GROCO Pressure Storage Tank - 4.3 Gallon Drawdown

The GROCO Pressure Storage Tank with 4.3 gallon drawdown capacity (PST-4 model) is a pneumatic accumulator designed to stabilize water pressure delivery in marine and RV plumbing systems. By separating the air charge from system water using an internal rubber bladder, this pressure storage tank eliminates water hammer, reduces pump cycling, and maintains consistent pressure throughout cold water lines—delivering the smooth, even shower temperature and pressure that users depend on in mission-critical freshwater and saltwater applications.

The PST-4 functions by matching a pre-charged air pressure to your pump's cut-on pressure setting, creating a cushioning effect that absorbs pressure spikes from pump activation. The 4.3 gallon usable drawdown volume allows the system to supply water momentarily from stored pressure before the pump cycles back on, reducing electrical load and extending pump service life. The tank's rubber bladder isolates air from water, preventing air absorption into the system—a critical distinction from older diaphragm-style tanks that gradually waterlog over time. Mount position flexibility means the GROCO PST-4 can be installed anywhere in the cold water line downstream of the pump, whether horizontally, vertically, or at an angle, accommodating tight spaces in engine rooms, lazarettes, or under-sink installations.

Yacht owners, liveaboards, and RV operators facing salt-water corrosion challenges will appreciate that GROCO pressure storage tanks are rated for both fresh and salt water service. This tank is engineered for marine systems where reliability and corrosion resistance directly impact extended cruising comfort. The PST-4 is commonly paired with smaller 12V or 24V demand pumps found on cruising sailboats, trawlers, and expedition vehicles where minimizing battery draw and reducing noise from frequent pump activation is essential to the cruising lifestyle.