In-depth guide
Well Pump Runs Constantly but Pressure Won’t Build: A Leak-Path and Pressure Containment Guide
When a well pump runs continuously but never reaches cutoff pressure, water is escaping or pressure isn’t being contained. This guide shows how to diagnose the leak path safely, protect the pump, and fix the root cause without guesswork.
In this guide
A well pump that runs nonstop without building pressure is under severe stress. Many homeowners assume the pump itself has failed — but in most cases, the pump is doing exactly what it’s told. The real problem is that pressure cannot be contained.
Letting a pump run continuously can overheat the motor, wash out internal components, and lead to total failure. The correct response is not to “let it run and see,” but to shut it down and diagnose the system methodically.
This guide explains:
- How pressure is supposed to build and be held
- Where pressure commonly escapes
- How to find the leak path step by step
- When to stop DIY to avoid destroying the pump
How Pressure Is Supposed to Build in a Well System
When the pump turns on, water is forced into a closed system consisting of:
- The drop pipe and check valve
- The pressure tank
- The house plumbing
As water enters, pressure rises steadily until the pressure switch cutoff is reached (commonly 40–60 PSI or 50–70 PSI). At that point, the switch shuts the pump off.
If pressure never rises, or rises very slowly and never reaches cutoff, water is escaping somewhere or pressure is not being stored.
Immediate Action: Protect the Pump
If the pump is running constantly:
- Turn off the breaker and allow the pump to cool
- Do not bypass the pressure switch
- Do not leave the system running unattended
Continuous operation is one of the fastest ways to destroy a well pump.
The Most Common Causes (Ranked)
1. Major Plumbing Leak
Any significant leak prevents pressure from building.
- Underground service line leaks
- Burst pipes
- Failed fittings
Large leaks may not be visible if they occur underground or behind walls.
2. Ruptured Pressure Tank Bladder
A failed bladder allows water to fill the entire tank, leaving no air cushion to store pressure.
Symptoms include:
- Pump runs but pressure barely rises
- Pressure drops instantly when pump shuts off
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3. Failed Check Valve
The check valve prevents pressurized water from flowing back toward the well. If it fails, pressure bleeds off as fast as the pump creates it.
4. Broken Drop Pipe or Fitting in the Well
Water may be pumped directly back into the well if the pipe has separated or cracked.
This requires pulling the pump.
5. Pump Wear or Internal Damage
Impeller damage reduces the pump’s ability to move water but is less common than leaks or containment failures.
Step-by-Step Diagnosis (Follow This Order)
Step 1: Shut Off All Water Usage
Ensure no fixtures are drawing water. Pressure should rise if the system is sealed.
Step 2: Watch the Pressure Gauge
Restore power briefly and observe pressure behavior.
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- No rise at all → major leak or failed tank
- Slow rise, never reaches cutoff → leakage or weak pump
- Rises then immediately falls → check valve or tank issue
Step 3: Isolate the House Plumbing
Close the main shutoff valve to the house.
- If pressure now builds → leak in the house or service line
- If pressure still won’t build → problem is before the valve
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Step 4: Test the Pressure Tank
With the system depressurized:
- Tap the tank — hollow sound at top is normal
- Water at the air valve indicates bladder failure
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Step 5: Inspect for Hidden Leaks
Check crawlspaces, basements, and yard areas near the service line.
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Why Replacing the Pump First Is a Mistake
Replacing a pump without fixing leaks or pressure containment issues will:
- Destroy the new pump prematurely
- Fail to restore pressure
- Waste significant money
Always confirm pressure can be held before condemning the pump.
When This Is No Longer DIY
Call a professional if:
- The pump must be pulled
- The drop pipe or check valve is suspected
- Pressure cannot be isolated to the house
Preventing This Problem in the Future
- Replace aging pressure tanks proactively
- Install leak detection for early warnings
- Monitor pressure switch behavior
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Final Takeaway
A pump that runs constantly without building pressure is almost always fighting a leak or containment failure. Diagnosing the pressure path carefully protects the pump and leads to the correct fix — without unnecessary replacements.
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