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

  • 16 Gallon Marine Water Tank MW-559. Technical drawing of a polyethylene water tank designed for marine vessels.

    16 Gallon Marine Water Tank MW-559

    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 16 Gallon Marine Water Tank, Part# MW-559, is engineered to meet the requirements of mobile...

    MSRP: $232.17
    $220.74
    Add to Cart
  • 16 Gallon Marine Water Tank MW-551. Technical drawing of a polyethylene water tank designed for marine vessels.

    16 Gallon Marine Water Tank MW-551

    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 16 Gallon Marine Water Tank, Part# MW-551, is engineered to meet the requirements of mobile...

    MSRP: $258.66
    $245.92
    Add to Cart
  • 16 Gallon Marine Water Tank MW-492. Technical drawing of a polyethylene water tank designed for marine vessels.

    16 Gallon Marine Water Tank MW-492

    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 16 Gallon Marine Water Tank, Part# MW-492, is engineered to meet the requirements of mobile...

    MSRP: $223.33
    $212.33
    Add to Cart
  • 16 Gallon Marine Water Tank MW-27. Technical drawing of a polyethylene water tank designed for marine vessels.

    16 Gallon Marine Water Tank MW-27

    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 16 Gallon Marine Water Tank, Part# MW-27, is engineered to meet the requirements of mobile...

    MSRP: $192.82
    $183.33
    Add to Cart
  • An image of a 138 Gallon PE Ronco White Rectangular Open Top Tank | 40X18X48PE

    17 Gallon Marine Fresh Water Tank | BOAT27W

    The 17 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...

    $269.13
    Add to Cart
  • An image of a 40 Gallon Marine Holding Tank | B222

    17 Gallon Marine Fresh Water Tank | BOAT20W

    Upgrade your marine vessel with the 17 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...

    $269.13
    Add to Cart
  • An image of a 65 Gallon Marine Holding Tank | B297

    17 Gallon Marine Fresh Water Tank | B462

    The 17 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, this tank is designed to fit easily in various spaces on your boat or other marine vessels...

    $281.18
    Add to Cart
  • An image of a 20 Gallon Marine Fresh Water Tank | B231

    17 Gallon Marine Fresh Water Tank | B359

    Introducing the 17 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...

    $256.08
    Add to Cart
  • An image of a 40 Gallon Marine Holding Tank | B305

    17 Gallon Marine Fresh Water Tank | B325

    Introducing the 17 Gallon Marine Fresh Water Tank by One Clarion. This portable tank is specifically designed for marine use, making it perfect for boats and other watercraft. With its rectangular shape, it can easily fit in tight spaces and maximize...

    $256.08
    Add to Cart
  • An image of a 10 Gallon Marine Fresh Water Tank | B278

    17 Gallon Marine Fresh Water Tank | B226

    Upgrade your marine vessel with the 17 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...

    $246.04
    Add to Cart
  • An image of a 30 Gallon Marine Fresh Water Tank | B202

    17 Gallon Marine Fresh Water Tank | B123

    Introducing the 17 Gallon Marine Fresh Water Tank by One Clarion. This portable tank is perfect for marine use, with a rectangular shape that allows for easy storage and transportation. Made from durable polyethylene material, this tank is built to...

    $268.13
    Add to Cart
  • An image of a 20 Gallon Marine Fresh Water Tank | B187

    18 Gallon Marine Fresh Water Tank | B527

    Introducing the 18 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 its rectangular shape, it can easily fit in tight spaces and maximize...

    $326.38
    Add to Cart