Well Water Systems Troubleshooting Reference

Why this matters

About 13% of US households use a private well. Wells have more failure modes than municipal supply - pump, pressure tank, switch, foot valve, casing, drop pipe. The plumber who understands the system diagnoses quickly + avoids the trap of replacing the wrong component. This is the field card.

System overview

Components: pump (submersible OR surface jet) lifts water from the aquifer; pressure tank stores pressurized water so the pump doesn't run for every faucet open; pressure switch cycles pump on at cut-in, off at cut-out; foot valve / check valve keeps the drop pipe primed; pitless adapter routes supply below frost line; bladder inside pressure tank separates air + water (when it fails the tank waterlogs).

Common cut-in/cut-out: 30/50 PSI or 40/60 PSI. Tank pre-charge air pressure: 2 PSI below cut-in.

The most common complaint: short-cycling

Customer says the pump kicks on every time anyone runs a faucet - clicks on and off rapidly during a single fixture's use.

Diagnosis: bladder-tank air pressure is gone (waterlogged tank). The tank now stores almost no water under pressure, so the pump cycles on every flow.

Test: shut off pump at breaker, drain a faucet to fully discharge tank pressure, then check the Schrader valve on top of the tank with a tire gauge. Should read 2 PSI below cut-in (28 PSI for 30/50, 38 PSI for 40/60). If the reading is zero or near it, and water comes out of the Schrader instead of air, the bladder is ruptured - replace the tank (you can't field-replace the bladder on residential tanks).

If air pressure is just low but the bladder is intact, recharge with a bicycle or shop pump to spec; many tanks lose air slowly over years.

Don't replace the pump for this complaint. It's the most common misdiagnosis. The pump is doing its job - it's cycling because the tank no longer buffers.

Pump won't start

Walk the chain backward: breaker tripped (reset; if re-trips, motor likely shorted OR wire damaged underground); pressure switch contacts pitted/stuck (power off, inspect, replace if pitted); pressure already above cut-in (tank pre-charge too high OR switch maladjusted); jet pump start capacitor failed; open drop wire to submersible (megger from wellhead).

For submersibles, test motor at wellhead: winding resistance + insulation-to-ground. Open winding OR low insulation-to-ground = motor failed; both mean pulling the pump.

Pump runs constantly

Pump on, never satisfies the cut-out pressure:

• Leak somewhere in the system (drop pipe, supply line, fixture left open, toilet running)
• Pressure switch contacts welded closed - pump stays energized; replace switch immediately (motor will overheat)
• Pump losing prime (jet pumps) - foot valve failed; water draining back to well
• Drop pipe leak below ground (submersible) - pump must work harder; never reaches cut-out
• Wrong pump for the depth or demand (recently increased demand)

Verify by listening for leaks, isolating the system in sections, and checking pressure stability with everything shut off.

Low water pressure

Different from "pump won't start" - pump works, but pressure feels weak at fixtures:

• Pressure switch set too low (adjust the large nut for cut-in/cut-out range; small nut for differential)
• Sediment-clogged screens, filters, or aerators at fixtures (clean these first)
• Iron + manganese buildup in pipes restricting flow (older galvanized supply)
• Pump worn - impeller eroded; lower output. Common in sandy wells
• Drop pipe leak below ground reducing actual delivery

Customers often blame the well when the actual restriction is at the fixtures. Always check aerator before assuming whole-system issue.

Discolored or smelly water

• Red/brown: iron. Test water. Treat with oxidizing iron filter or softener (low iron) or aeration (high iron).
• Black: manganese (often with iron). Same treatment family.
• Rotten egg smell: hydrogen sulfide gas. Anion exchange, oxidizing filter, or aeration depending on level.
• Cloudy/turbid: sediment. Sediment filter (5 - 30 micron).
• Sandy: well screen failure or pump too close to bottom. Re-set pump higher, or new screen.
• Bacterial contamination: E. coli or coliform positive on lab test. Shock chlorinate the well; UV system or continuous chlorination for ongoing protection.

Test the water at a state-certified lab before recommending treatment - the customer's nose isn't a diagnostic tool. Water testing identifies the actual contaminants and their levels, which determine the right treatment.

When to pull the pump

Pulling a submersible pump is a significant job (often hundreds of feet of drop pipe). Reasons to commit:

• Motor electrical test confirms failure
• Pressure-test of drop pipe shows leak
• Pump won't deliver any water despite proven supply at the well
• System worked, then sudden total failure with motor unresponsive

Reasons NOT to pull the pump:

• Bladder tank waterlogged (replace tank)
• Pressure switch issue (replace switch)
• Above-ground leak (find it)
• Fixture-level pressure problem (clean fixtures)

A wrong pump-pull burns half a day for nothing. Always exhaust above-ground diagnostics first.

Common service mistakes

• Pulling the pump because the tank waterlogged
• Replacing the pressure switch without checking tank pre-charge
• Adjusting pressure switch beyond pump's safe operating range
• Recommending whole-system replacement for a fixture-level pressure issue
• Skipping water test before quoting a treatment system
• Not megger-testing the motor before declaring it dead
• Forgetting to chlorinate after any well intrusion (per code)

Customer education

The pressure tank is a maintenance item, not a fixture - they lose air pressure over years and eventually need replacement. The pump is mostly maintenance-free unless something fails; expect 15 - 25 years of service from a quality submersible if water quality is decent. Acidic water shortens pump life; abrasive (sandy) water destroys impellers. Treatment that addresses water chemistry extends pump life.

References

• NGWA (National Ground Water Association) standards
• Well Pumps + Pressure Tank manufacturer data (Goulds, Grundfos, Franklin Electric, Sta-Rite)
• State + county well code (annual testing requirements vary)
• EPA private well guidance
• Manuall internal: Common Pump Types, Water Pressure + Flow Reference