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Marine Water or Waste Holding Tanks - 11 to 25 Gallons

The Best Marine Water Tanks & Waste Holding Tanks for Boaters
Salt. Spray. Motion. Pressure. Plumbing a boat or marine vehicle isn’t just about finding a tank that fits — it’s about choosing one that can handle life at sea. But those same elements—corrosive salt, relentless UV rays, and the constant pounding stress from waves—are absolutely brutal on your boat's equipment. This is especially true for your holding tanks. A thin, brittle, or poorly-made tank isn't just an inconvenience; it's a ticking time bomb for a catastrophic leak or a smell you can't get rid of....

That’s exactly why these tanks exist. This is our premier line of marine water and waste holding tanks, engineered to pull double duty and built to survive. Whether you need a safe, robust marine water tank for your galley or a bulletproof marine waste holding tank for black water, this is your 'buy it once' solution. Built from heavy-duty, rotationally molded, corrosion-proof polyethylene, these plastic boat tanks with sizes sizes from 3 gallons to 260 gallons are designed to fit your hull, withstand the sea, and give you one less thing to worry about. With blank tank options, pre-installed fittings, and fully customizable configurations, you’re in control of your system — down to the last thread.

Key Applications of Marine Fresh Water & Waste Holding Tanks

These tanks are the foundation of a reliable marine plumbing system, giving you the flexibility to build it right for any application.

Trust Your Water Supply
Trust Your Water Supply

When you're miles from shore, you need a safe source. Our boat water tanks are manufactured from FDA-approved, food-grade, BPA-free resin, ensuring your water is 100% potable, safe, and taste-free.

Built for All Onboard Needs
Built for All Onboard Needs

These tanks are the perfect potable water tank for boat systems. They are built to reliably feed your galley water systems, supply deck rinse stations, and serve as durable potable water reserves on day or offshore boats.

Lock in Odors for Good
Lock in Odors for Good

A boat holding tank for waste cannot fail. Our marine waste tanks feature a seamless, thick wall marine holding tank construction (up to 3/8-inch thick) that is impermeable to waste, permanently locking in odors and preventing leaks.

Meet All Waste Compliance Needs
Meet All Waste Compliance Needs

Engineered as the ultimate marine black water tank, these versatile tanks are also perfect for galley or shower grey water holding. They are designed to meet the rigorous standards of boats requiring Coast Guard-compliant waste systems, giving you total peace of mind.

Why Choose Tank Depot for your Marine Fresh Water Tanks and Marine Waste Holding Tanks

When you're outfitting your vessel, you need two things: a product that can survive the sea and a partner who understands the complexity of a boat. Here’s why we are the top choice for boaters who demand reliability.

Unrivaled Selection
Unmatched Durability

Our tanks are rotationally molded into a single, seamless piece. This process, combined with heavy-duty polyethylene construction (up to 3/8" thick), means there are no weak points to leak, crack, or fail. They are 100% corrosion-proof, won't rust like metal, and are impervious to the stresses of salt, waste, and constant hull vibration.

Installation Flexibility
Installation Flexibility

We know "one-size-fits-all" doesn't work on a boat. Many of our tanks ship "blank," allowing you to drill and place fittings to match your exact plumbing lines. Need something more? Our "Build Your Own Tank" service makes you the designer.

The Right Fit for Your Hull
The Right Fit for Your Hull

Don't compromise on capacity. Our inventory is one of the largest available, with tanks from a compact 3 gallons to a massive 260 gallons.Our marine tanks are designed to maximize storage in the tight, irregular spaces of a hull.

Compliance and Peace of Mind
Compliance and Peace of Mind

Sail with confidence. Our Trionic marine waste holding tanks are built to meet or exceed all U.S. Coast Guard standards, including FDA 177.1520, giving you peace of mind for inspections, pump-outs, and safe operation on the water.

Expert Support
Expert Support

We understand the unique challenges of marine plumbing. Our expert team can review your drawings, help you plan your system, and ensure you get the right tank and the right fittings for your specific build, the first time.

