Well Pressure Tank Troubleshooting: Waterlogged, Short Cycling & Low Pressure
Number copied. Text it from your phone: 443-277-2204.
Well Water Pressure Tanks
Well Pressure Tank Troubleshooting: Waterlogged, Short Cycling & Low Pressure
Most pressure tank calls I take start the same way: "the pump keeps clicking on and off." About half of those tanks are actually bad. The other half are fine, and the caller was about to spend $1,300 on a problem they didn't have. Here is the exact sequence I walk people through on the phone, in the order I ask it, so you can find out which half you're in before you buy anything.
Quick Answer
A waterlogged pressure tank means the rubber bladder inside has torn and the air side has filled with water. It cannot be repaired; the tank gets replaced. But three of the five "bad tank" symptoms people call about are caused by something else, and two of those fixes cost under $30.
| What you notice | Most likely cause | What it costs to fix |
|---|---|---|
| Pump clicks on and off every few seconds while water is running; faucets spit or pulse | Waterlogged tank (torn bladder) | New tank, $1,095 to $2,195, about 2 hours of work |
| Pump runs longer than it used to; you have to add air every few weeks | Low air pre-charge or a slow bladder leak | Free if it holds; new tank if it doesn't |
| Pump starts every time you flush the toilet, then runs steadily | Normal for a standard-size tank | Nothing |
| Gauge stuck on one number no matter what you do | Clogged gauge port or dead gauge | $10 to $20 |
| Pump kicks on at 25 and off at 45 instead of 30/50; pressure never reaches the old high | Pump or pressure switch, not the tank | $15 to $30 for a switch; a well tech for the pump |
| Pressure bleeds down with everything off | Check valve or a leak | $20 to $50 part, plus labor if the pump has to come up |
If the tank is over 10 years old and shows either of the first two symptoms, replace it (what to buy is at the end). If you can't tell whether it's the tank or the pump, call or text me at 800-460-5810 and we'll figure it out in a couple of minutes.
If your tank turns out to be waterlogged, the Well-X-Trol tanks I sell come with the tee kit and a new switch.
The 60-Second Check (Do This First)
You can tell whether the bladder in a pressure tank has failed in about a minute, with a tire gauge and nothing else. Every other test on this page comes after this one.
- Turn the pump off at the breaker or the disconnect switch next to the tank.
- Open a faucet (a hose bib or laundry tub is easiest) and let it run until the pressure gauge on the tank tee reads zero and the water stops.
- Find the air valve on top of the tank. It looks exactly like the valve on a car tire. Unscrew the cap.
- Press a tire gauge onto it and read what comes out.
| What comes out of the air valve | What it means | Next step |
|---|---|---|
| Air, and the gauge reads about 28 PSI (30/50 switch) or 38 PSI (40/60 switch) | Bladder is intact and the tank is set correctly | The tank is not your problem. Go to tank, pump or switch. |
| Air, but the gauge reads well below 28 or 38 | Low pre-charge (the air pressure in the tank with the water drained out). Bladder may be fine or may have a pinhole. | Recharge with a compressor to the right number, mark the date, recheck in a week. See Problem 4. |
| Water sprays out | Bladder has torn. The tank is waterlogged. | Replace the tank. No repair exists. See Problem 1. |
| Nothing at all, no air and no water | Air has leaked out completely; usually a bladder that failed slowly | Try adding air. If it won't hold for a week, replace the tank. |
The second test takes ten seconds: rock the tank. A healthy 32-gallon Well-X-Trol has roughly 10 gallons of water sitting in the bottom and air everywhere else. You can tip it a little with one hand. A waterlogged one is full of water top to bottom, and 20-plus extra gallons of water is well over 100 extra pounds. When I was still doing service calls, that was how I found most of them before I ever pulled out a gauge. If it feels like a boat anchor, it's done.
Aidan on how a pressure tank works, the signs one is failing, and what "waterlogged" actually means. The failure-signs section starts at 3:03.
Is It the Tank, the Pump, or the Switch?
