Sump pump alarm and backup options

What can go wrong with a sump pump

A sump pump sits in a pit in the lowest part of the basement or crawlspace. When groundwater rises, a float switch turns the pump on and sends water outside. It fails in four common ways: the power goes out, the float sticks or the switch wears out, the pump motor burns out, or the discharge line clogs or freezes. A fifth problem is quieter: without a check valve, water in the discharge pipe can flow back into the pit and make the pump cycle constantly. NDSU Extension notes that each pump should have a check valve on the outlet pipe, and that without it frequent cycling decreases the life of the pump.

What an alarm does, and what it does not

A pump alarm does not pump water. It tells you that something is wrong in time to act. Choose from these:

Place a high-water sensor a few inches above the normal switch-on level, well below the top of the pit and the floor. A leak sensor on the floor of the pit would trigger every cycle. Put a second sensor on the floor beside the pit to catch overflow.

Power-loss and energy monitoring

Many flooded basements happen during storms, exactly when the power fails. A power alert needs a sensor that still works on battery or a hub with a UPS: an outlet-powered device cannot warn you that it lost power unless it has a backup battery or the hub knows it went offline. If the pump plugs into a GFCI outlet, a nuisance trip also kills the pump. Reset it and consider a GFCI-protected circuit that an electrician can verify. An energy-monitoring plug can show whether the pump runs at all; check the pump’s amps first. Read the amps on your pump’s label and stay within the plug’s limit (see smart plug energy monitoring). Never plug a pump into an undersized plug-in device or an extension cord.

Backup options

NDSU Extension describes backup pumps that sit in the same sump and turn on only if the primary pump fails; electric backups run from a battery. Ready.gov’s flood advice is to install check valves and consider a sump pump with a battery. Practical points from NDSU:

• The battery should be a deep-cycle type; gel cell and AGM are preferred. An ordinary car battery is a poor fit except in an emergency.
• Runtime depends on battery size. In NDSU’s figures, a 40 amp-hour battery gives less than four hours of continuous pumping, and a 120 amp-hour battery about 11 hours. With intermittent pumping every four minutes, a 75 amp-hour battery lasted at least 60 hours.
• Check the battery voltage every six months; replace it if the voltage under load falls below 11.6 volts.
• For a long outage, a small generator can run the pump and charger. Use it outdoors only: the CPSC says generators must be at least 20 feet from the home.

An alarm and a backup pump belong together: the alarm tells you the backup is running and the battery is draining.

Test routine

1. Every three months and before storm season, slowly pour water into the pit until the float lifts and the pump starts. NDSU suggests cycling it at least twice.
2. Replace the pump if it sounds like it is pumping gravel or the float is sluggish.
3. Check that the discharge pipe is clear and carries water away from the house.
4. Test the alarm by raising the float or wetting the sensor, and confirm your phone alert and siren.
5. Check the backup battery and the charger indicator.

Insurance and renters

Ask your insurer how it treats water backup and sump pump failure, and which devices qualify for a discount; see smart home insurance discounts. Renters should tell the landlord about a failed pump: it is usually the landlord’s equipment, so a sensor on the floor beside the pit is a sensible low-cost addition. Wiring a pump permanently is a job for a licensed electrician. A set of sensors for the whole house is in the water leak protection kit.