The Complete System in One Stop
The Complete System in One Stop

A tank is just the beginning. We also stock marine and RV tank accessories, including the specific fitting kits, pump-out kits, and gauges you need to complete your installation like a pro.

Start Your System with a Marine Water & Waste Tank That’s Built for the Water — and Built to Last

From the bilge to the bow, every inch of your boat or marine vehicle serves a purpose. Your water and waste systems should be no different. At Tank Depot, we carry a full selection of marine-rated plastic holding tanks designed to make your install smoother, your system safer, and your time on the water cleaner and more reliable.

Whether you're piecing together a full marine sanitation system, upgrading an aging boat water storage tank, or starting fresh with a 50-gallon rectangular marine tank, we've got the right options to match your space, your specs, and your standards.

Not sure what size you need? Want help mapping out your fittings? Our team has helped thousands of boat owners, van lifers, and RV techs build smarter plumbing systems — and we’re here when you’re ready. Browse all options below.
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Capacity Name Diameter Length Width Height SKU Price
Buy 11 Gallon Plastic Marine and RV Water or Waste Holding Tank by Ronco Plastics for only $269.99 11 Gallons Buy 11 Gallon Plastic Marine and RV Water or Waste Holding Tank by Ronco Plastics for only $269.99 Ronco Plastics 11 Gallon Plastic Marine and RV Water or Waste Holding Tank 17 16 11 R-B375 $269.99
Buy 11 Gallon Plastic RV Water Tank by Ronco Plastics for only $391.00 11 Gallons Buy 11 Gallon Plastic RV Water Tank by Ronco Plastics for only $391.00 Ronco Plastics 11 Gallon Plastic RV Water Tank 24 15.5 8.25 R-14W $391.00
Buy 11 Gallon Plastic Marine and RV Water or Waste Holding Tank by Ronco Plastics for only $239.99 11 Gallons Buy 11 Gallon Plastic Marine and RV Water or Waste Holding Tank by Ronco Plastics for only $239.99 Ronco Plastics 11 Gallon Plastic Marine and RV Water or Waste Holding Tank 35 19.5 4.75 R-B319 $239.99
Buy 11 Gallon Plastic Marine Water or Waste Holding Tank by Ronco Plastics for only $183.00 11 Gallons Buy 11 Gallon Plastic Marine Water or Waste Holding Tank by Ronco Plastics for only $183.00 Ronco Plastics 11 Gallon Plastic Marine Water or Waste Holding Tank 15.375 13.5 13.5 R-B286 $183.00
Buy 11 Gallon Plastic RV Water Tank by Ronco Plastics for only $391.00 11 Gallons Buy 11 Gallon Plastic RV Water Tank by Ronco Plastics for only $391.00 Ronco Plastics 11 Gallon Plastic RV Water Tank 18 13 13 R-16W $391.00
Buy 12 Gallon Plastic Marine Water or Waste Holding Tank by Ronco Plastics for only $269.99 12 Gallons Buy 12 Gallon Plastic Marine Water or Waste Holding Tank by Ronco Plastics for only $269.99 Ronco Plastics 12 Gallon Plastic Marine Water or Waste Holding Tank 17.5 14 12 R-B105 $269.99
Buy 12 Gallon Plastic RV or Marine Water or Waste Holding Tank by Ronco Plastics for only $153.50 12 Gallons Buy 12 Gallon Plastic RV or Marine Water or Waste Holding Tank by Ronco Plastics for only $153.50 Ronco Plastics 12 Gallon Plastic RV or Marine Water or Waste Holding Tank 29.75 13.875 8.125 R-3W $153.50
