The short answer
A well pressure tank holds water under a cushion of air so the well pump at a Northern Virginia home doesn’t have to start every time someone opens a faucet. When the tank loses that air, it fills with water and the pump starts and stops every few seconds. That’s called waterlogged. The signs are a pump clicking on and off fast, pressure that pulses in the shower, a gauge that jumps, or water coming out of the tank’s air valve. A tank that only lost its air can be recharged. A tank whose bladder failed gets replaced.
Signs the tank is failing
- The pump clicks on and off every few seconds while water runs, instead of running a minute or more.
- Shower pressure pulses: strong, weak, strong.
- The gauge by the tank climbs and drops fast.
- Water, not air, spits out when you press the pin in the tank’s air valve. The bladder inside has torn.
- Tap the tank from the bottom up. A healthy one sounds dull where the water is and hollow where the air is. Dull all the way up means it’s full of water.
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Why it matters to the pump
Washington State public health guidance puts it plainly: a 1 to 5 horsepower pump shouldn’t start more than about six times an hour, and a waterlogged tank can make it start every few seconds. Franklin Electric rates motors up to 3/4 horsepower for at most 300 starts a day, and a failed tank can burn through that in a morning. The tank is often the cheaper part to replace, and the pump is the expensive one. That’s why a clicking pump is worth a call before it’s a dead pump.
Check the air charge yourself
- Turn off the breaker for the well pump.
- Open a faucet and let it run until the water stops, so the tank is empty.
- Take the cap off the tank’s air valve and check it with a tire gauge.
- It should read 2 psi under your switch’s cut-in: about 28 for a 30/50 switch, 38 for a 40/60.
- If it’s low, add air with a bike pump or a compressor, close the faucet, turn the breaker back on and watch a full cycle.
If the charge was low and holds after you fill it, you’re done. If it’s low again in a week, or water comes out of the valve, the bladder has failed, and a failed bladder can’t be fixed. The tank gets replaced.
What a new tank costs
Our plumbers replace a well pressure tank for $2,200 to $2,950. From about $37 a month at 0% APR for 60 months, the whole price financed, on approved credit. That covers a new well pressure tank sized to the pump, a new tank tee with gauge and relief valve, the air charge set to the switch, and the old tank hauled away.
We test the pump and the switch first, so you replace only what failed. If the pump and the tank both went in twenty years ago, doing them together can be the better call, and our well pump price page shows those prices. Not sure what you have? The well pump estimator asks a few questions and gives you a range.
When it’s not the tank
If the tank checks out and the pump still clicks fast, look at the switch: well pump pressure switch problems. If the pressure is just low everywhere, start with low water pressure on a well. If the water stopped altogether, what to check when a well pump stops working starts at the breaker. And after any work on a well system, Virginia Cooperative Extension recommends shock chlorinating the well, then testing for bacteria again one to two weeks later. Our well pump page has the whole system.
Book it
A plumbing diagnosis visit is $49, or $250 after hours, and you get the price of the fix before we start. Call (703) 997-9757, day or night, or book online with the problem already filled in. Every current deal is on our offers page. Rated 5.0 stars across 1,138 reviews on Google, Angi, Yelp, the BBB and Facebook, Virginia Class A license 2705192276.
Questions people ask
How do I know if my well pressure tank is bad?
The pump clicks on and off every few seconds when water runs, the pressure pulses, or water comes out of the air valve. Tap the tank: dull all the way up means it’s full of water.
What should the air pressure be in a well pressure tank?
With the pump off and the tank empty, the air charge should be 2 psi under your switch’s cut-in: about 28 psi for a 30/50 switch, 38 for a 40/60.
Can a waterlogged pressure tank be fixed?
If it only lost air, you can recharge it. If the bladder inside has torn, it can’t be repaired, and the tank gets replaced.
Will a bad pressure tank damage my well pump?
It can. A waterlogged tank makes the pump start every few seconds instead of a few times an hour, and too many starts overheat the motor and wear it out.
How much does a well pressure tank replacement cost?
Our plumbers replace one for $2,200 to $2,950, with a new tank tee, gauge and relief valve, the air charge set to the switch and the old tank hauled away. From about $37 a month at 0% APR for 60 months, the whole price financed, on approved credit.
