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

  • 125 Gallon Marine Water Tank MW-238. Technical drawing of a polyethylene water tank designed for marine vessels.

    125 Gallon Marine Water Tank MW-238

    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 125 Gallon Marine Water Tank, Part# MW-238, is engineered to meet the requirements of mobile...

    MSRP: $1,136.80
    $1,080.83
    Add to Cart
  • An image of a 8 Gallon RV Fresh Water Tank | RVB270

    130 Gallon Marine Fresh Water Tank | B467

    Introducing the 130 Gallon Marine Fresh Water Tank by One Clarion. This rectangular tank is designed specifically for marine use, making it the perfect choice for boat owners and marine enthusiasts. With a portable design, this tank can be easily...

    $900.81
    Add to Cart
  • An image of a 27 Gallon RV Holding Tank | RV6H

    130 Gallon Marine Fresh Water Tank | B356

    Introducing the 130 Gallon Marine Fresh Water Tank by One Clarion. This portable tank is specifically designed for marine water storage, making it perfect for boats and other water vessels. With its rectangular shape, it offers a space-efficient solution...

    $865.65
    Add to Cart
  • Image of a 130 Gallon Trionic Marine Fresh Water Tank

    130 Gallon Trionic Marine Fresh Water Tank | WH-2130

    Introducing the 130 Gallon Trionic Marine Fresh Water Tank by One Clarion. This marine water tank is designed with a rectangular shape, making it easy to fit into any space. Its portable usability allows for convenient transportation, while its above...

    $1,104.66
    Add to Cart
  • 130 Gallon Marine Water Tank MW-450. Technical drawing of a polyethylene water tank designed for marine vessels.

    130 Gallon Marine Water Tank MW-450

    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 130 Gallon Marine Water Tank, Part# MW-450, is engineered to meet the requirements of mobile...

    MSRP: $1,226.50
    $1,166.11
    Add to Cart
  • 132 Gallon Marine Water Tank MW-347. Technical drawing of a polyethylene water tank designed for marine vessels.

    132 Gallon Marine Water Tank MW-347

    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 132 Gallon Marine Water Tank, Part# MW-347, is engineered to meet the requirements of mobile...

    MSRP: $1,108.34
    $1,053.77
    Add to Cart
  • An image of a 20 Gallon RV Fresh Water Tank | RVB231

    135 Gallon Marine Fresh Water Tank | B407

    Introducing the 135 Gallon Marine Fresh Water Tank by One Clarion. This portable tank is specifically designed for marine water storage, making it perfect for boating and other water-related activities. With its rectangular shape, it offers a...

    $876.71
    Add to Cart
  • An image of a 13 Gallon RV Holding Tank | RV46H

    135 Gallon Marine Fresh Water Tank | B300

    One Clarion is proud to present the 135 Gallon Marine Fresh Water Tank. This marine water tank is designed in a rectangular shape, making it easy to fit into any space. With its portable usability, you can take this tank with you wherever you go. The...

    $876.71
    Add to Cart
  • 135 Gallon Marine Water Tank MW-239. Technical drawing of a polyethylene water tank designed for marine vessels.

    135 Gallon Marine Water Tank MW-239

    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 135 Gallon Marine Water Tank, Part# MW-239, is engineered to meet the requirements of mobile...

    MSRP: $1,226.50
    $1,166.11
    Add to Cart
  • An image of a 14 Gallon RV Fresh Water Tank | RVB265

    141 Gallon Marine Fresh Water Tank | B484

    The 141 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 in a natural white color, measuring 53 inches in length, 35 inches in width, and 19...

    $900.81
    Add to Cart
  • 142 Gallon Marine Water Tank MW-474. Technical drawing of a polyethylene water tank designed for marine vessels.

    142 Gallon Marine Water Tank MW-474

    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 142 Gallon Marine Water Tank, Part# MW-474, is engineered to meet the requirements of mobile...

    MSRP: $870.96
    $828.08
    Add to Cart
  • 142 Gallon Marine Water Tank MW-272. Technical drawing of a polyethylene water tank designed for marine vessels.

    142 Gallon Marine Water Tank MW-272

    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 142 Gallon Marine Water Tank, Part# MW-272, is engineered to meet the requirements of mobile...

    MSRP: $1,167.85
    $1,110.35
    Add to Cart