GROCO Pressure Storage Accumulator Tank — Up to 100 PSI, Fresh or Salt Water (PST-1)
Free returns on all eligible orders
You have 30 days to request a return. All sale items are final sale.
GROCO Pressure Storage Accumulator Tank — Up to 100 PSI
Smoother water pressure, fewer pump cycles, and better shower temperature control — all from a single tank. The GROCO PST-1 is a pneumatic accumulator tank that stores pressurized water between pump cycles, so your pump doesn’t have to kick on every time someone opens a tap. A rubber bladder inside the tank separates the air charge from the water, preventing waterlogging and maintaining consistent pressure delivery. The result is noticeably smoother flow at the tap, more even hot/cold temperature mixing in showers, and significantly reduced pump wear from constant short-cycling. Mounts in any position, anywhere in the cold water plumbing after the pump, and works with both fresh and salt water systems up to 100 PSI.
Key Features
- Pneumatic pressure storage — stores pressurized water to reduce pump cycling and extend pump life
- Rubber bladder separates air charge from system water — prevents waterlogging
- Delivers smooth, consistent pressure at the tap — eliminates the pulsing common with diaphragm pumps
- Improves hot/cold temperature mixing in showers by stabilizing pressure
- Mounts in any position — flexible installation anywhere in the cold water plumbing after the pump
- Compatible with fresh and salt water systems
- Operating pressure up to 100 PSI
- Mounting hardware included
Compatible Applications
- Any 12V or AC marine freshwater pressure pump system
- Installations where pump short-cycling is a problem
- Shower systems where uneven pressure causes temperature fluctuation
- Fresh and salt water plumbing systems up to 100 PSI
- Cold water plumbing runs downstream of the pressure pump
Parts Desk Insights
An accumulator tank is one of the most impactful upgrades you can add to an existing freshwater pressure system — it makes the water feel more like a household supply and dramatically reduces how often the pump runs, which extends pump life significantly. The PST-1 is GROCO’s full-size pressure storage tank, best suited for larger boats or systems where maximum pressure storage capacity is the priority. For smaller installations or tighter spaces, the Jabsco 33 oz Pressurized Accumulator Tank and the Mini Accumulator Tank are compact alternatives. Compatible freshwater pumps in the catalog include the SHURflo Aqua King II 4.0 GPM, SHURflo Aqua King II 3.0 GPM, and SHURflo Aqua King II 2.0 GPM.
Part Number: PST-1 | Max Pressure: 100 PSI | Compatible With: Fresh & Salt Water | Includes: Mounting Hardware
Shipping information
In-stock and OEM parts: ship same or next business day.
Locally warehoused items: ship within 1-3 business days.
Special-order items: timeline confirmed after order.
Returns & warranty
Returns & Satisfaction Guarantee
We stand firmly behind the quality of every product we sell. Your confidence matters to us — and we back it with a straightforward 30-Day Satisfaction Guarantee.
If you are not fully satisfied, you may request a return within 30 days of delivery. All returns must receive pre-approval prior to being sent back. Unauthorized returns will not be accepted.
To qualify for a return:
Item must be in new, unused condition
Product must be in its original packaging
All parts, components, hardware, manuals, and accessories must be included
Packaging must be undamaged and suitable for resale
Important:
Electronics are strictly inspected. No returns on open-box electronics. Exceptions may apply only with prior written approval. Any electronic unit that has been installed, powered, activated, or altered may not be eligible for return.
We are serious about product integrity — and equally serious about taking care of our customers. If there is ever a product issue, contact us immediately so we can make it right.
For return authorization, please contact our support team before shipping anything back.