The tank does not make pressure. The pump makes pressure, the switch tells the pump when to run, and the tank stores a cushion of it so the pump doesn't have to start every time someone rinses a glass. When the symptom is "pressure is wrong," any of the three can be at fault, and people replace the tank first because it's the biggest thing in the room.
Stand at the tank with the pump on and a faucet running, and watch the gauge through one full cycle. Three patterns cover almost every call (a stuck gauge, a bleeding check valve, or weak pressure at one fixture are in the table above):
| What the gauge does | Points to | Why |
|---|---|---|
| Drops from 50 to 30 in a few seconds, pump starts, climbs back to 50 in a few seconds, pump stops, repeats every 10 to 30 seconds while water runs | Tank | There's no air cushion left. Every ounce you use has to come straight from the pump. |
| Drops to 30, pump starts, and the pump then stays on the whole time the faucet runs, shutting off at 50 only after you close it | Nothing is wrong | That is exactly how a bladder tank is supposed to behave. See the next section. |
| Pump starts at 25 and stops at 45 (or never quite reaches the high number) on a switch labeled 30/50 | Pump or switch | I had a caller this July whose 2012 tank did this for a year before the bladder went. A tired pump can't build the last few PSI; a worn switch trips early. |
One number to write down before you call anyone: what the gauge reads with the pump off and every faucet closed, after the pump has just shut off. On a 30/50 system that should be 50. If it's 45, that's a pump or switch conversation. If it's 50 and the pump still cycles like a metronome, that's a tank conversation.
Can't tell if it's the tank or the pump?
Text me your two gauge readings and a photo of the tank tee. I'll tell you if it's a $2 valve core, a $25 switch, or a new tank.
8 AM to 5 PM Eastern, seven days a week. A real person, not a call center.Number copied. Text it from your phone: 443-277-2204.
What "Normal" Looks Like (Two Things People Get Wrong)
A pump that starts every time you flush is normal. A pump that starts and stops every few seconds while water is running is not. Those two beliefs, mixed up, send more people shopping for a tank they don't need than anything else.
"The pump turns on every time I flush. Something's wrong."
Nothing is wrong. A Well-X-Trol WX-203 is a 32-gallon tank, but it holds about 10 gallons of usable water between the pump turning off and turning back on. That's called drawdown, and it's the same on every bladder tank of that size. A toilet uses 1.6 gallons, a shower runs 2 gallons a minute, so a couple of flushes or a few minutes of shower and the pump is going to start. That's the design. The tank was never meant to store water; it's there to stop the pump from starting for a single glass.
What matters is what happens next. Once the pump starts, it should stay running as long as water is being used, and shut off shortly after you close the faucet. If it does that, you have a healthy system.
"A bigger tank will stop the cycling."
If the tank is waterlogged, a bigger waterlogged tank cycles exactly the same. If the tank is healthy, going from a WX-203 to a WX-250 adds about 4 gallons of drawdown, which means the pump starts a little less often when you're using small amounts of water and not at all differently when you're running a shower. I tell people straight out: for most houses a bigger tank is a waste of money, and two tanks in parallel is rarely necessary in a home. Where a larger tank does earn its keep is a pump over 10 GPM (you want roughly a gallon of drawdown per GPM of pump output) or a house that added bathrooms, irrigation, or a backwashing filter since the original tank went in. See the sizing guide for the actual math.
Problem 1: Waterlogged Pressure Tank
A waterlogged tank is one where the bladder (Amtrol calls it a diaphragm; same thing) has torn, so water has pushed into the air chamber on top and there is no compressed air left to push water out to the house. The pump has to do all of that work itself, which is why it starts and stops every few seconds.
Symptoms
- Pump cycles on and off every 10 to 30 seconds any time water is running. This is the one that gets people to call.
- Faucets spit, pulse, or surge, especially when the pump kicks on.
- Rapid clicking from the pressure switch next to the tank.
- The tank is very heavy. You can't rock it.
- Knocking on it sounds the same, dull and full, near the top as near the bottom. A healthy tank rings hollow on top.
