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 115 Gallon Marine Fresh Water Tank | B328

    42 Gallon Marine Fresh Water Tank | B182

    The 42 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 and above ground usability, this tank is designed to fit seamlessly into your boat or marine...

    $408.72
    Add to Cart
  • An image of a 115 Gallon Marine Holding Tank | B328

    42 Gallon Marine Fresh Water Tank | B119

    Introducing the 42 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-efficient solution for...

    $432.83
    Add to Cart
  • 42 Gallon Marine Water Tank MW-464. Technical drawing of a polyethylene water tank designed for marine vessels.

    42 Gallon Marine Water Tank MW-464

    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 42 Gallon Marine Water Tank, Part# MW-464, is engineered to meet the requirements of mobile...

    MSRP: $379.36
    $360.69
    Add to Cart
  • 42 Gallon Marine Water Tank MW-405. Technical drawing of a polyethylene water tank designed for marine vessels.

    42 Gallon Marine Water Tank MW-405

    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 42 Gallon Marine Water Tank, Part# MW-405, is engineered to meet the requirements of mobile...

    MSRP: $618.00
    $587.57
    Add to Cart
  • 42 Gallon Marine Water Tank MW-204. Technical drawing of a polyethylene water tank designed for marine vessels.

    42 Gallon Marine Water Tank MW-204

    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 42 Gallon Marine Water Tank, Part# MW-204, is engineered to meet the requirements of mobile...

    MSRP: $420.97
    $400.25
    Add to Cart
  • An image of a 35 Gallon Marine Holding Tank | B445

    43 Gallon Marine Fresh Water Tank | BOAT22W

    Introducing the 43 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-efficient solution for...

    $421.77
    Add to Cart
  • An image of a 15 Gallon Marine Holding Tank | B251

    43 Gallon Marine Fresh Water Tank | B368

    The 43 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 and above ground usability, this tank is designed to fit seamlessly into your boat or marine...

    $443.87
    Add to Cart
  • An image of a 110 Gallon Marine Holding Tank | B391

    43 Gallon Marine Fresh Water Tank | B220

    Introducing the 43 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...

    $431.82
    Add to Cart
  • 43 Gallon Marine Water Tank MW-250. Technical drawing of a polyethylene water tank designed for marine vessels.

    43 Gallon Marine Water Tank MW-250

    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 43 Gallon Marine Water Tank, Part# MW-250, is engineered to meet the requirements of mobile...

    MSRP: $354.97
    $337.49
    Add to Cart
  • An image of a 155 Gallon RV Fresh Water Tank | B392

    44 Gallon Marine Fresh Water Tank | BOAT9W

    Introducing the 44 Gallon Marine Fresh Water Tank by One Clarion. This portable tank is specifically designed for marine use, making it perfect for boats and other water vessels. With a rectangular shape and a capacity of 44 gallons, this tank provides...

    $456.93
    Add to Cart
  • An image of a 75 Gallon RV Fresh Water Tank | RV61W

    44 Gallon Marine Fresh Water Tank | B440

    Introducing the 44 Gallon Marine Fresh Water Tank by One Clarion. This portable tank is designed specifically for marine use, making it the perfect solution for storing fresh water on your boat or yacht. With a rectangular shape and a capacity of 44...

    $608.57
    Add to Cart
  • An image of a 5 Gallon RV Fresh Water Tank | RVB268

    44 Gallon Marine Fresh Water Tank | B414

    Introducing the 44 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 enthusiasts. With its portable design, you can easily transport and install...

    $608.57
    Add to Cart