Is it my well pump or my pressure tank?

What each one does, so the symptoms make sense

The pump makes water. It hangs down the well on a submersible or sits above ground on a jet pump, and its only job is to push water toward the house until pressure reaches the cut-out setting on the switch. Then it stops and waits.

The pressure tank stores pressure so the pump doesn't have to start every time somebody washes their hands. Inside a modern tank is a rubber bladder with compressed air around it, and that air is a spring. Draw water and the air pushes it to your tap with the motor sitting still. The gallons the tank gives back between cut-in and cut-out are the drawdown.

Once you see it that way, the split is clean. Tank problems are about how often the pump runs. Pump problems are about whether there's water and how much pressure it can build. Almost every diagnosis on a well system comes back to sorting a symptom into one of those two buckets.

Two other parts sit in the middle and imitate both. The pressure switch tells the pump when to start and stop, and a switch with burned contacts or a plugged sensing tube produces symptoms that look exactly like a bad tank or a dead pump. The check valve holds water in the drop pipe between cycles, and a leaking one makes a perfectly good tank cycle on its own overnight.

What a dead tank looks like from inside the house

Short cycling is the headline symptom, and it's unmistakable once you know what you're listening for. A properly sized tank on a normal house gives you real drawdown, so running a shower means the pump kicks on, runs a minute or two, and shuts off. When the bladder tears or the air charge bleeds away, that storage is gone. The pump starts and stops every few seconds and the switch clacks along with it.

Pressure surging at the faucet is the other one. Strong, then weak, then strong again, in rhythm with the pump. A shower that can't hold a temperature because the cold side keeps pulsing is a tank symptom, not a water heater symptom.

There's a physical signature too. A waterlogged tank is heavy and cold to the touch all the way to the top, because there's water behind every inch of steel instead of air. Many of them sweat in humid weather and show soft rust at the bottom seam where condensation has been running off for years.

None of this hurts the tank much. It's already ruined. What it hurts is the pump, because every one of those starts is a moment of high current and mechanical shock in a motor a few hundred feet down.

What a dying pump looks like from inside the house

Zero pressure on the gauge that never climbs is the pump, the well, or the electricity feeding them. So is a pump you can hear running while the gauge sits still. So is a breaker that trips the instant you reset it. None of those are tank symptoms, because a tank with no air in it still passes water.

A worn pump gives you the subtler version. Pressure builds slowly and stalls out below cut-out, so the pump runs and runs and never shuts off. That's a pump that can no longer make its rated head, and it's common past twelve or fifteen years and on any well carrying sand. Long showers that start fine and fade are the household version of the same thing.

Air spitting at the tap with cloudy white water belongs to the well side. A pressure tank cannot introduce air into your water. A well drawing down to the pump can, and so can a leak on the suction side of a jet pump.

Grit in the aerators and sand in the toilet tanks is pump and well territory too. It tells you what the impellers have been chewing on.

The precharge check, with real numbers

This is the test that settles it, and any homeowner with a tire gauge can run it. Do it in this order, because the order is what makes the number mean anything.

Kill power to the pump at the breaker. Then open the lowest faucet in the house, a laundry sink or an outside hose bib, and let it run until it stops on its own. Watch the gauge on the tank tee. It has to reach zero and stay at zero. This is the step people skip, and skipping it wrecks the whole test, because any water pressure left in the tank adds itself to your air reading and makes a dead tank read healthy.

Now take the cap off the Schrader valve on top of the tank, the same stem as a car tire, and put a tire gauge on it. Compare what you read against the cut-in pressure stamped inside your pressure switch cover. The target is 2 psi below cut-in. On a 40/60 switch, 38 psi. On 30/50, 28. On 50/70, 48. That 2 psi gap lets the tank push its last water out just before the pump comes back on, which is how you get full drawdown.

Read the result. Right on target means the tank is fine and your trouble is somewhere else, most likely the switch, the sensing tube, or a leak. Fifteen or twenty psi means the tank has been slowly losing air and adding some back may be the entire repair. Zero means it's flat. And water coming out of that valve instead of air means the bladder is torn, which ends the investigation: there's no field repair for a torn bladder, and a tank swap is a same-day job in most basements.

One caution before you pump air into anything. If the tank sweats heavily, weeps at a seam, or shows soft rust at the bottom, leave it alone. A corroded tank holding 60 psi is a hazard, not a project.

Timing a cycle, thumping the tank, and reading the gauge

Time a cycle before you do anything else, because it costs nothing. Open one fixture at a normal flow and watch the gauge with a phone timer running. From the moment the pump kicks on to the moment it shuts off should be a minute or more. Six seconds is a tank with nothing in it. Thirty seconds is a tank that's low or undersized. Two minutes is a system doing its job.

The thump test takes another minute. Make a fist and rap your knuckles down the side of the tank from top to bottom, listening as the sound changes. A healthy tank rings hollow across the upper portion and goes dull where the water sits. Where the tone changes is the water line. Solid and dead from the very top means there's no air space left, and that's the whole diagnosis before you ever pick up a gauge.

Then read the gauge behavior, because it says something different in each failure. The needle sweeping the full range from 40 to 60 and back in seconds, over and over, is a tank. The needle climbing slowly and stalling at 45 with the pump still running is a worn pump. The needle at zero and never moving is a pump, a well or the electrical feed. The needle holding steady at cut-out while no water comes out of any faucet is a blockage or a closed valve downstream, not a pump problem at all.

One more pattern people misread. If the pump kicks on for a few seconds every twenty minutes overnight with nobody using water, and the tank tests fine, that's a leak. A running toilet flapper, a bad check valve letting the drop pipe drain back, or a break in the line between the well and the house. It looks like short cycling and it's a different repair.

For a contractor there's a fourth measurement: amp draw. Clamping a meter on the pump leg and comparing running amps against the nameplate tells you whether the motor is loafing, working normally, or straining. High amps with low pressure is a worn or bound pump. Low amps with low pressure often means it's spinning without moving water. That's the reading that turns a strong suspicion into a decision.

When it's genuinely both, and why proving it is worth twenty minutes

A dead tank kills pumps. Thousands of extra starts put heat and mechanical stress into a motor that was never meant to take them, and a pump that should have run fifteen years quits at nine. If the tank has been short cycling for a season and the pump is past a decade, expect both to be on the table and be suspicious of anyone who quotes only one.

It runs the other direction too. A pump pulling sand sends grit into the tank, where it abrades the bladder from the inside. A well that draws down pushes air into the system, and a tank fighting air slugs cycles harder than it should. On an iron heavy well, sediment settles into the bottom of the tank and shortens its life the same way it shortens the pump's.

Proving which one it is matters because the two jobs aren't remotely comparable. A pressure tank sits in your basement, ten feet from the panel, and swapping it is a couple of hours with no rig. A submersible in a deep rock well means pulling hundreds of feet of pipe, wire and pump out of the ground and putting it all back, and the pull and reset alone is the bulk of the invoice on a deep or difficult one.

We see it go wrong both ways. Tanks get swapped on houses where the pump was the real trouble, and the new tank cycles just as fast because nothing was fixed. Pumps get pulled on houses where a pressure switch would have done it. Air charge, amp draw and drawdown are three measurements that take about twenty minutes and settle the question. A diagnostic visit gets credited against the repair when we do the work.

If the pump still tests strong, replacing the tank alone is a legitimate choice and we'll price them separately so you can decide. There's no rule that says both have to go together. Call 973-853-1550 and tell us what the gauge does, what the tank sounds like, and what came out of the air valve.