Buy 12 Gallon Plastic Marine and RV Water or Waste Holding Tank by Ronco Plastics for only $269.99 12 Gallons Buy 12 Gallon Plastic Marine and RV Water or Waste Holding Tank by Ronco Plastics for only $269.99 Ronco Plastics 12 Gallon Plastic Marine and RV Water or Waste Holding Tank 20 12 12 R-B124 $269.99
Buy 12 Gallon Plastic Marine and RV Water or Waste Holding Tank by Ronco Plastics for only $269.99 12 Gallons Buy 12 Gallon Plastic Marine and RV Water or Waste Holding Tank by Ronco Plastics for only $269.99 Ronco Plastics 12 Gallon Plastic Marine and RV Water or Waste Holding Tank 23 11.5 11.5 R-B279 $269.99
Buy 12 Gallon Plastic Marine and RV Water or Waste Holding Tank by Ronco Plastics for only $207.00 12 Gallons Buy 12 Gallon Plastic Marine and RV Water or Waste Holding Tank by Ronco Plastics for only $207.00 Ronco Plastics 12 Gallon Plastic Marine and RV Water or Waste Holding Tank 15.5 15.25 14.75 R-B441 $207.00
Buy 12 Gallon Plastic Marine Water Tank without Fittings by Ronco Plastics for only $275.00 12 Gallons Buy 12 Gallon Plastic Marine Water Tank without Fittings by Ronco Plastics for only $275.00 Ronco Plastics 12 Gallon Plastic Marine Water Tank without Fittings 23.5 17.875 9.875 R-B199 $275.00
Buy 12 Gallon Plastic Marine Water or Waste Holding Tank by Ronco Plastics for only $220.00 12 Gallons Buy 12 Gallon Plastic Marine Water or Waste Holding Tank by Ronco Plastics for only $220.00 Ronco Plastics 12 Gallon Plastic Marine Water or Waste Holding Tank 17 17 11 R-B255 $220.00
Buy 12.5 Gallon Plastic Marine and RV Water or Waste Holding Tank by Ronco Plastics for only $269.99 12.5 Gallons Buy 12.5 Gallon Plastic Marine and RV Water or Waste Holding Tank by Ronco Plastics for only $269.99 Ronco Plastics 12.5 Gallon Plastic Marine and RV Water or Waste Holding Tank 24 13.5 10 R-B548 $269.99
Buy 13 Gallon Plastic Marine Water Tank without Fittings by Ronco Plastics for only $293.00 13 Gallons Buy 13 Gallon Plastic Marine Water Tank without Fittings by Ronco Plastics for only $293.00 Ronco Plastics 13 Gallon Plastic Marine Water Tank without Fittings 36.5 11 10 R-B436 $293.00
Buy 13 Gallon Plastic RV Water Tank by Ronco Plastics for only $391.00 13 Gallons Buy 13 Gallon Plastic RV Water Tank by Ronco Plastics for only $391.00 Ronco Plastics 13 Gallon Plastic RV Water Tank 29.75 16 7.5 R-37W $391.00
Buy 13 Gallon Plastic Marine Water or Waste Holding Tank by Ronco Plastics for only $220.00 13 Gallons Buy 13 Gallon Plastic Marine Water or Waste Holding Tank by Ronco Plastics for only $220.00 Ronco Plastics 13 Gallon Plastic Marine Water or Waste Holding Tank 15.875 15.125 14.5 R-B262 $220.00
Buy 13 Gallon Plastic Marine Water Tank without Fittings by Ronco Plastics for only $348.00 13 Gallons Buy 13 Gallon Plastic Marine Water Tank without Fittings by Ronco Plastics for only $348.00 Ronco Plastics 13 Gallon Plastic Marine Water Tank without Fittings 36.5 17 10 R-B419 $348.00
Buy 13 Gallon RV Water Tank by Ronco Plastics for only $391.00 13 Gallons Buy 13 Gallon RV Water Tank by Ronco Plastics for only $391.00 Ronco Plastics 13 Gallon RV Water Tank 21 13 9.875 R-11W $391.00
