Well Pump Losing Prime? Here's What's Really Happening

A well pump "loses prime" when the solid column of water between the pump and your taps breaks and air gets into the line instead. You will usually notice the pump running, sometimes normally and sometimes straining, while the faucet sputters, drips, or gives you nothing at all. On most South Carolina homes with a drilled well and a submersible pump, this traces back to a check valve that has stopped sealing, letting the water in the drop pipe slide back down the well every time the pump shuts off, and it tends to show up first right after a storm knocks the power out and the pump has to restart cold. Do not keep flipping the pump on and off hoping it clears itself. A submersible pump that spins dry, even for a few seconds at a time, can burn out its motor, and the actual fix means opening the wellhead safely, not guessing at it from the kitchen.

What does it mean when a well pump loses prime?

Losing prime means the pump has lost its grip on a continuous column of water and started pulling air instead. A pump, whether it sits above ground on a shallow well or hangs down a drilled well as a submersible unit, moves water by pushing against a column that is already full and connected all the way to the tap. Break that column anywhere, with an air leak, a valve that will not hold, or a well that has run temporarily low, and the pump spins against air pockets instead of water. You get inconsistent pressure, a pump that sounds like it is working harder than it should, or a tap that runs a few seconds of water followed by sputtering and nothing. Homeowners often describe it exactly that way to us: the pump clearly runs, the gauge shows some pressure, and the water still will not come.

Why does this happen more right after a storm or power outage?

A storm-driven outage forces the pump to do a cold restart, which is exactly when a weak check valve gets exposed. While the pump runs, the check valve holds the water column up in the drop pipe against gravity. Cut the power, even for a few minutes, and a check valve that is already worn or debris-fouled will let that water column slide back down toward the pump instead of holding it in place. When the power comes back, the pump has to refill that entire column before water reaches the tap again, and if the valve keeps leaking, it never fully catches up. South Carolina's summer storm pattern makes this common: frequent afternoon lightning across the Midlands and Upstate means frequent short outages, and a check valve that has been marginal for months can go from "fine" to "no water" the very next time the lights flicker.

Is this the same problem a shallow well has?

Not exactly, and this is the part most guides skip. Most articles on this topic describe a shallow well jet pump: it sits above ground, pulls water up through a foot valve at the bottom of the suction line, and needs a fresh hand-primed water charge poured into the pump housing whenever that foot valve fails and air gets in. That is a real DIY-adjacent job on that specific kind of system. A drilled well with a submersible pump, which is what most Austin Drilling customers have, works differently: the pump itself sits underwater at the bottom of the well, so it never needs the housing hand-primed the way a jet pump does. What actually fails is a check valve, either built into the pump or installed just above it, that is supposed to keep the drop pipe full between cycles. When that valve leaks, the symptom looks the same from the kitchen (pump runs, water sputters or stops) but the fix is entirely different, and it lives down inside the well casing rather than on a pump housing you can reach from the yard.

Can you re-prime a well pump yourself?

For a shallow well jet pump, yes, within limits: shutting off the power, opening the priming plug, and refilling the housing with water is a task some homeowners handle themselves, following the pump manufacturer's instructions exactly. For a submersible system on a drilled well, no. There is no priming plug to refill, because the problem is a failed valve down the well or at the wellhead connection, not an empty pump housing. Getting to it safely means working around a live electrical drop and pulling or accessing equipment that may be dozens or hundreds of feet down, and doing that without cutting power correctly, or without the right tools to handle the drop cable, is how people get hurt or turn a valve replacement into a burned-out motor. If your water sputters and stops after a storm and you have a drilled well, treat it as a call, not a weekend project.

How do you stop it from happening again?

The lasting fix is replacing the check valve before it fails completely, not resetting the system every time it happens. A technician pressure-tests the line to confirm the valve is the actual culprit rather than a cracked fitting or a low-yielding well, then replaces the failed valve so the water column holds during the next outage instead of draining back down. If the well itself is running low during dry stretches, that is a separate issue worth ruling out with a flow check, since a well that occasionally runs low can produce the exact same symptom as a bad valve, and the two need different repairs. Either way, catching it now is cheaper than waiting for a repeat failure to take the pump motor with it, since a motor that spins dry repeatedly during every failed restart wears out far faster than one that never runs against air at all.

Is a pump that won't hold prime an emergency?

Treat it as same-day if you have no water at all, if it happens again within days of the last time, or if the pump sounds like it is straining every time it kicks on. A single sputter right after a storm that clears up on its own after a minute is worth watching, not panicking over. But a pump that will not catch after several attempts, especially paired with a hot or burning smell near the pressure switch, means stop resetting it and call. Austin Drilling has been pulling pumps and chasing this exact symptom across the Midlands and Upstate for 66 years, and a call during business hours (Mon-Fri 7am-6pm, Saturday by appointment) usually gets a technician out the same day to find the actual valve or well issue instead of you guessing at it one reset at a time.

Frequently asked questions

How do I know if my pump lost its prime versus something else being wrong?

The clearest sign is that the pump audibly runs, and the gauge often still shows some pressure, but the water at the tap sputters, drips, or cuts out entirely. A pump that will not even turn on points to a breaker or switch instead; our well pump not working guide walks through that different symptom.

Does losing prime mean I need a whole new pump?

Usually not. Most cases trace back to a single failed check valve, which is a far smaller repair than replacing the pump itself. The pump only gets damaged if it keeps running dry through repeated failed restarts, which is exactly why we tell people to stop cycling it and call instead.

Why does my pressure gauge still show a number if the pump lost its prime?

A pressure tank stores pressure separately from the well itself, so the tank can hold a reading for a little while even after the pump stops delivering fresh water. That stored pressure runs out fast once you start using taps, which is often the moment the problem becomes obvious.

Can a short power outage alone cause this?

Yes, on a system with a weak check valve. The valve is what should be holding the water column up during any restart, so any outage, long or short, is a stress test on a valve that may already be close to failing.

What does it cost to fix a well pump that keeps losing prime?

It depends on whether the fix is a single check valve or something further down the well, and the only way to know is a technician looking at the actual system. A stuck or worn valve is generally one of the less involved well repairs, but we would rather give you a real number after a look than guess over the phone. Call West Columbia at (803) 926-5402 or Newberry at (803) 926-7080 for a diagnosis.

Should I keep resetting the pump myself while I wait for someone to look at it?

No. Every reset that runs the pump dry, even briefly, adds wear a submersible motor was not built for. Shut it off, use stored water from pots or a water heater in the meantime, and let a technician find the real cause the first time.

If your water keeps cutting in and out after a storm, Austin Drilling's pump services team can trace it to the actual valve or well issue and get it fixed instead of reset. It is worth ruling out short cycling and a tripped breaker after a storm too, since all three can show up together after the same outage, and our no water from a well guide covers the full range of sudden-loss causes if you are not sure yet which one you are dealing with.