- Water comes out of the air valve when you press a gauge on it. This one is conclusive.
Why it happens
- Age. Butyl rubber flexes tens of thousands of times over 10 to 15 years and eventually cracks.
- Acidic water. This is the one people don't expect. Low pH attacks rubber and rusts the steel fitting under the tank. About 1 in 12 of the well tests our customers have run through us came back acidic (below pH 6.5), a few of them badly. If yours is acidic, an acid neutralizer downstream of the tank protects the house, but the tank itself sees the raw water, which is why Amtrol put a stainless fitting under the Pro Series.
- Sediment and grit abrading the bladder from the water side.
- Wrong pre-charge. Air set too high or a switch cranked past the tank's rating overstretches the bladder every cycle.
- Defects. Rare, but I've seen a bladder go in four months. That's what the 7-year warranty is for.
⚠️ The pump is the expensive part
Pump manufacturers rate submersibles for roughly 6 to 8 starts per hour. A waterlogged tank can push that past 100. Each start dumps inrush current into the motor windings, and with no rest between starts they never cool. A replacement submersible pump runs $1,000 to $2,000, and pulling and resetting it can add another $1,000 to $2,000 in labor. A new tank is a fraction of that bill. Whenever a customer says "I'll deal with the tank next spring," this is the math I show them.
Can you keep using the water while you wait for the new tank?
Yes, within reason. A customer called on July 2nd with a WX-203 from 2012 that had gone waterlogged right before the holiday weekend and asked if he needed to shut the house down. My answer was the same one I'd give you: as long as you have pressure, use the water normally for a few days. Don't run irrigation or fill a pool off it, because that's an hour of nonstop cycling, and get the new tank on order. He ordered a 203 package, swapped it the following week, and the pump survived.
Can it be repaired?
No. The bladder is sealed inside the shell at the factory and is not a serviceable part on any modern residential tank, including the Well-X-Trol. There is no such thing as rebuilding a bladder tank; a "rebuild" is a new tank. If you have an old galvanized tank with no bladder at all, that is a different situation, and it's covered next.
Problem 1b: The Old Galvanized Tank With No Bladder
If your tank is a plain galvanized steel cylinder with no air valve on top, often with a small brass float valve on the side (an air volume control), it doesn't have a bladder. Water and air sit in the same chamber, and the air slowly dissolves into the water. When enough of it is gone, the tank waterlogs and the pump short cycles. The word "waterlogged" comes from these tanks.
On a galvanized tank, waterlogging is fixable, at least for a while:
- Turn the pump off.
- Open the drain valve at the bottom and a faucet in the house, and let the tank drain completely. Leave both open so air can enter.
- Close the drain and the faucet, turn the pump back on, and let it fill. The tank refills with a fresh air pocket on top.
- If the tank has an air volume control, check that the float and the little bleeder line to the pump are not clogged; that's the part that's supposed to keep the air topped up automatically.
Expect to repeat this every few months. When it becomes every few weeks, or when the tank starts weeping rust at the seams, replace it with a bladder tank. A bladder tank of the same footprint gives you more usable water, needs no periodic draining, and the pump runs less.
Problem 2: Short Cycling
Short cycling is the pump turning on and off every 10 to 30 seconds while water is being used. It is a symptom, not a diagnosis, and there are four causes. Work through them in this order because each one is cheaper to check than the next.
1. Waterlogged tank
2. Low air pre-charge
3. Pressure switch
4. Undersized tank
Problem 3: Low Water Pressure
Low pressure is almost never the tank. The tank can only give back the pressure the pump put into it. Five checks, in order:
- Read the gauge with nothing running, right after the pump shuts off. It should sit at your cut-out (50 or 60). If it's stuck below that, the pump can't reach the number or the switch is shutting it off early. That is a pump or switch problem.
- Check the switch setting. Someone may have turned the big nut down. Standard residential is 30/50; 40/60 is common on newer homes and gives noticeably stronger showers.
- Check the pre-charge (pump off, tank drained). If it's way off, the tank empties strangely and the pressure swings feel bigger than they are.