Buy 13 Gallon Plastic Marine Water or Waste Holding Tank by Ronco Plastics for only $220.00 13 Gallons Buy 13 Gallon Plastic Marine Water or Waste Holding Tank by Ronco Plastics for only $220.00 Ronco Plastics 13 Gallon Plastic Marine Water or Waste Holding Tank 18.25 14.375 13.125 R-B266 $220.00
Buy 13 Gallon Plastic Marine Water Tank without Fittings by Ronco Plastics for only $256.00 13 Gallons Buy 13 Gallon Plastic Marine Water Tank without Fittings by Ronco Plastics for only $256.00 Ronco Plastics 13 Gallon Plastic Marine Water Tank without Fittings 48 10 9 R-B218 $256.00
Buy 14 Gallon Plastic Marine Water Tank without Fittings by Ronco Plastics for only $256.00 14 Gallons Buy 14 Gallon Plastic Marine Water Tank without Fittings by Ronco Plastics for only $256.00 Ronco Plastics 14 Gallon Plastic Marine Water Tank without Fittings 19.5 14.5 14.5 R-B238 $256.00
Buy 14 Gallon Plastic Marine Water Tank without Fittings by Ronco Plastics for only $275.00 14 Gallons Buy 14 Gallon Plastic Marine Water Tank without Fittings by Ronco Plastics for only $275.00 Ronco Plastics 14 Gallon Plastic Marine Water Tank without Fittings 27.5 21 15.75 R-B160 $275.00
Buy 14 Gallon Plastic Marine Water or Waste Holding Tank by Ronco Plastics for only $299.99 14 Gallons Buy 14 Gallon Plastic Marine Water or Waste Holding Tank by Ronco Plastics for only $299.99 Ronco Plastics 14 Gallon Plastic Marine Water or Waste Holding Tank 16.5 15.375 14 R-B534 $299.99
Buy 14 Gallon Plastic Marine Water or Waste Holding Tank by Ronco Plastics for only $220.00 14 Gallons Buy 14 Gallon Plastic Marine Water or Waste Holding Tank by Ronco Plastics for only $220.00 Ronco Plastics 14 Gallon Plastic Marine Water or Waste Holding Tank 15.625 15.625 15.125 R-B274 $220.00
Buy 14 Gallon Plastic Marine and RV Water or Waste Holding Tank by Ronco Plastics for only $246.00 14 Gallons Buy 14 Gallon Plastic Marine and RV Water or Waste Holding Tank by Ronco Plastics for only $246.00 Ronco Plastics 14 Gallon Plastic Marine and RV Water or Waste Holding Tank 17.5 14.5 14.25 R-B265 $246.00
Buy 14 Gallon Plastic Marine and RV Water or Waste Holding Tank by Trionic of White color for only $0.00 14 Gallons Buy 14 Gallon Plastic Marine and RV Water or Waste Holding Tank by Trionic of White color for only $0.00 Trionic 14 Gallon Plastic Marine and RV Water or Waste Holding Tank 20 14 11.75 TRI-2014-1 As low as$252.50
Buy 14 Gallon Plastic Marine and RV Water or Waste Holding Tank by Ronco Plastics for only $269.99 14 Gallons Buy 14 Gallon Plastic Marine and RV Water or Waste Holding Tank by Ronco Plastics for only $269.99 Ronco Plastics 14 Gallon Plastic Marine and RV Water or Waste Holding Tank 24.5 16.5 19.25 R-B245 $269.99
Buy 14 Gallon Plastic Marine and RV Water or Waste Holding Tank by Trionic for only $0.00 14 Gallons Buy 14 Gallon Plastic Marine and RV Water or Waste Holding Tank by Trionic for only $0.00 Trionic 14 Gallon Plastic Marine and RV Water or Waste Holding Tank 24 14 10 TRI-2014 As low as$252.50
Buy 15 Gallon Plastic Marine and RV Water or Waste Holding Tank by Ronco Plastics for only $225.00 15 Gallons Buy 15 Gallon Plastic Marine and RV Water or Waste Holding Tank by Ronco Plastics for only $225.00 Ronco Plastics 15 Gallon Plastic Marine and RV Water or Waste Holding Tank 20 15 12 R-B131 $225.00
