Pressure Tank Waterlogged: Fix Your Well Pump Problems

1. Low or Missing Air Charge in the Tank (Easiest Fix)

Bladder-style pressure tanks require a pre-charge of air (typically 2 PSI below the pump’s cut-in pressure). If the air charge bleeds off over time, the tank behaves as if it is waterlogged even if the bladder is intact.

1. Turn off the well pump breaker at your electrical panel.
2. Open a nearby faucet and relieve all water pressure in the system — wait until water stops flowing completely.
3. Locate the Schrader valve (looks like a tire valve) on the top or side of the pressure tank.
4. Use a tire pressure gauge to check the air pressure. A correctly charged tank should read 28 PSI if your cut-in pressure is 30 PSI (always 2 PSI below cut-in).
5. If pressure is low or zero, use a bicycle pump or air compressor to add air slowly. Do not exceed the rated pre-charge pressure printed on the tank label.
6. Restore power, let the pump cycle, and monitor for short-cycling. If the problem returns within days, the bladder is likely ruptured (see Cause 2).

2. Ruptured or Failed Bladder — The Classic Pressure Tank Waterlogged Cause

The rubber bladder inside the tank separates the water from the air cushion. When it ruptures or cracks, water floods the entire tank and you get the classic pressure tank waterlogged symptom: rapid pump short-cycling and no sustained pressure.

1. With the pump off and pressure relieved, remove the Schrader valve cap and depress the valve core with a small screwdriver.
2. If water (not just air) sprays out, the bladder has failed and the tank must be replaced or rebuilt.
3. Note the tank’s gallon capacity and pressure rating before purchasing a replacement (commonly 20, 30, 44, or 86 gallons).
4. Shut off the main water supply valve. Drain the tank fully by opening a low faucet.
5. Use two pipe wrenches to disconnect the tank from the supply line fitting. Have towels ready for residual water.
6. Install the new tank with thread-seal tape on all male threaded connections. Tighten firmly but do not over-torque.
7. Pre-charge the new tank’s air bladder to 2 PSI below your cut-in pressure before reconnecting water.
8. Restore water supply and power, then check for leaks and confirm the pump cycles correctly (cut-in around 30 PSI, cut-out around 50 PSI for a standard 30/50 switch).

3. Faulty Pressure Switch

The pressure switch tells the pump when to start and stop; if its contacts are pitted, corroded, or the set-points have drifted, the pump may cycle erratically even after the tank is correctly charged.

1. Turn off the pump breaker. Remove the plastic cover from the pressure switch (usually a single screw or snap-off cap).
2. Inspect the electrical contacts inside for black pitting, burns, or corrosion. Pitted contacts prevent the switch from opening or closing reliably.
3. Check the cut-in and cut-out settings by consulting the adjustment nuts inside. The larger nut adjusts both set points; the smaller nut adjusts the differential.
4. If contacts are heavily pitted, replace the switch. Standard switches are rated 30/50 PSI or 40/60 PSI — match your existing setting.
5. With power OFF, remove the two wires from the pump (label them first), swap in the new switch, reconnect wires, restore power, and test.

4. Failed Check Valve or Foot Valve

A check valve prevents pressurized water from flowing back down into the well when the pump is off. If it fails, pressure drops immediately after every pump cycle, stressing the pump and mimicking a waterlogged tank.

1. After the pump reaches cut-out pressure, turn the breaker off and watch the pressure gauge. A healthy system holds pressure for many minutes; a drop within 30 seconds points to a check valve failure.
2. Locate the inline check valve — usually within the first few feet of pipe above the well casing or inside the pump itself.
3. Shut off power and relieve pressure. Remove the check valve using pipe wrenches and inspect the internal rubber flapper or ball for cracks or debris.
4. Install a new same-size check valve with flow-direction arrow pointing toward the pressure tank. Use thread-seal tape on all connections.
5. Restore power and re-test; pressure should now hold between pump cycles.

5. Waterlogged Pressure Tank Due to Oversized or Undersized Tank

If the tank drawdown capacity is too small for your pump’s flow rate, the pump short-cycles even with a perfect bladder — exactly mimicking a waterlogged state and accelerating premature pump wear.

1. Find your pump’s flow rate in gallons per minute (GPM) — check the pump label or your original well driller’s report.
2. Use the rule of thumb: minimum drawdown (usable gallons) = pump GPM × 1 minute. A 10 GPM pump needs at least 10 gallons of drawdown.
3. Check your current tank’s drawdown rating on its label (not total capacity — drawdown is typically about 30% of the total gallon rating for a bladder tank).
4. If undersized, add a second tank in parallel or replace with a correctly sized unit. Do not mix tank types (steel vs. bladder) in parallel without guidance.
5. After installation, set the air pre-charge on both tanks identically, 2 PSI below cut-in pressure.

6. Worn or Failing Submersible Well Pump

An aging submersible pump that can no longer maintain adequate pressure or flow will cause your system to struggle even when the tank, switch, and valves are all in good condition.

1. Verify all other components are functioning correctly before suspecting the pump itself — this is the most expensive fix.
2. Check the pump’s output: attach a flow meter or time how long it takes to fill a 5-gallon bucket at a hose bib. Significant reduction from the rated GPM indicates pump wear.
3. Measure the voltage at the pump’s pressure switch with a multimeter while the pump runs. Voltage should match the pump’s rated voltage (typically 240V). Low voltage causes weak output and overheating.
4. Listen for unusual noises (grinding, humming with no water flow) which indicate motor or impeller damage.
5. If the pump is confirmed faulty, pulling a submersible pump requires specialized equipment. Contact a licensed well contractor for this repair.

Frequently asked questions