Well Pump Won't Turn Off: Pressure Switch Fixes

Your well pump is running and running—and won't shut off. This isn't just annoying, it's damaging your system. Here's what's causing it and how to fix it.

How the Pressure Switch Works

Understanding the system helps you diagnose the problem:

1. Cut-in (turn on): When pressure drops to the lower setting (typically 40 PSI), switch contacts close, pump starts
2. Cut-out (turn off): When pressure rises to the upper setting (typically 60 PSI), switch contacts open, pump stops

A 40/60 switch has a 20 PSI differential. Common settings are 30/50 or 40/60.

If the pump won't turn off, either:

• The switch contacts are stuck closed (mechanical failure)
• The system can't reach cut-off pressure (pressure problem)

Common Causes

1. System Can't Build Enough Pressure

Most common cause. The pump runs continuously because it can't reach the cut-off pressure.

Causes of low pressure:

• Leak in system: Water escaping somewhere (running toilet, broken pipe, open faucet)
• Failing pump: Worn impellers can't build full pressure
• Low well yield: Well can't supply water as fast as pump moves it
• Clogged pipes: Restriction limits flow
• Cut-off set too high: Pump can only make 55 PSI, switch set to 60

How to diagnose: Watch the pressure gauge. If it climbs slowly and never reaches cut-off (or hovers below it), you have a pressure problem, not a switch problem.

2. Stuck Switch Contacts

The electrical contacts inside the switch can weld together or corrode in the closed position.

Causes:

• Electrical arcing over time
• Insect or debris contamination
• Corrosion from moisture
• Age and wear

How to diagnose: With breaker OFF, tap the switch lever. If contacts are visibly stuck or show burn marks, replace the switch.

3. Waterlogged Pressure Tank

When the tank loses its air charge:

• Tank fills completely with water
• Pressure spikes instantly when pump runs
• Then drops instantly when any water is used
• Pump cycles rapidly, may not reach stable cut-off

How to diagnose: Tap the tank—if solid (not hollow), it's waterlogged. Or check air pressure at the valve (should be ~38 PSI when empty).

4. Clogged Sensing Port

The pressure switch has a small tube/port that senses system pressure. If blocked:

• Switch can't detect actual pressure
• May never trigger cut-off

How to diagnose: Remove switch and check the port opening for sediment or debris.

5. Misadjusted Settings

If someone adjusted the switch and set cut-off too high:

• Pump runs trying to reach impossible pressure
• System may have pressure relief valve that limits max pressure

How to diagnose: Check settings (nuts on top of switch) against pump capacity and original specs.

Diagnosis Steps

Step 1: Turn Off Power

Flip the breaker. Safety first, and stop the motor damage.

Step 2: Check Pressure Gauge

Note the reading. Is it at/above cut-off (60 PSI)? Or below?

• At or above cut-off: Switch is stuck (contacts welded)
• Below cut-off: System can't build pressure (leak, pump, or tank issue)

Step 3: Check for Leaks

With pump off, watch the pressure gauge. Does it drop?

• Drops slowly: Leak somewhere in system
• Drops fast: Large leak or check valve not holding
• Holds steady: No leak, pressure issue is elsewhere

Step 4: Inspect the Switch

With power OFF:

• Remove cover (small plastic box on gray square housing)
• Look for burnt contacts, debris, insects
• Check for corrosion or water damage

Step 5: Test the Tank

With power off and pressure drained:

• Check air pressure at the tank's air valve
• Should be 2 PSI below cut-in (38 PSI for 40/60 switch)
• If zero or very low, bladder may have failed

Fixes

If Switch Contacts Are Stuck

Replace the switch. Cost: $15-$40 for switch + installation.

Temporary fix: With power OFF, manually separate contacts with insulated screwdriver. This only works briefly—replace the switch promptly.

If Can't Build Pressure (Leak)

• Check all toilets (most common leak)
• Check irrigation system
• Listen for running water with everything off
• Check water meter for movement

If Tank Is Waterlogged

Replace the tank. Cost: $300-$800 installed.

If Pump Can't Build Pressure

• Check pump age (10-15 years typical life)
• Worn impellers require pump replacement
• May need professional diagnosis

Prevention

• Replace pressure switch every 10-15 years proactively
• Keep switch dry—seal wellhead properly
• Check tank air pressure annually
• Fix small leaks promptly

We service all major pump brands including Franklin Electric, Grundfos, Goulds (Xylem), and Sta-Rite (Pentair). Our trucks carry common parts and components for same-day repairs.

Frequently Asked Questions