Why Is My Sump Pump Running Constantly?

A continuously running sump pump is failing. These systems should cycle on and off based on water levels in your basement. Constant operation signals mechanical failure, incorrect sizing, or drainage problems that will damage your pump and leave your home vulnerable to flooding.

This guide identifies the specific causes of continuous sump pump operation and provides clear troubleshooting steps. You’ll learn when you can fix the problem yourself and when to call a professional before the pump fails.

What you’ll learn:

• The mechanical failures that prevent your pump from shutting off properly
• How incorrect system sizing forces constant operation
• Drainage issues that trap water in an endless cycle
• Warning signs that your pump is about to fail
• When to repair versus replace your system

Float Switch Failures Keep Pumps Running

Your float switch controls when the pump turns on and off. This device rises with water levels and activates the pump at a preset height. When the water drains and the float drops, the pump should shut off.

Three problems cause float switch failure:

1. Debris wedges the float in the raised position
2. The float tangles with power cords or catches on the basin wall
3. The switch mechanism wears out after years of use.

A stuck float keeps your pump running even after the pit empties. The motor continues at full power while pumping minimal water.

Float Switch Types and Performance

Switch Type	Space Required	Expected Lifespan	Common Issues
Vertical Float	18-24 inches	5-7 years	Sticks against basin walls
Tethered Float	24-30 inches	4-6 years	Tangles with cords and debris
Electronic Switch	Minimal	7-10 years	Most reliable, higher cost

How to diagnose:

Unplug the pump and inspect the float. Remove any debris wrapped around it. Move the float up and down manually. It should travel smoothly without catching or binding. If cleaning doesn’t fix the problem, replace the float switch. Electronic switches cost more but offer the longest lifespan and most reliable performance.

Undersized Pumps Cannot Keep Up

• Pump sizing determines how much water your system can remove per hour. An undersized pump cannot move water as fast as it enters the pit. The result: continuous operation as the pump struggles to keep pace.

• Residential sump pumps range from 1/3 HP to 1 HP. Most average homes need a 1/3 HP pump. Homes with high water tables, larger square footage, or deeper basements require 1/2 HP or larger systems.

• A 1/2 HP pump moves 35-40% more water than a 1/3 HP unit. The extra capacity handles higher water volumes and longer discharge runs.

Matching Pump Size to Your Home

Home Conditions	Recommended Horsepower	Capacity (GPH)	Maximum Vertical Lift
Average home, normal water table	1/3 HP	2,400-3,000	10 feet
Average home, high water table	1/2 HP	3,600-4,200	15 feet
Large home or flood-prone area	3/4-1 HP	4,800-6,000	25 feet

Testing for size problems:

Watch your pump during moderate rain. If it runs more than 50% of the time during typical wet weather, your system is undersized. Pumps working beyond capacity develop motor burnout. The average sump pump lasts 7-10 years, but an overworked system fails within months.

Check Valve Problems Create Water Loops

Check valves prevent water from flowing backward into your sump pit. This one-way valve sits on the discharge pipe above the pump. After each cycle, it closes to trap water in the line.

Without a working check valve, water flows back down after the pump stops. The pit refills immediately. The float triggers again. This endless loop runs your pump without actually removing water from your basement.

Check valves fail when the internal flapper wears out, debris prevents closure, or freezing temperatures crack the valve body. Some older installations lack check valves completely.

Signs of check valve failure:

• Pit refills within 10-20 seconds after the pump stops
• You hear water rushing back down the discharge pipe
• Pump cycles every 30-60 seconds during dry weather

Replace failed check valves immediately. Install the new valve with the directional arrow pointing away from the pump. Use ring clamps on both ends to secure connections.

Discharge Pipe Blockages Stop Water Flow

The discharge pipe carries pumped water away from your foundation. Blockages prevent water from leaving the system. Your pump runs continuously while water stays trapped in the pipe. Common causes include dirt and sediment buildup, frozen water in cold climates, debris at the exit point, and animal nests blocking the opening.

Discharge Pipe Problems and Solutions

Problem	When It Occurs	Prevention
Sediment buildup	Year-round	Flush the pipe annually
Ice blockage	Winter	Install freeze-resistant line
Debris at exit	Spring/Fall	Add a protective grate
Root intrusion	Growing season	Route away from trees and shrubs

Clearing blocked pipes:

Remove the discharge pipe from the pump outlet. Flush hot water through the line from the pump end outward. Use a plumber’s snake for stubborn blockages.

Prevention steps:

• Extend the discharge line at least 10 feet from your foundation
• Angle the exit point slightly upward to prevent debris entry
• Install freeze-resistant discharge line kits in cold climates

Small Sump Pits Force Rapid Cycling

• An undersized sump pit creates the appearance of continuous operation. The basin holds too little water. Your pump activates, empties the small volume, and shuts off. Within seconds, the pit refills, triggering another cycle.
• Standard sump pits measure 18-24 inches in diameter and 22-24 inches deep. Smaller pits cause cycling every 30-60 seconds.
• This rapid cycling damages pump motors. Each startup draws maximum electrical current and generates heat. Motors designed for intermittent use fail when forced to start hundreds of times daily.

Checking pit size:

Measure your pit during dry conditions. If the diameter is less than 18 inches, you need a larger basin. Pit enlargement requires professional excavation and installation.

When to Call a Professional

Some problems require expert help. Call a licensed plumber or waterproofing specialist for:

• Electrical problems: Tripped breakers, burning smells, or sparking connections
• Complete pump failure: When troubleshooting doesn’t restore function
• Pumps over 7-10 years old: Replace before failure causes flooding
• Foundation issues: Cracks in the pit, water seepage, or recurring flooding

According to industry data, 58% of homeowners need sump pump repairs within 1-2 days of a problem occurring. Don’t wait until your pump fails completely during a storm.

Maintenance Prevents Most Problems

Regular testing identifies issues before they cause failure. Follow this maintenance schedule:

Every Three Months:

• Pour water into the pit to test pump activation
• Verify the pit empties completely
• Check the discharge pipe outlet for blockages
• Watch the float for smooth up-and-down movement

Annually:

• Remove the pump and clean sediment from the basin
• Rinse the pit walls and bottom
• Check the intake screen for clogs
• Inspect the check valve operation

During Each Test:

• Document how long the pump runs
• Note gaps between cycles
• Compare patterns to previous tests

Changes in runtime patterns indicate developing problems that need attention.

Protect Your Home Now

A continuously running sump pump will fail. The only questions are when and how much damage it will cause. Start with basic troubleshooting: check the float, inspect the discharge pipe, and verify the check valve operation.

For issues beyond simple fixes, don’t risk your basement. Four Seasons offers 24/7/365 sump pump service throughout the Greater Chicagoland area. Our certified technicians diagnose and repair all sump pump problems with transparent, job-based pricing. No hidden fees, no surprises.

Call 866-4-SEASONS any time to speak with a live person who can help protect your home.