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!

Shop by Category

Marine Water Tanks

  • An image of a 33 Gallon RV Holding Tank | RV52H

    70 Gallon Marine Fresh Water Tank | B154

    This 70-gallon Ronco marine fresh water tank (B154) is built for onboard potable water storage on boats and watercraft. Measuring 36 1/2" x 28 1/2" x 25 1/2", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended...

    $608.57
    Add to Cart
  • An image of a 9 Gallon RV Fresh Water Tank | RV56W

    70 Gallon Marine Fresh Water Tank | B153

    This 70-gallon Ronco marine fresh water tank (B153) is built for onboard potable water storage on boats and watercraft. Measuring 36 1/2" x 28 1/2" x 25 1/2", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended...

    $608.57
    Add to Cart
  • 70 Gallon Marine Water Tank MW-84. Technical drawing of a polyethylene water tank designed for marine vessels.

    70 Gallon Marine Water Tank MW-84

    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 70 Gallon Marine Water Tank, Part# MW-84, is engineered to meet the requirements of mobile...

    MSRP: $482.99
    $459.20
    Add to Cart
  • 70 Gallon Marine Water Tank MW-481. Technical drawing of a polyethylene water tank designed for marine vessels.

    70 Gallon Marine Water Tank MW-481

    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 70 Gallon Marine Water Tank, Part# MW-481, is engineered to meet the requirements of mobile...

    MSRP: $703.37
    $668.75
    Add to Cart
  • An image of a 200 Gallon RV Fresh Water Tank | B485

    71 Gallon Marine Fresh Water Tank | B531

    This 71-gallon Ronco marine fresh water tank (B531) is built for onboard potable water storage on boats and watercraft. Measuring 63 1/4" x 23 1/8" x 12 1/2", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended...

    $549.32
    Add to Cart
  • 72 Gallon Marine Water Tank MW-546. Technical drawing of a polyethylene water tank designed for marine vessels.

    72 Gallon Marine Water Tank MW-546

    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 72 Gallon Marine Water Tank, Part# MW-546, is engineered to meet the requirements of mobile...

    MSRP: $935.99
    $889.91
    Add to Cart
  • 72 Gallon Marine Water Tank MW-213. Technical drawing of a polyethylene water tank designed for marine vessels.

    72 Gallon Marine Water Tank MW-213

    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 72 Gallon Marine Water Tank, Part# MW-213, is engineered to meet the requirements of mobile...

    MSRP: $415.62
    $395.16
    Add to Cart
  • 72 Gallon Marine Water Tank MW-211. Technical drawing of a polyethylene water tank designed for marine vessels.

    72 Gallon Marine Water Tank MW-211

    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 72 Gallon Marine Water Tank, Part# MW-211, is engineered to meet the requirements of mobile...

    MSRP: $567.96
    $540.00
    Add to Cart
  • 74 Gallon Marine Water Tank MW-34. Technical drawing of a polyethylene water tank designed for marine vessels.

    74 Gallon Marine Water Tank MW-34

    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 74 Gallon Marine Water Tank, Part# MW-34, is engineered to meet the requirements of mobile...

    MSRP: $554.29
    $527.00
    Add to Cart
  • An image of a 100 Gallon Marine Fresh Water Tank | B455

    75 Gallon Marine Fresh Water Tank | BOAT61W

    This 75-gallon Ronco marine fresh water tank (BOAT61W) is built for onboard potable water storage on boats and watercraft. Measuring 54" x 22" x 16", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on...

    $573.42
    Add to Cart
  • An image of a 18 Gallon Marine Fresh Water Tank | B345

    75 Gallon Marine Fresh Water Tank | B334

    This 75-gallon Ronco marine fresh water tank (B334) is built for onboard potable water storage on boats and watercraft. Measuring 83 1/2" x 18 1/2" x 14 1/4", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended...

    $749.16
    Add to Cart
  • 77 Gallon Marine Water Tank MW-512. Technical drawing of a polyethylene water tank designed for marine vessels.