- Walk the plumbing between the tank and the fixtures. A sediment cartridge that hasn't been changed in a year, a ball valve someone left half closed, or original galvanized pipe that's rusted down to a pencil-width opening will all read as "low pressure" while the tank and pump are perfect.
- Have the pump tested. If everything above is right and the pressure is still weak, the pump is losing capacity. A well tech can measure its output against the nameplate.
✅ Want more pressure? Change the switch, not the tank
Moving from a 30/50 to a 40/60 switch raises every faucet in the house by 10 PSI. You'll need to reset the tank pre-charge to 38 PSI and make sure your water heater's relief valve, any water treatment equipment, and old plumbing are fine at 60. Most are. It's a $25 part and half an hour.
When low pressure does point to the tank
If the gauge shows a good 50 with nothing running but drops to 30 the instant you open a shower, and the pump immediately starts, the tank has no cushion: either waterlogged or badly undersized. That fast collapse is the tell.
Problem 4: Tank Won't Hold Air
A tank that won't hold its air pre-charge has one of two leaks: a $2 valve core or a pinhole in the bladder. You checked the pre-charge, it was low, you brought it up to 28, and three weeks later it's low again. Before you condemn the tank, rule out the cheapest part on it.
- With the tank pressurized, dab soapy water on the air valve. If it bubbles, the valve core is leaking. A replacement core is $2 at any auto parts store and takes 30 seconds with a core tool.
- If the valve is dry, the air is going through the bladder into the water. Recharge to the correct number, write the date and reading on the tank, and recheck in one week. Losing more than a couple of PSI in a week means the bladder has a pinhole.
⚠️ A slow bladder leak only goes one direction
It never seals itself. Every few months becomes every few weeks becomes every few days, and the whole time the pump is short cycling a little more. By the time you're topping it up weekly, the tank has been quietly wearing the pump for months. Replace it at the "every few weeks" stage, not the "every few days" stage.
Problem 5: Fluctuating Pressure, Sweating, and Leaks
Fluctuating pressure is usually a partially waterlogged tank, a failing check valve, or two pieces of treatment equipment backwashing at the same time. It confuses people because it has the most possible causes. Here is how I sort them:
| Cause | What you notice | How to confirm |
|---|---|---|
| Partially waterlogged tank | Pressure swings between decent and weak; pump cycles more than it used to | Pre-charge check and the rock test |
| Failing check valve | Gauge drifts down after the pump stops, pump starts on its own overnight | Watch the gauge for 10 minutes with everything closed |
| Clogged switch nipple | Pump trips at odd, changing pressures | Pull the switch, look for scale or iron sludge in the tube |
| Treatment equipment backwashing | Fluctuation at the same time every day or night, usually 2 AM | Check the regeneration times on your softener, iron filter and neutralizer |
| Too many fixtures at once | Only when the shower, dishwasher and washer are all running | Normal on a small tank or a low-GPM pump |
The 2 AM backwash pile-up
If you have an iron filter, a neutralizer and a softener and they all regenerate at 2 AM, they fight each other for flow and the pump cycles hard for an hour. Stagger them: one at 1 AM, one at 3, one at 5. This costs nothing and I fix it over the phone a few times a month.
"My tank is sweating"
Condensation on the outside of a steel tank in a humid basement is normal in summer. Well water comes in at 50 to 55 degrees and the tank is a big cold surface. It is not a leak unless it's wet at a seam or the fitting when the rest of the tank is dry. Wipe it dry, wait an hour, and see where the moisture comes back first.
"My tank is leaking from the bottom"
Almost always the steel connection under the tank, not the tank itself. On older tanks that fitting is the first thing acidic water eats through, and by the time it drips, the threads are gone. That's a tank replacement, and it's the reason the current Pro Series tanks have a stainless steel fitting there instead of steel.
Constant pressure systems
If the fluctuation drives you crazy and both the pump and the tank are due, a variable-speed constant pressure system holds one steady number regardless of how many fixtures are open. It's a bigger job than a tank swap and a different conversation; see constant pressure well systems.
