Accumulator Tanks
What Are Accumulator Tanks?
If you've ever been annoyed by the constant click-and-hum of a water pump cycling on and off every time you turn on a faucet aboard your boat or RV, an accumulator tank may be exactly what your plumbing system needs. These compact devices act as a pressurized buffer between your water pump and the rest of your onboard plumbing, smoothing out delivery and dramatically reducing the frequency with which your pump has to run.
At the heart of every accumulator tank is a flexible rubber bladder or diaphragm housed inside a sealed chamber. When your pump runs, it fills the bladder with water, simultaneously compressing the air on the other side. When you open a tap, that stored pressure pushes water through your lines — no pump required — until the system pressure drops enough to trigger the pump again. The result is a noticeably smoother, quieter flow at every fixture aboard.
Why Accumulator Tanks Matter for RV & Marine Plumbing
Rapid pump cycling — sometimes called short cycling — is more than just a nuisance. Every unnecessary start and stop adds wear to your pump's motor, diaphragm, and pressure switch. Over time, this can shorten the pump's service life considerably. An accumulator tank reduces those starts and stops, meaning less wear and tear and a longer-lasting pump.
Beyond pump protection, accumulator tanks offer real comfort benefits. Pressure stabilization means that when multiple outlets are open simultaneously — say, a shower and a galley faucet — you won't experience dramatic swings in flow or temperature. You can also draw a small amount of water, like rinsing your hands or filling a glass, without the pump kicking on at all, which is especially welcome late at night when fellow passengers are sleeping.
Accumulator tanks are also a smart addition for battery-powered systems. By reducing total pump run time, they help conserve precious amp-hours — a meaningful advantage for off-grid boaters and RV owners relying on solar or limited shore power.
What to Look for When Choosing an Accumulator Tank
- Size and capacity: Larger tanks reduce pump cycling more effectively and prolong motor and pressure switch life. Choose the largest tank that fits your available space.
- Operating pressure: Make sure the tank's maximum working pressure rating matches or exceeds your system's pump output pressure.
- Pre-charge pressure: The tank's air charge should be set to match your pump's cut-in (turn-on) pressure for optimal performance.
- Construction material: Options include plastic, painted steel, and stainless steel. Consider your environment — saltwater exposure demands corrosion-resistant materials.
- Mounting flexibility: Many tanks can be mounted in any orientation, making installation easier in tight bilge or cabinet spaces.
Top Accumulator Tank Brands
Groco is one of the most trusted names in marine plumbing, and their PST Series pressure storage tanks are a go-to choice for serious boaters. Groco's tanks feature a rubber bladder that separates the air charge from system water, delivering smooth pressure, even shower temperature mixing, and reduced pump cycling across a wide range of sizes.
Johnson Pumps brings decades of marine engineering expertise to their accumulator tank lineup. Designed as a natural complement to their popular Aqua Jet water pressure systems, Johnson Pumps accumulator tanks are engineered for quiet operation and reliable performance in both leisure and commercial vessel applications.
Devilbiss offers accumulator tank solutions that round out a well-stocked selection for RV and marine plumbing needs, providing additional options for those seeking reliable pressure management components for their onboard water systems.