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

  • 35 Gallon Marine Water Tank MW-412. Technical drawing of a polyethylene water tank designed for marine vessels.

    35 Gallon Marine Water Tank MW-412

    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 35 Gallon Marine Water Tank, Part# MW-412, is engineered to meet the requirements of mobile...

    MSRP: $378.50
    $359.86
    Add to Cart
  • 35 Gallon Marine Water Tank MW-363. Technical drawing of a polyethylene water tank designed for marine vessels.

    35 Gallon Marine Water Tank MW-363

    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 35 Gallon Marine Water Tank, Part# MW-363, is engineered to meet the requirements of mobile...

    MSRP: $479.51
    $455.91
    Add to Cart
  • 35 Gallon Marine Water Tank MW-322. Technical drawing of a polyethylene water tank designed for marine vessels.

    35 Gallon Marine Water Tank MW-322

    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 35 Gallon Marine Water Tank, Part# MW-322, is engineered to meet the requirements of mobile...

    MSRP: $309.25
    $294.02
    Add to Cart
  • An image of a 42 Gallon Marine Holding Tank | B443

    36 Gallon Marine Fresh Water Tank | B478

    Introducing the 36 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 spacious capacity of 36 gallons, providing ample...

    $362.53
    Add to Cart
  • An image of a 7 Gallon RV Fresh Water Tank | RVB275

    36 Gallon Marine Fresh Water Tank | B428

    Introducing the 36 Gallon Marine Fresh Water Tank by One Clarion. This portable tank is specifically designed for marine use, making it perfect for boating and other water activities. With its rectangular shape and above ground usability, it offers...

    $373.57
    Add to Cart
  • An image of a 22 Gallon RV Holding Tank | RV99H

    36 Gallon Marine Fresh Water Tank | B383

    Introducing the 36 Gallon Marine Fresh Water Tank by One Clarion. This portable tank is specifically designed for marine use, making it perfect for boating and other water activities. With its rectangular shape and above ground usability, it offers...

    $408.72
    Add to Cart
  • An image of a 29 Gallon Marine Fresh Water Tank | B423

    36 Gallon Marine Fresh Water Tank | B340

    Introducing the 36 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 spacious capacity of 36 gallons, allowing you to...

    $397.67
    Add to Cart
  • An image of a 22 Gallon Marine Fresh Water Tank | B473

    36 Gallon Marine Fresh Water Tank | B330

    Introducing the 36 Gallon Marine Fresh Water Tank by One Clarion! This portable tank is perfect for marine enthusiasts who need a reliable and convenient water storage solution. With its rectangular shape and above ground usability, this tank is designed...

    $421.77
    Add to Cart
  • An image of a 135 Gallon RV Fresh Water Tank | B300

    36 Gallon Marine Fresh Water Tank | B254

    Introducing the 36 Gallon Marine Fresh Water Tank by One Clarion. This portable tank is specifically designed for marine use, making it perfect for boating and other water activities. With its rectangular shape, it offers a space-saving solution while...

    $373.57
    Add to Cart
  • An image of a 36 Gallon Marine Holding Tank | B428

    36 Gallon Marine Fresh Water Tank | B158

    The 36 Gallon Marine Fresh Water Tank by One Clarion is a rectangular-shaped portable tank designed for above ground use. This tank is made of polyethylene material and comes in a natural white color. It measures 30 1/2" in length, 21 1/2" in width, and...

    $373.57
    Add to Cart
  • Image of a 36 Gallon Trionic Marine Fresh Water Tank

    36 Gallon Trionic Marine Fresh Water Tank | WH-2036

    The 36 Gallon Trionic Marine Fresh Water Tank is a versatile and portable solution for your marine water storage needs. With its rectangular shape and above ground usability, this tank is designed to fit seamlessly into your boat or marine vessel. Made...

    $512.16
    Add to Cart
  • 36 Gallon Marine Water Tank MW-531. Technical drawing of a polyethylene water tank designed for marine vessels.

    36 Gallon Marine Water Tank MW-531

    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 36 Gallon Marine Water Tank, Part# MW-531, is engineered to meet the requirements of mobile...

    MSRP: $503.25
    $478.48
    Add to Cart