Replace vs. Repair
Honest version from the service years: most tank problems end in a new tank, because the tank has almost no serviceable parts. But not every problem, and not today.
✅ Fix it, don't replace it
- Low pre-charge that holds after you add air: free
- Leaking air valve core: $2 to $5
- Bad pressure switch: $15 to $30
- Clogged switch nipple or gauge port: under $10
- Old galvanized tank that waterlogged: drain and refill, free
⚠️ Replace it
- Water from the air valve. No repair exists.
- Won't hold air for more than a few weeks. Progressive failure.
- Rust holes, weeping at a seam or the bottom fitting, a swollen shell.
- Over 15 years old with any symptom. The bladder is on borrowed time either way.
- Galvanized tank that needs draining more than every couple of months.
| Tank age | Symptoms | What I'd do |
|---|---|---|
| 0 to 7 years | Any | Diagnose carefully; a Pro Series tank is still under warranty and a bad bladder gets exchanged |
| 7 to 10 years | Minor | Recharge, mark the date, monitor. Budget for a tank in the next few years. |
| 10 to 15 years | Any | Replace. Repairs buy months, not years. |
| 15+ years | Even none | Replace when you're doing other work on the system. A planned swap on a Saturday beats an emergency one on a holiday weekend. |
Replacing the Tank: What to Buy and What Comes in the Box
Replace the switch, gauge and relief valve along with the tank, and size the new tank to the pump rather than the house. Those are the two things I say on every one of these calls.
Replace everything on the tee, not just the tank. The pressure switch, gauge, relief valve and boiler drain are all the same age as the tank and have all been living in the same water. Our Well-X-Trol packages ship with a new tank tee, switch, gauge and relief valve in the box for that reason. Reusing a 12-year-old switch on a new tank is how you end up doing the job twice.
Buy the size the pump needs, not the biggest one that fits. The 32-gallon WX-203 is what we installed in the large majority of houses when we were still doing installs, and it's still the right answer for most 1- to 3-bathroom homes with a pump under 10 GPM.
| Model | Total volume | Usable drawdown at 30/50 (Amtrol spec) | Best for | Price, shipped |
|---|---|---|---|---|
| WX-202 Pro Series | 20 gal | 6.2 gal | 1 bathroom, cabins, pumps under 7 GPM | $1,095 |
| WX-203 Pro Series | 32 gal | 9.9 gal | Most 1 to 3 bathroom homes; our most common replacement | $1,295 |
| WX-205 Pro Series | 34 gal, short and wide | 10.5 gal | Same duty as the 203 where height is limited (crawl spaces, low pits) | $1,695 |
| WX-250 Pro Series | 44 gal | 13.6 gal | Pumps over 10 GPM, 4+ bathrooms, irrigation on the well | $2,195 |
Steel Well-X-Trol tanks are what most plumbers have installed for 40 years and what we recommend. Fiberglass composite tanks (WellMate is the common brand) won't rust on the outside and weigh about half as much, which matters in a damp crawl space or up a tight stairway; they cost about the same. Every tank we sell ships free to the lower 48 with a 7-year manufacturer warranty that we handle for you.
Did the old tank fail young? Test the water before the new one goes in
Low pH and grit are what kill bladders early. One certified lab test, mailed to you, run by an accredited lab, shows the pH, iron, hardness, and sediment so the next tank lasts.
53 contaminants. Results reviewed by Aidan, in plain English.What the swap actually involves
Pump off, drain the system, unscrew the old tank from the tee (or cut the pipe and re-plumb the new tee), set the new tank, set the pre-charge with the tank empty (Amtrol ships every Well-X-Trol at 38 PSI, so let air out to 28 if you run a 30/50 switch), wire the switch, power up, check for leaks. Two hours for a handy homeowner with a pipe wrench and a compressor, less for a plumber. If you're paying a plumber, the labor is typically $200 to $500 on top of the tank for a straightforward swap, which is where the $2,000 to $3,000 quotes people post about online come from. Most of that is the tank marked up and a service call; the work itself is not complicated.
