Well pump and water system service

The parts of a well system

Understanding the pieces makes the symptoms far easier to read, and most of them can be checked without going near the well itself.

The pump. Either a submersible, sitting down in the casing below water level and pushing up, the standard on deeper Texas wells, or a jet pump at the surface drawing water up, used on shallower wells.

The drop pipe and wiring running down the casing to a submersible. Pulling these is the expensive part of any submersible repair.

The pressure tank. A tank with an air bladder that stores water under pressure so the pump is not starting every time someone opens a tap. It is the component most often at fault when a system misbehaves, and the cheapest to replace.

The pressure switch. A small box, usually on the pipe near the tank, that starts the pump at a cut-in pressure and stops it at cut-out, commonly 30/50 or 40/60 psi. Cheap, and a common failure.

The control box on many submersible installations, containing the start capacitor and relay.

The check valve that stops water draining back down the well when the pump stops.

The pitless adapter, the below-ground fitting where the line leaves the casing beneath the frost line.

The wellhead itself, which should be capped, sealed, above grade, and not sitting in a depression that collects surface water.

Reading the symptoms

No water at all. Check the breaker first, well pumps trip them and it is free to rule out. Then the pressure switch contacts, then the control box, then the pump. On an older well in a dry year, also consider that the water level may have dropped below the pump intake.

Pump runs constantly and never shuts off. Either it cannot reach cut-out pressure or the switch has failed closed. Causes are a worn pump, a leak in the drop pipe, a failed check valve letting water fall back, a stuck switch, or a genuine leak somewhere on the property. Shut it off. A pump running continuously against no pressure destroys itself quickly.

Short cycling: on and off rapidly. Almost always the pressure tank. The bladder has failed and the tank is waterlogged, so there is no cushion and the switch trips within seconds either way. This is the single most common well system fault, and it kills pumps through sheer start frequency.

Air spitting from the taps. A drop in water level with the pump drawing air, a leak in the suction side on a jet pump, or a waterlogged tank. On a well that has never done it before, it deserves prompt attention.

Sand or grit. A failing well screen, or a pump set too close to the bottom of the well. Sand wears pumps and fixtures fast.

Low pressure everywhere. Pressure switch set low, a failing pump, a partly blocked filter, or a leak.

Dirty or discoloured water after rain. A serious sign. It suggests surface water entering the well, which is a contamination question rather than a plumbing one. Stop drinking it and get it tested.

The pressure tank: check this first

More well service calls resolve to the pressure tank than to anything else, and the checks are quick.

Tap it. A healthy tank sounds hollow at the top and dull at the bottom, with a clear transition. A tank that sounds dull all the way up is full of water and the bladder has failed.

Check the air valve. There is a schrader valve on the top, like a tyre valve. Press it. Air means the bladder is intact. Water means it has ruptured and the tank needs replacing.

Check the pre-charge. With the system depressurised, the tank's air charge should be 2 psi below the pump's cut-in pressure, 28 psi for a 30/50 switch. Almost nobody checks this, and a tank running at the wrong charge short-cycles the pump for years.

Count the cycles. Run a tap and watch the pump. It should run for a reasonable stretch and then rest for a reasonable stretch. On and off every few seconds is short cycling and it is doing real damage.

Size matters. A tank too small for the pump's output guarantees short cycling regardless of its condition. Draw-down volume should suit the pump, and undersized tanks are a common false economy on replacement.

When the pump itself is the problem

Testing before pulling. A great deal can be established from the surface: insulation resistance and winding resistance on the wiring, amperage draw when running, and voltage at the control box. These separate a failed pump from a failed capacitor, a bad splice or a wiring fault, which matters, because pulling is the expensive part.

Pulling a submersible. Everything comes up: pump, drop pipe, wiring, safety rope. On a deep well that is hundreds of feet of pipe and it needs equipment. It is the reason a well pump job costs what it does.

What gets replaced while it is out. The pump, and usually the drop pipe, the wiring and the check valve. Putting a new pump back on forty-year-old galvanised drop pipe and aged wire is asking to pull it all again. This is not upselling; it is the economics of the pull.

Sizing the replacement. Depth to water, total lift, required flow, and the pressure the house needs. An oversized pump is not better. It over-pumps the well, draws the level down and can pull sand and air.

Setting depth. Deep enough to stay submerged as the water level fluctuates seasonally, high enough above the bottom to avoid drawing sediment.

Jet pumps are at the surface and much easier to service. They lose prime, which submersibles do not, and a jet pump that will not prime usually has a leak on the suction side or a failed foot valve.

Typical life. Eight to fifteen years for a submersible, longer where the tank is healthy and the pump is not being short-cycled. Sandy water and frequent starts both shorten it substantially.

Water quality on a private well

Nobody tests it for you. That responsibility sits with the owner, and on a well it is not optional.

Test annually for bacteria and nitrates at minimum. More broadly, iron, manganese, hardness, pH, total dissolved solids, sulphide, every few years, and immediately after any work on the well, any flooding, or any change in taste, smell or colour.

Bacteria means the well has been contaminated, often through a compromised cap, a cracked casing, or surface water reaching the aquifer. Shock chlorination plus fixing the entry point, then a retest.

Nitrates point at agricultural or septic influence. Important for infants in particular, and not removed by ordinary filtration.

Iron and manganese cause staining and discolouration and need oxidation and filtration, not carbon.

Hydrogen sulphide is the rotten-egg smell. Treatable, and worth confirming it is the well rather than the water heater's anode rod, which produces an identical smell on the hot side only.

Hardness is usually high on Texas wells and the treatment is the same as on municipal supply.

UV disinfection is standard practice on wells and needs clear water to work, so it always goes last in the treatment train.

Protect the wellhead. Sealed cap, casing above grade, ground sloping away, and no chemical storage or livestock nearby. Most bacterial contamination arrives from the surface a few feet away rather than from the aquifer.