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

  • 36 Gallon Marine Water Tank MW-503. Technical drawing of a polyethylene water tank designed for marine vessels.

    36 Gallon Marine Water Tank MW-503

    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-503, is engineered to meet the requirements of mobile...

    MSRP: $334.42
    $317.96
    Add to Cart
  • 36 Gallon Marine Water Tank MW-469. Technical drawing of a polyethylene water tank designed for marine vessels.

    36 Gallon Marine Water Tank MW-469

    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-469, is engineered to meet the requirements of mobile...

    MSRP: $398.69
    $379.07
    Add to Cart
  • 36 Gallon Marine Water Tank MW-3. Technical drawing of a polyethylene water tank designed for marine vessels.

    36 Gallon Marine Water Tank MW-3

    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-3, is engineered to meet the requirements of mobile...

    MSRP: $377.57
    $358.99
    Add to Cart
  • An image of a 30 Gallon Marine Fresh Water Tank | B502

    37 Gallon Marine Fresh Water Tank | BOAT17W

    Introducing the 37 Gallon Marine Fresh Water Tank by One Clarion. This rectangular tank is designed specifically for marine water storage. With its portable usability, you can easily transport and set up this tank above ground. The tank is made from...

    $397.67
    Add to Cart
  • An image of a 27 Gallon Marine Holding Tank | B342

    37 Gallon Marine Fresh Water Tank | B489

    Introducing the 37 Gallon Marine Fresh Water Tank by One Clarion. This rectangular tank is designed specifically for marine water storage and is perfect for both above ground and portable use. Made from high-quality polyethylene, this tank is durable and...

    $397.67
    Add to Cart
  • An image of a 9 Gallon Marine Fresh Water Tank | B288

    37 Gallon Marine Fresh Water Tank | B372

    Introducing the 37 Gallon Marine Fresh Water Tank by One Clarion. This rectangular tank is designed specifically for marine water storage and is perfect for portable use. With its above ground environment, you can easily set it up wherever you need it...

    $397.67
    Add to Cart
  • Image of a 37 Gallon Trionic Marine Fresh Water Tank

    37 Gallon Trionic Marine Fresh Water Tank | WH-2037-1

    The 37 Gallon Trionic 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...

    $552.33
    Add to Cart
  • Image of a 37 Gallon Trionic Marine Fresh Water Tank

    37 Gallon Trionic Marine Fresh Water Tank | WH-2037

    Introducing the 37 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 nature allows for convenient transportation, perfect for those who...

    $552.33
    Add to Cart
  • Image of a 37 Gallon Trionic Marine Fresh Water Tank

    37 Gallon Trionic Marine Fresh Water Tank | WH-2037-2

    The 37 Gallon Trionic Marine Fresh Water Tank 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...

    $552.33
    Add to Cart
  • 37 Gallon Marine Water Tank MW-478. Technical drawing of a polyethylene water tank designed for marine vessels.

    37 Gallon Marine Water Tank MW-478

    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 37 Gallon Marine Water Tank, Part# MW-478, is engineered to meet the requirements of mobile...

    MSRP: $462.51
    $439.74
    Add to Cart
  • 37 Gallon Marine Water Tank MW-452. Technical drawing of a polyethylene water tank designed for marine vessels.

    37 Gallon Marine Water Tank MW-452

    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 37 Gallon Marine Water Tank, Part# MW-452, is engineered to meet the requirements of mobile...

    MSRP: $285.80
    $271.73
    Add to Cart
  • 37 Gallon Marine Water Tank MW-259. Technical drawing of a polyethylene water tank designed for marine vessels.

    37 Gallon Marine Water Tank MW-259

    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 37 Gallon Marine Water Tank, Part# MW-259, is engineered to meet the requirements of mobile...

    MSRP: $300.45
    $285.66
    Add to Cart