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 80 Gallon Marine Fresh Water Tank | B299

    21 Gallon Marine Fresh Water Tank | B503

    Introducing the 21 Gallon Marine Fresh Water Tank by One Clarion. This portable tank is perfect for marine environments and is designed to be used above ground. With its rectangular shape, it offers a space-saving solution for storing and transporting...

    $397.67
    Add to Cart
  • An image of a 90 Gallon Marine Fresh Water Tank | B314

    21 Gallon Marine Fresh Water Tank | B490

    Introducing the 21 Gallon Marine Fresh Water Tank by One Clarion. This portable tank is perfect for marine environments and is designed to be used above ground. With its rectangular shape and dimensions of 30" Length x 18" Width x 11 7/8" Height, it...

    $362.53
    Add to Cart
  • An image of a 5 Gallon Marine Holding Tank | B377

    21 Gallon Marine Fresh Water Tank | B396

    Introducing the 21 Gallon Marine Fresh Water Tank by One Clarion. This portable tank is perfect for marine environments and is designed to be used above ground. With its rectangular shape, it offers a space-saving solution for storing fresh water on your...

    $362.53
    Add to Cart
  • An image of a 15 Gallon Marine Holding Tank | B264

    21 Gallon Marine Fresh Water Tank | B355

    The 21 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 53 1/2" in length, 16 3/4" in width, and 6" in height. It is not designed...

    $326.38
    Add to Cart
  • An image of a 14 Gallon Marine Fresh Water Tank | B265

    21 Gallon Marine Fresh Water Tank | B281

    The 21 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 19 7/8" in length, 16 7/8" in width, and 16 3/8" in height. It is not...

    $315.32
    Add to Cart
  • An image of a 80 Gallon Marine Holding Tank | B299

    21 Gallon Marine Fresh Water Tank | B219

    The 21 Gallon Marine Fresh Water Tank by One Clarion is the perfect solution for your portable marine water needs. This rectangular tank is designed for above ground use and is made from high-quality polyethylene material in a natural white color. The...

    $339.43
    Add to Cart
  • An image of a 52 Gallon Marine Fresh Water Tank | B295

    21 Gallon Marine Fresh Water Tank | B151

    Introducing the 21 Gallon Marine Fresh Water Tank by One Clarion. This portable tank is perfect for marine environments and is designed to be used above ground. With its rectangular shape and dimensions of 41 1/2" Length x 17 1/2" Width x 11" Height, it...

    $327.38
    Add to Cart
  • An image of a 21 Gallon Marine Holding Tank | B151

    21 Gallon Marine Fresh Water Tank | B148

    The 21 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...

    $304.28
    Add to Cart
  • An image of a 30 Gallon Marine Holding Tank | B140

    21 Gallon Marine Fresh Water Tank | B110

    Introducing the 21 Gallon Marine Fresh Water Tank by One Clarion. This portable tank is perfect for marine environments and is designed to be used above ground. With its rectangular shape and dimensions of 28" Length x 13 1/4" Width x 20" Height, it...

    $304.28
    Add to Cart
  • 21 Gallon Marine Water Tank MW-555. Technical drawing of a polyethylene water tank designed for marine vessels.

    21 Gallon Marine Water Tank MW-555

    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 21 Gallon Marine Water Tank, Part# MW-555, is engineered to meet the requirements of mobile...

    MSRP: $364.15
    $346.22
    Add to Cart
  • 21 Gallon Marine Water Tank MW-526. Technical drawing of a polyethylene water tank designed for marine vessels.

    21 Gallon Marine Water Tank MW-526

    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 21 Gallon Marine Water Tank, Part# MW-526, is engineered to meet the requirements of mobile...

    MSRP: $263.54
    $250.57
    Add to Cart
  • 21 Gallon Marine Water Tank MW-413. Technical drawing of a polyethylene water tank designed for marine vessels.

    21 Gallon Marine Water Tank MW-413

    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 21 Gallon Marine Water Tank, Part# MW-413, is engineered to meet the requirements of mobile...

    MSRP: $275.15
    $261.61
    Add to Cart