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 43 Gallon Marine Holding Tank | BOAT22W

    47 Gallon Marine Fresh Water Tank | B507

    Upgrade your marine vessel with the 47 Gallon Marine Fresh Water Tank from One Clarion. This rectangular tank is designed for portable use and is suitable for above ground environments. Made from polyethylene in a natural white color, this tank measures...

    $431.82
    Add to Cart
  • 47 Gallon Marine Water Tank MW-537. Technical drawing of a polyethylene water tank designed for marine vessels.

    47 Gallon Marine Water Tank MW-537

    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 47 Gallon Marine Water Tank, Part# MW-537, is engineered to meet the requirements of mobile...

    MSRP: $845.26
    $803.65
    Add to Cart
  • An image of a 9 Gallon RV Holding Tank | RV36H

    48 Gallon Marine Fresh Water Tank | B491

    Upgrade your marine vessel with the 48 Gallon Marine Fresh Water Tank from One Clarion. This rectangular tank is designed for portable use and is suitable for above ground environments. Made from polyethylene in a natural white color, this tank measures...

    $491.07
    Add to Cart
  • An image of a 22 Gallon Marine Fresh Water Tank | B463

    48 Gallon Marine Fresh Water Tank | B384

    Introducing the 48 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 generous capacity of 48 gallons, providing ample...

    $550.32
    Add to Cart
  • An image of a 3 Gallon Marine Fresh Water Tank | BOAT13W

    48 Gallon Marine Fresh Water Tank | B306

    Upgrade your marine vessel with the 48 Gallon Marine Fresh Water Tank from One Clarion. This rectangular tank is designed for portable use and is suitable for above ground environments. Made from polyethylene in a natural white color, this tank measures...

    $491.07
    Add to Cart
  • An image of a 47 Gallon Marine Fresh Water Tank | B507

    48 Gallon Marine Fresh Water Tank | B293

    Introducing the 48 Gallon Marine Fresh Water Tank by One Clarion. This portable tank is designed specifically for marine use, making it the perfect solution for your fresh water needs while out on the water. With a rectangular shape and a capacity of 48...

    $573.42
    Add to Cart
  • An image of a 20 Gallon RV Holding Tank | RV24H

    48 Gallon Marine Fresh Water Tank | B229

    Introducing the 48 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 is easy to fit into tight spaces on...

    $491.07
    Add to Cart
  • 48 Gallon Marine Water Tank MW-79. Technical drawing of a polyethylene water tank designed for marine vessels.

    48 Gallon Marine Water Tank MW-79

    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 48 Gallon Marine Water Tank, Part# MW-79, is engineered to meet the requirements of mobile...

    MSRP: $406.31
    $386.31
    Add to Cart
  • 48 Gallon Marine Water Tank MW-514. Technical drawing of a polyethylene water tank designed for marine vessels.

    48 Gallon Marine Water Tank MW-514

    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 48 Gallon Marine Water Tank, Part# MW-514, is engineered to meet the requirements of mobile...

    MSRP: $426.10
    $405.12
    Add to Cart
  • 48 Gallon Marine Water Tank MW-445. Technical drawing of a polyethylene water tank designed for marine vessels.

    48 Gallon Marine Water Tank MW-445

    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 48 Gallon Marine Water Tank, Part# MW-445, is engineered to meet the requirements of mobile...

    MSRP: $576.70
    $548.31
    Add to Cart
  • 48 Gallon Marine Water Tank MW-319. Technical drawing of a polyethylene water tank designed for marine vessels.

    48 Gallon Marine Water Tank MW-319

    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 48 Gallon Marine Water Tank, Part# MW-319, is engineered to meet the requirements of mobile...

    MSRP: $453.21
    $430.90
    Add to Cart
  • 48 Gallon Marine Water Tank MW-279. Technical drawing of a polyethylene water tank designed for marine vessels.

    48 Gallon Marine Water Tank MW-279

    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 48 Gallon Marine Water Tank, Part# MW-279, is engineered to meet the requirements of mobile...

    MSRP: $531.08
    $504.94
    Add to Cart