Marine Water Tanks

These NSF and FDA compliant marine water storage tanks are made to be incredibly strong, nearly unbreakable, and are very affordable. Plastic marine water tanks (poly) are available in nearly every size and shape. Made from one piece of thick poly, there are no seams so less opportunity for leaking, and made with a rotomold process for superior strength. You won’t find better-made marine fresh water tanks for the price. 

Made from one piece to form 3/8” thick walls using a roto-mold process to create a seamless holding tank superior in strength and performance. These custom fitted marine water tanks are built to go the distance.   

*Note: Customize the placement of the fittings when you place the order.  We spin-weld the fittings to ensure your holding tank is securely connected to your plumbing.

  • Complies with NSF 61, FDA Reg CFR 177.1520, and Coast Guard Standards
  • Made from virgin polyethylene (poly) resins
  • Seamless tank made from one piece (less likely to break or leak)
  • 3/8” thick tank walls
  • Customized fitting placement
  • Spin weld fittings
  • Outlasts the competition

For use as marine water tanks, marine fresh water tanks, plastic marine water tanks, poly marine water tanks, custom marine water tanks, and more!

We have 100’s of sizes ranging from 2 gallons, 40 gallons, 50 gallons, 100 gallon marine water tanks.  They range in size up to 250 gallons for these poly marine fresh water tanks.

Looking for something else? Chances are, we have it, and at affordable prices too!  Just call us and ask!

Pick the size and shape you need from the list. Mark up the drawing with your fittings placement. Call us with any questions!

Marine Water Tanks

  • An image of a 65 Gallon Marine Holding Tank | B324

    33 Gallon Marine Fresh Water Tank | B397

    The 33 Gallon Marine Fresh Water Tank offered by One Clarion is a versatile and portable solution for your marine water storage needs. With its rectangular shape, this tank is designed to fit easily in your boat or other marine vessel. Made from durable...

    $432.83
    Add to Cart
  • 33 Gallon Marine Water Tank MW-558. Technical drawing of a polyethylene water tank designed for marine vessels.

    33 Gallon Marine Water Tank MW-558

    This tank ships in 6-8 weeks. Custom fitting placement is not available at this time. It can be ordered blank, or blank with a DIY Fitting Kit Custom Roto-Mold 33 Gallon Marine Water Tank, Part# MW-558, is engineered to meet the requirements of mobile...

    MSRP: $311.82
    $296.48
    Add to Cart
  • 33 Gallon Marine Water Tank MW-525. Technical drawing of a polyethylene water tank designed for marine vessels.

    33 Gallon Marine Water Tank MW-525

    This tank ships in 6-8 weeks. Custom fitting placement is not available at this time. It can be ordered blank, or blank with a DIY Fitting Kit Custom Roto-Mold 33 Gallon Marine Water Tank, Part# MW-525, is engineered to meet the requirements of mobile...

    MSRP: $325.47
    $309.44
    Add to Cart
  • 33 Gallon Marine Water Tank MW-332. Technical drawing of a polyethylene water tank designed for marine vessels.

    33 Gallon Marine Water Tank MW-332

    This tank ships in 6-8 weeks. Custom fitting placement is not available at this time. It can be ordered blank, or blank with a DIY Fitting Kit Custom Roto-Mold 33 Gallon Marine Water Tank, Part# MW-332, is engineered to meet the requirements of mobile...

    MSRP: $364.83
    $346.87
    Add to Cart
  • 33 Gallon Marine Water Tank MW-30. Technical drawing of a polyethylene water tank designed for marine vessels.

    33 Gallon Marine Water Tank MW-30

    This tank ships in 6-8 weeks. Custom fitting placement is not available at this time. It can be ordered blank, or blank with a DIY Fitting Kit Custom Roto-Mold 33 Gallon Marine Water Tank, Part# MW-30, is engineered to meet the requirements of mobile...

    MSRP: $306.32
    $291.24
    Add to Cart
  • 33 Gallon Marine Water Tank MW-237. Technical drawing of a polyethylene water tank designed for marine vessels.

    33 Gallon Marine Water Tank MW-237

    This tank ships in 6-8 weeks. Custom fitting placement is not available at this time. It can be ordered blank, or blank with a DIY Fitting Kit Custom Roto-Mold 33 Gallon Marine Water Tank, Part# MW-237, is engineered to meet the requirements of mobile...

    MSRP: $286.30
    $272.21
    Add to Cart
  • An image of a 40 Gallon Marine Fresh Water Tank | B439

    34 Gallon Marine Fresh Water Tank | B538

    The 34 Gallon Marine Fresh Water Tank by One Clarion is a rectangular-shaped portable tank designed for above ground use. This tank is made of high-quality polyethylene material in natural white color. It measures 26 inches in length, 22 inches in width,...

    $502.11
    Add to Cart
  • An image of a 68 Gallon RV Holding Tank | RV80H

    34 Gallon Marine Fresh Water Tank | B471

    Introducing the 34 Gallon Marine Fresh Water Tank by One Clarion. This portable tank is designed specifically for marine use, making it the perfect solution for your fresh water needs while out on the water. With a rectangular shape and a capacity of 34...

    $466.97
    Add to Cart
  • An image of a 50 Gallon Marine Holding Tank | BOAT8W

    34 Gallon Marine Fresh Water Tank | B381

    The 34 Gallon Marine Fresh Water Tank from One Clarion is a rectangular, portable tank designed for above ground use. Made from polyethylene in a natural white color, this tank is 34" in length, 26" in width, and 9 1/2" in height. It is not designed for...

    $350.48
    Add to Cart
  • Image of a 34 Gallon Trionic Marine Fresh Water Tank

    34 Gallon Trionic Marine Fresh Water Tank | WH-2034

    The 34 Gallon Trionic Marine Fresh Water Tank is a portable and above ground water tank designed specifically for marine use. Its rectangular shape allows for easy installation and placement on boats or other water vessels. Made from durable polyethylene...

    $492.07
    Add to Cart
  • 34 Gallon Marine Water Tank MW-482. Technical drawing of a polyethylene water tank designed for marine vessels.

    34 Gallon Marine Water Tank MW-482

    This tank ships in 6-8 weeks. Custom fitting placement is not available at this time. It can be ordered blank, or blank with a DIY Fitting Kit Custom Roto-Mold 34 Gallon Marine Water Tank, Part# MW-482, is engineered to meet the requirements of mobile...

    MSRP: $323.90
    $307.95
    Add to Cart
  • 34 Gallon Marine Water Tank MW-234. Technical drawing of a polyethylene water tank designed for marine vessels.

    34 Gallon Marine Water Tank MW-234

    This tank ships in 6-8 weeks. Custom fitting placement is not available at this time. It can be ordered blank, or blank with a DIY Fitting Kit Custom Roto-Mold 34 Gallon Marine Water Tank, Part# MW-234, is engineered to meet the requirements of mobile...

    MSRP: $393.45
    $374.09
    Add to Cart