Frequently Asked Questions
How do you fix a waterlogged pressure tank?
If it's a bladder tank (any tank with a tire-style air valve on top), you don't. The bladder is sealed inside the shell and cannot be replaced; the fix is a new tank. If it's an old galvanized tank with no bladder, turn the pump off, drain the tank completely with a faucet open so air can enter, close everything and let it refill. That restores the air pocket for a few months.
How do I tell if my well pressure tank is waterlogged?
Pump off, drain the tank through a faucet, press a tire gauge on the air valve on top. Water coming out means the bladder has torn and the tank is waterlogged. A second check: try to rock the tank. A healthy 32-gallon tank tips easily; a waterlogged one carries 100-plus pounds of extra water and won't budge.
Is it normal for the pump to turn on every time I flush the toilet?
Yes. A standard WX-203 holds about 10 gallons of usable water; a couple of flushes or a few minutes of shower will start the pump. That's how it's designed. The problem sign is the pump turning on and off repeatedly while water is running, not the pump starting once and staying on.
How often should a well pump cycle on and off?
Pump makers rate submersibles for about 6 to 8 starts per hour. Under normal use the pump should start, run for at least a minute or two, and rest. On and off every 10 to 30 seconds while water runs is short cycling, and it is damaging the pump with every start.
Can I keep using my water if the tank is waterlogged?
For a few days, yes, as long as you still have pressure. Avoid long draws like irrigation or filling a tub, since every minute of running water is a minute of the pump cycling. Get the replacement on order; the risk you're carrying is the pump, not the water.
What should the air pressure be in my well pressure tank?
2 PSI below the pressure switch cut-in, checked with the pump off and the tank drained. 28 PSI for a 30/50 switch, 38 PSI for a 40/60. Checking it with the system pressurized gives you the water pressure, not the pre-charge.
What causes a pressure tank to lose air?
Either the air valve core is leaking (soapy water on the valve will bubble; a $2 core fixes it) or the bladder has a pinhole and air is migrating into the water side. If the valve is dry and the pre-charge drops more than a couple of PSI in a week, it's the bladder, and the tank needs replacing.
Why is my pressure tank sweating?
Condensation. Well water is 50 to 55 degrees and the steel shell is a big cold surface in a humid basement. It's normal in summer and not a leak. A leak shows up wet at one spot, usually the bottom fitting or a seam, while the rest of the tank is dry.
How do you reset a pressure tank?
There's nothing electronic to reset. "Resetting" means restoring the air pre-charge: pump off, drain to zero, add air to 28 or 38 PSI, power back on. If the pump won't restart at all, the pressure switch may have tripped on its low-pressure cutoff; hold the lever on the side of the switch up until pressure builds past 30.
How long do well pressure tanks last?
10 to 15 years is typical for a quality bladder tank; we've seen Well-X-Trols go 20 and more on good water. Acidic water, heavy sediment, or a badly sized tank that cycles constantly shortens that. The Pro Series carries a 7-year warranty.
What's the difference between a bladder and a diaphragm tank?
Functionally nothing that matters to you. A bladder is a replaceable-in-theory bag; a diaphragm is a sheet fixed to the shell. Both separate the air from the water, and in residential tanks including the Well-X-Trol, neither is serviceable once it fails.
Do I need a plumber to replace a pressure tank?
Not necessarily. The tank connects to the tee with a standard threaded fitting, and the switch wiring is two wires plus ground. If you're comfortable turning off a breaker and using a pipe wrench, it's a two-hour job. The hardest part is physically moving a 45-pound tank in and out of a tight mechanical room.
Aidan Walsh
Aidan Walsh has spent 32 years in residential water treatment, the first stretch of it installing and servicing well systems before Mid Atlantic Water became an online supplier. Mid Atlantic Water is a family company; every recommendation on this site is based on what actually failed in the field and what fixed it. If you have a question this page did not answer, call or text him.
Aidan answers calls and texts 8 AM to 5 PM Eastern, every day.Number copied. Text it from your phone: 443-277-2204.