The pressure on a well pump system is not a single static number but rather a range within which the system operates. This range is controlled by a pressure switch that tells the pump when to turn on and off.
Based on standard configurations, the standard pressure required for well tanks should be around 30/50. This means the pump typically turns on when the system pressure drops to 30 psi (pounds per square inch) and turns off when it reaches 50 psi.
Understanding Well System Pressure
Well pump systems utilize a pressure tank to store water and maintain pressure in your home's plumbing. The pump fills the tank until the upper pressure limit is reached, then shuts off. As you use water, the pressure in the tank drops until it hits the lower limit, signaling the pump to turn back on.
Key Pressure Points
Several pressure points are crucial in a well pump system:
- Cut-In Pressure: The lower limit at which the pressure switch activates the pump. A common standard is 30 psi.
- Cut-Out Pressure: The upper limit at which the pressure switch deactivates the pump. A common standard is 50 psi.
- Tank Pre-Charge Pressure: The air pressure inside the pressure tank's bladder when the tank is empty of water. This is typically set slightly below the cut-in pressure.
| Pressure Type | Typical Value (Standard) | Role in the System |
|---|---|---|
| Cut-In Pressure | 30 psi | Pump turns ON at this pressure |
| Cut-Out Pressure | 50 psi | Pump turns OFF at this pressure |
| Tank Pre-Charge | Around 28 psi | Air pressure in empty tank, supports cut-in pressure |
As noted in the reference, it's common to see the pressure at 28 psi. This 28 psi likely refers to the pre-charge pressure of the well tank bladder, which should be set approximately 2 psi below the cut-in pressure (like 30 psi).
How Pressure Tanks and Bladders Work
Well tank bladders help keep your tank functioning properly. The bladder separates a pocket of air (under pressure) from the water entering the tank.
- When the pump turns on, it pushes water into the tank, compressing the air in the bladder.
- This compressed air is what maintains pressure in your home's pipes when the pump is off.
- Setting the correct pre-charge pressure (like the common 28 psi noted) ensures the bladder functions effectively with the 30/50 standard pressure range.
This mechanism is vital because it is another safeguard as to why well pumps can turn on and off between each use without unnecessarily wearing out the motor. The pressure tank stores enough water under pressure so the pump doesn't need to short-cycle every time you open a faucet.
In summary, while the system cycles between pressures like 30 and 50 psi, the critical tank pre-charge pressure, essential for efficient operation, is often set around 28 psi.