Buy 15 Gallon Plastic Marine and RV Water or Waste Holding Tank by Ronco Plastics for only $269.99 15 Gallons Buy 15 Gallon Plastic Marine and RV Water or Waste Holding Tank by Ronco Plastics for only $269.99 Ronco Plastics 15 Gallon Plastic Marine and RV Water or Waste Holding Tank 20 13 13 R-B175 $269.99
Buy 15 Gallon Plastic Marine and RV Water or Waste Holding Tank by Ronco Plastics for only $269.99 15 Gallons Buy 15 Gallon Plastic Marine and RV Water or Waste Holding Tank by Ronco Plastics for only $269.99 Ronco Plastics 15 Gallon Plastic Marine and RV Water or Waste Holding Tank 17.5 16.75 13.75 R-B320 $269.99
Buy 15 Gallon Plastic Marine and RV Water or Waste Holding Tank by Trionic of White color for only $0.00 15 Gallons Buy 15 Gallon Plastic Marine and RV Water or Waste Holding Tank by Trionic of White color for only $0.00 Trionic 15 Gallon Plastic Marine and RV Water or Waste Holding Tank 19 18 9.75 TRI-2015 As low as$252.50
Buy 15 Gallon Plastic Marine Water Tank without Fittings by Ronco Plastics for only $238.00 15 Gallons Buy 15 Gallon Plastic Marine Water Tank without Fittings by Ronco Plastics for only $238.00 Ronco Plastics 15 Gallon Plastic Marine Water Tank without Fittings 21 17.5 13.25 R-B173 $238.00
Buy 15 Gallon Plastic Marine Water Tank without Fittings by Ronco Plastics for only $220.00 15 Gallons Buy 15 Gallon Plastic Marine Water Tank without Fittings by Ronco Plastics for only $220.00 Ronco Plastics 15 Gallon Plastic Marine Water Tank without Fittings 30.25 25.625 11.75 R-B492 $220.00
Buy 15 Gallon Plastic Marine and RV Water or Waste Holding Tank by Ronco Plastics for only $269.99 15 Gallons Buy 15 Gallon Plastic Marine and RV Water or Waste Holding Tank by Ronco Plastics for only $269.99 Ronco Plastics 15 Gallon Plastic Marine and RV Water or Waste Holding Tank 27.5 14.75 9.5 R-B251 $269.99
Buy 15 Gallon Plastic Marine and RV Water or Waste Holding Tank by Ronco Plastics for only $220.00 15 Gallons Buy 15 Gallon Plastic Marine and RV Water or Waste Holding Tank by Ronco Plastics for only $220.00 Ronco Plastics 15 Gallon Plastic Marine and RV Water or Waste Holding Tank 22 17 9.875 R-B264 $220.00
Buy 15 Gallon Plastic Marine and RV Water or Waste Holding Tank by Ronco Plastics for only $269.99 15 Gallons Buy 15 Gallon Plastic Marine and RV Water or Waste Holding Tank by Ronco Plastics for only $269.99 Ronco Plastics 15 Gallon Plastic Marine and RV Water or Waste Holding Tank 24 18.5 8.5 R-B388 $269.99
Buy 15 Gallon Plastic Marine Water or Waste Holding Tank by Ronco Plastics for only $275.00 15 Gallons Buy 15 Gallon Plastic Marine Water or Waste Holding Tank by Ronco Plastics for only $275.00 Ronco Plastics 15 Gallon Plastic Marine Water or Waste Holding Tank 23 19.5 14.75 R-B475 $275.00
Buy 16 Gallon Plastic Marine Water Tank without Fittings by Ronco Plastics for only $238.00 16 Gallons Buy 16 Gallon Plastic Marine Water Tank without Fittings by Ronco Plastics for only $238.00 Ronco Plastics 16 Gallon Plastic Marine Water Tank without Fittings 23 18.5 15.5 R-B107 $238.00
