Newly installed sump pump sitting in a basement sump pit

Battery backup sump pump alarm

Backup controllers alarm for four main reasons: no AC power, low or failed battery, blown fuse, or the backup pump had to run. A backup pump run means the primary pump needs attention now.

Single source ~30 min easyBrands: Basement Watchdog, Wayne, Zoeller, Liberty, Others

Before you start

Batteries can release hydrogen gas; no sparks near the battery
Wear eye protection when servicing wet-cell batteries

Diagnostic steps

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OnCall Tech is a reference tool for trained technicians and can make mistakes. Always disconnect power and confirm with the manufacturer's documentation before you work.

More sump & well pumps guides

Guide · Sump / Well Pump

Sump pump trips the GFCI or breaker

A GFCI that trips with a sump pump is usually detecting real current leakage from a pump motor taking on water, a damaged cord or splice, or another load on the same circuit. Isolate the pump from the circuit before blaming the GFCI, and never bypass the protection on a pump in water.

4 steps ~45 minmoderate

Guide · Sump / Well Pump

Sewer or musty smell from the sump pit

A clean sump pit should not smell like sewage. Most odors come from a pit that has dried out and no longer seals the drain tile lines, stagnant water, organic buildup, or nearby plumbing traps that have dried or been siphoned. A strong, persistent sewage smell can mean a leaking sewer line near the pit.

6 steps ~30 mineasy

Guide · Sump / Well Pump

Sump pump keeps cycling when it has not rained

The most common cause is water returning from the discharge pipe through a failed or missing check valve, so the pump moves the same water again and again. Other causes are a small basin, a float set too close, a high water table or a leak feeding the pit.

4 steps ~40 mineasy