Understanding how your well pressure tank works and checking it are essential to maintain your water pressure.
This well tank pressure guide with tips and how to check your tank’s pressure can help you keep the tank working correctly.
How Do Pressure Tanks Work?
Pressure tanks use air pressure to push water from the tank into your home when you turn on a faucet.
A pump fills the tank with well water until the remaining air compresses enough to reach a specified pressure, measured as pounds per square inch (psi). When the pressure inside the tank reaches the psi the tank is set to hold, the water stops.
When you open a faucet, the pressure in the tank pushes water through the pipes. The pressure drops, and when it hits a specific psi, the pump comes on and fills the tank again.
The maximum pressure in a tank is usually 40 to 60 psi, so water stops flowing into the tank when the air compression hits that level. Water pumps in again when the pressure drops to approximately 20 to 40 psi.
How to Check Water Tank Pressure
You’ll need a dial or digital pressure gauge to check your water tank pressure.
- Turn off the power at the breaker to disconnect the electricity from the tank.
- Open a faucet to drain the tank completely. The air regulator on the tank will show 0 psi when it’s empty.
- Find the air valve, known as the Schrader valve. This valve is usually on the top, covered with a silicone or rubber cap like the valve stem on a tire.
- Remove the cap, and unscrew the metal valve cap.
- Use your pressure gauge by pressing it onto the valve to see its reading.
What Psi Should My Well Tank Be?
The psi reading of your tank should be 2-3 psi below the tank’s cut-on psi setting. The cut-on psi is the pressure level in the tank that triggers the pump to pull water from the well into the tank.
If you don’t know the cut-on setting, look for the tank’s pressure switch and remove the cover. The inside of the cover has a specifications sticker showing the cut-on and cut-off pressure.
The lower number is the cut-on pressure that triggers the pump, while the higher number is the cut-off pressure that stops the water flow. For instance, a tank that says 20-40 has a cut-on psi of 20 and a cut-off psi of 40.
When you check your tank’s pressure after turning it off and draining it, its psi should read 2-3 psi below the cut-on number. If a tank’s cut-on psi is 30, the pressure while the tank is off and empty should read no more than 28 psi.
Is 70 psi Too Much Water Pressure?
Water pressure of 70 psi is probably not too much pressure unless you have old pipes in your home. Pressure higher than 70 risks straining the plumbing and damaging the system.
It’s worth bearing in mind that 70 psi drains the tank faster and gives the pump motor less resting time, which will wear it out more quickly. You’ll also use more water with higher psi.
Is 100 psi Water Pressure Too High?
Water pressure of 100 psi can seriously damage your home’s plumbing. Appliances that use water like dishwashers and washing machines are at risk of damage, too.
Is 120 psi Too High for Water Pressure?
Water pressure of 120 psi is too high and will cause faucet drips, pipe leaks, and damage to wet appliances. That much psi will strain the entire plumbing system of your home.
How to Change Pressure Tank Settings
To change the settings of your pressure tank, disconnect the power supply for safety by turning it off at the breaker.
You’ll need a ruler, tape measure, or way to measure fractions of an inch (or millimeters) and a ⅜-inch socket (unless the nut on your pressure switch is a different size).
You’ll see two rods with springs around them and nuts at the top on the pressure switch. The large one sets the cut-in psi level.
The smaller rod sets the differential between the cut-on and cut-off psi. This nut usually keeps the levels 20 psi apart. Don’t adjust this level.
On the larger spring, measure from the top of that bolt down to the first exposed thread above the nut on top. If you lose track of how many turns or adjustments you’ve made, you can reset it to this length and start over.
To change the tank’s settings:
- Turn the nut counterclockwise to decrease the cut-in psi level.
- Turn the nut clockwise to increase the cut-in psi level.
- Generally, one full rotation of the nut equals a change of 2-3 psi.
- The cut-off pressure will increase (or decrease) by the same amount, so they’ll remain 20 psi apart unless your tank has unique settings.
For example, one full turn counterclockwise on a tank with a cut-on pressure of 30 would lower the setting to 27 or 28 instead.
Three full turns clockwise on a tank with a cut-on level of 40 psi will increase it by 8-9 psi to 48 or 49 psi. This change also increases the cut-off pressure by 8-9 psi.
What Causes a Well Pressure Tank to Lose Pressure?
Your well pressure tank can lose pressure for a few different reasons.
If you use a lot of water and the tank doesn’t have time to refill, the pressure will drop. You might have a pump that’s too small to keep up with the amount of water you use if it happens often.
A leak in the tank or any of its valves will cause the tank to lose pressure, and a ruptured bladder in a bladder tank system will cause it, too.
Sometimes a dirty supply pipe coming from the tank will cause the water pressure in the home to drop, though the tank pressure is normal.
What Happens if Well Pressure Tank is Too Low?
If your well pressure tank pressure setting is too low, water will come through your pipes more slowly with less pressure behind it.
Appliances that use water will take a long time to fill up, and the water coming from faucets, taps, and showerheads will come out slower, sometimes at a trickle.
Adjusting the cut-in psi of the tank will also raise the pressure in the tank and provide higher water pressure into your home.
A tank that continually loses pressure could be from a ruptured or leaking bladder in a bladder pressure tank because it will stretch too far as too much water enters the tank. Pipe leaks can also reduce the pressure.
What Happens if Well Pressure Tank is Too High?
If the pressure in your well tank is too high, it can cause the pump to cycle on and off rapidly. The high pressure can rupture valves like the Schrader valve.
When you measure the pressure in the tank while it’s off and drained, if the pressure is higher than 2-3 psi below the cut-in psi level, you should bleed the tank by letting air escape until the pressure lowers.
Press the pin in the center of the Schrader valve to release air for one to two seconds. Measure again, and repeat until the pressure is at the right level.
How Do I Know if My Well Pressure Tank Is Bad?
Some commons signs of a pressure tank that’s going bad are:
- A water pump that cycles constantly or erratically, often shown through a high electricity bill
- Pressure fluctuating up and down on the pressure valve attached to the tank
- Air sputtering from faucets when you turn them on
- A drop in water pressure or no pressure
- Water that comes out too hot because of air in the cold water supply
- Clicking sounds that indicate the tank might be full of water, known as a waterlogged tank
- Water spurting from the air valve when you press the pin
- Obvious leaks from the tank
How Do You Clean Pressure Tank?
To clean your water pressure tank, follow this well tank pressure guide. You’ll learn tips and how to check the tank for sediment so you can clean it properly.
- Turn the power off at the breaker.
- Attach a garden hose to the spigot on the bottom of the tank.
- Put the other end of the house out a door to drain outside or into a large bucket, then open the valve to drain the tank.
- Carefully use pliers to remove the air regulator on top of the tank that shows the pressure inside the tank.
- Unscrew the access hatch on top of the tank and remove it.
- Wipe out the inside of the tank and remove sediment or particles at the bottom of the tank.
- Use steel wool to scrub any sediment deposits stuck to the tank.
- Screw the hatch into place, and replace the air regulator.
- Remove the hose and close the drain valve, then turn the breaker on to let the clean tank fill.
