Understand your pressure tank before replacing it.
A correctly matched tank helps limit pump cycling. The important number is usable drawdown between pressure-switch settings — not the tank’s advertised gallon capacity alone.
What the main components do
Stores usable water under pressure
In a pre-charged pressure tank, compressed air drives water out between the pump’s cut-out and cut-in pressure settings.
Starts and stops the pump
Common switch ranges include 30/50 and 40/60 psi. The correct settings depend on the system design and component ratings.
Shows system pressure
A readable, functioning pressure gauge helps distinguish pressure loss, slow recovery and abnormal cycling patterns.
Tank size is a system calculation.
A simple starting relationship is required drawdown (gallons) = pump flow (GPM) × target minimum runtime (minutes). The actual tank capacity needed depends on its drawdown rating at the specific pressure range.
If the design requires 10 GPM for one minute of minimum runtime, the target usable drawdown is 10 gallons. That does not mean a 10-gallon nominal tank is sufficient.
Verify the pressure range, tank manufacturer’s drawdown table and pump guidance before selecting a size.