Buy 16 Gallon Plastic Marine and RV Water or Waste Holding Tank by Ronco Plastics for only $269.99 16 Gallons Buy 16 Gallon Plastic Marine and RV Water or Waste Holding Tank by Ronco Plastics for only $269.99 Ronco Plastics 16 Gallon Plastic Marine and RV Water or Waste Holding Tank 16 16 16 R-B106 $269.99
Buy 16 Gallon Plastic Marine and RV Water or Waste Holding Tank by Ronco Plastics for only $319.99 16 Gallons Buy 16 Gallon Plastic Marine and RV Water or Waste Holding Tank by Ronco Plastics for only $319.99 Ronco Plastics 16 Gallon Plastic Marine and RV Water or Waste Holding Tank 26 14 11 R-B526 $319.99
Buy 16 Gallon Plastic Marine Water Tank without Fittings by Ronco Plastics for only $311.00 16 Gallons Buy 16 Gallon Plastic Marine Water Tank without Fittings by Ronco Plastics for only $311.00 Ronco Plastics 16 Gallon Plastic Marine Water Tank without Fittings 29.25 15.5 12.75 R-B398 $311.00
Buy 16 Gallon Plastic Marine Water Tank without Fittings by Ronco Plastics for only $275.00 16 Gallons Buy 16 Gallon Plastic Marine Water Tank without Fittings by Ronco Plastics for only $275.00 Ronco Plastics 16 Gallon Plastic Marine Water Tank without Fittings 35.5 14.75 11.75 R-B215 $275.00
Buy 16 Gallon Plastic Marine Water Tank without Fittings by Ronco Plastics for only $293.00 16 Gallons Buy 16 Gallon Plastic Marine Water Tank without Fittings by Ronco Plastics for only $293.00 Ronco Plastics 16 Gallon Plastic Marine Water Tank without Fittings 30 15.75 12.75 R-B364 $293.00
Buy 16 Gallon Plastic Marine Water Tank without Fittings by Ronco Plastics for only $329.99 16 Gallons Buy 16 Gallon Plastic Marine Water Tank without Fittings by Ronco Plastics for only $329.99 Ronco Plastics 16 Gallon Plastic Marine Water Tank without Fittings 33 30 15 R-B373 $329.99
Buy 16 Gallon Plastic Marine Water Tank without Fittings by Ronco Plastics for only $311.00 16 Gallons Buy 16 Gallon Plastic Marine Water Tank without Fittings by Ronco Plastics for only $311.00 Ronco Plastics 16 Gallon Plastic Marine Water Tank without Fittings 29.75 12.75 12.5 R-B399 $311.00
Buy 16 Gallon Plastic RV or Marine Water or Waste Holding Tank by Ronco Plastics for only $449.00 16 Gallons Buy 16 Gallon Plastic RV or Marine Water or Waste Holding Tank by Ronco Plastics for only $449.00 Ronco Plastics 16 Gallon Plastic RV or Marine Water or Waste Holding Tank 23 21 9 R-36W $449.00
Buy 16 Gallon Plastic Marine Water Tank without Fittings by Ronco Plastics for only $238.00 16 Gallons Buy 16 Gallon Plastic Marine Water Tank without Fittings by Ronco Plastics for only $238.00 Ronco Plastics 16 Gallon Plastic Marine Water Tank without Fittings 37.125 12.75 10.625 R-B500 $238.00
Buy 17 Gallon Plastic RV or Marine Water or Waste Holding Tank by Ronco Plastics for only $456.00 17 Gallons Buy 17 Gallon Plastic RV or Marine Water or Waste Holding Tank by Ronco Plastics for only $456.00 Ronco Plastics 17 Gallon Plastic RV or Marine Water or Waste Holding Tank 38 15.5 8.125 R-20W $456.00
Buy 17 Gallon Plastic RV or Marine Water or Waste Holding Tank by Ronco Plastics for only $249.99 17 Gallons Buy 17 Gallon Plastic RV or Marine Water or Waste Holding Tank by Ronco Plastics for only $249.99 Ronco Plastics 17 Gallon Plastic RV or Marine Water or Waste Holding Tank 32 12 12 R-27W $249.99
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