.
A backup keeps the pit pumping when the power goes out. Ask about it if your basement has flooded before.
It can strain it. Thaw the outlet safely and consider rerouting the line.
It depends on use and the pump type. A pump that has needed repeated fixes is worth replacing.
Sump pump trouble?
Call and describe what the pump does when water enters the pit.