Why Does My Sump Pump Run Constantly?

In low-lying areas of Southern Maryland — particularly near the Chesapeake Bay, tidal creeks, and wetlands — a high water table is simply a fact of life. During heavy rain events or periods of sustained wet weather, a sump pump running every 5–10 minutes is doing exactly what it's supposed to do. If your pump runs frequently only during rain or wet seasons and your crawlspace or basement stays dry, the system is working correctly.

If your pump runs constantly regardless of weather, or if it runs frequently but your crawlspace is still wet, something is wrong. The most common causes: a failed check valve that lets water flow back into the pit after each pump cycle (causing the pump to immediately refill and run again), a pump that's too small for the water volume, a pit that's too small, a broken or disconnected discharge line, or a pump that's lost prime and is running dry.

A failed check valve is the single most common cause of a sump pump that runs constantly. The check valve prevents water in the discharge line from flowing back into the pit when the pump stops. When it fails, the pump empties the pit, stops, and then 5–10 gallons of water immediately flows back in from the discharge line — triggering the float switch again. The pump runs every few minutes indefinitely. Replacing a check valve is a straightforward repair that costs far less than burning out a pump motor.

If your primary pump is running constantly, your battery backup system is also cycling — draining the battery. During a power outage (exactly when you need the backup), the battery may be depleted. This is why addressing constant-running issues promptly matters beyond just the pump motor lifespan.