Many Bergen County basements stay dry only because of a pump in a pit in the corner. Heavy rain, a fast snow melt or the tail of a tropical storm raises the water in the ground, and the sump pump sends it back outside. Pumps fail without any warning, and nearly always at the moment they are needed. Testing one takes five minutes.
How it works
Groundwater collects in a pit set into the basement floor, called the sump. When the water lifts a float, the pump switches on and pushes the water up a discharge pipe and out of the house. A one-way valve on that pipe, the check valve, stops the water from running back down.
The five-minute test
Do this in early spring and again in late summer, before the storm season.
- Look in the pit. Remove stones, silt and anything that could jam the float or block the pump's intake.
- Check the power. The pump should be plugged into a working outlet, ideally one protected by a GFCI, and not into an extension cord.
- Pour in water. Slowly empty a five-gallon bucket into the pit. The float should rise, the pump should start, the water should drop quickly, and the pump should switch itself off.
- Listen. A steady hum is normal. Grinding, rattling, or a pump that runs without moving water is not.
- Go outside. Find where the discharge pipe ends. Water should be coming out, and it should be running away from the foundation, not pooling beside it. In winter, make sure the end is not blocked by ice or snow.
- Check the check valve. After the pump stops, a little water falling back is normal. A lot means the valve has failed, and the pump is doing the same work twice.
What usually goes wrong
- A stuck float. The pump has shifted in the pit, and the float is caught against the side.
- A tripped outlet. Press the reset button on the GFCI.
- A blocked or frozen discharge pipe.
- No power. The storms that flood basements also bring down power lines. This is the most common reason a good pump fails.
- Age. Most pumps last seven to ten years. One that is older than that and runs often is living on borrowed time.
A backup is worth having
If your basement is finished, or your pump runs in every heavy rain, consider a backup:
- A battery backup sump pump sits beside the main pump and takes over when the power goes out or the main pump fails. Test its battery when you test the pump, and expect to replace the battery every few years.
- A water-powered backup uses the pressure of the town water supply and needs no battery. It must be installed by a licensed plumber, with the correct backflow protection.
- A water alarm on the floor near the pit costs very little, and tells you there is a problem while it is still a small one.
Helping the pump
- Keep gutters clear, and extend the downspouts so that they empty several feet from the house
- Make sure the ground slopes away from the foundation
- In New Jersey a sump pump should discharge outdoors to your own property, not into the sanitary sewer. If yours is connected to a drain or a laundry sink, ask a plumber about it.
When to call a plumber
- The pump hums and moves no water, or will not start during the test
- It switches on and off every few seconds
- The pit fills faster than the pump can empty it
- You want a new pump, a backup, or a check valve fitted
When you are ready, find a licensed plumber near your town.