    77 Gallon Marine Water Tank MW-512

    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 77 Gallon Marine Water Tank, Part# MW-512, is engineered to meet the requirements of mobile...

    MSRP: $625.64
    $594.84
    Add to Cart
  • An image of a 75 Gallon Marine Holding Tank | BOAT61W

    80 Gallon Marine Fresh Water Tank | B458

    This 80-gallon Ronco marine fresh water tank (B458) is built for onboard potable water storage on boats and watercraft. Measuring 62 1/4" x 25 1/4" x 12 5/8", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended...

    $796.37
    Add to Cart
  • An image of a 60 Gallon RV Holding Tank | RV82H

    80 Gallon Marine Fresh Water Tank | B367

    This 80-gallon Ronco marine fresh water tank (B367) is built for onboard potable water storage on boats and watercraft. Measuring 50" x 31" x 18 1/2", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on...

    $995.21
    Add to Cart
  • An image of a 45 Gallon RV Holding Tank | RV87H

    80 Gallon Marine Fresh Water Tank | B363

    This 80-gallon Ronco marine fresh water tank (B363) is built for onboard potable water storage on boats and watercraft. Measuring 39 1/2" x 31 1/2" x 16 3/4", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended...

    $631.67
    Add to Cart
  • An image of a 98 Gallon Marine Holding Tank | B530

    80 Gallon Marine Fresh Water Tank | B327

    This 80-gallon Ronco marine fresh water tank (B327) is built for onboard potable water storage on boats and watercraft. Measuring 48" x 24" x 18", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on the...

    $642.71
    Add to Cart
  • An image of a 58 Gallon RV Fresh Water Tank | RV42W

    80 Gallon Marine Fresh Water Tank | B299

    This 80-gallon Ronco marine fresh water tank (B299) is built for onboard potable water storage on boats and watercraft. Measuring 76" x 28" x 10", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on the...

    $642.71
    Add to Cart
  • An image of a 40 Gallon RV Fresh Water Tank | RVB456

    80 Gallon Marine Fresh Water Tank | B282

    This 80-gallon Ronco marine fresh water tank (B282) is built for onboard potable water storage on boats and watercraft. Measuring 50 7/8" x 20" x 20 7/8", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended...

    $796.37
    Add to Cart
  • An image of a 40 Gallon Marine Fresh Water Tank | B456

    80 Gallon Marine Fresh Water Tank | B260

    This 80-gallon Ronco marine fresh water tank (B260) is built for onboard potable water storage on boats and watercraft. Measuring 45 5/8" x 22" x 20 1/2", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended...

    $642.71
    Add to Cart
  • An image of a 19 Gallon RV Fresh Water Tank | RV27W

    80 Gallon Marine Fresh Water Tank | B230

    This 80-gallon Ronco marine fresh water tank (B230) is built for onboard potable water storage on boats and watercraft. Measuring 68 1/2" x 27" x 11", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on...

    $642.71
    Add to Cart
  • 80 Gallon Marine Water Tank MW-540. Technical drawing of a polyethylene water tank designed for marine vessels.

    80 Gallon Marine Water Tank MW-540

    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 80 Gallon Marine Water Tank, Part# MW-540, is engineered to meet the requirements of mobile...

    MSRP: $547.52
    $520.56
    Add to Cart
  • 80 Gallon Marine Water Tank MW-426. Technical drawing of a polyethylene water tank designed for marine vessels.

    80 Gallon Marine Water Tank MW-426

    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 80 Gallon Marine Water Tank, Part# MW-426, is engineered to meet the requirements of mobile...

    MSRP: $538.89
    $512.35
    Add to Cart
  • 80 Gallon Marine Water Tank MW-251. Technical drawing of a polyethylene water tank designed for marine vessels.

    80 Gallon Marine Water Tank MW-251

    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 80 Gallon Marine Water Tank, Part# MW-251, is engineered to meet the requirements of mobile...

    MSRP: $755.28
    $718.10
    Add to Cart