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

  • 60 Gallon Marine Water Tank MW-59. Technical drawing of a polyethylene water tank designed for marine vessels.

    60 Gallon Marine Water Tank MW-59

    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 60 Gallon Marine Water Tank, Part# MW-59, is engineered to meet the requirements of mobile...

    MSRP: $572.14
    $543.97
    Add to Cart
  • 60 Gallon Marine Water Tank MW-331. Technical drawing of a polyethylene water tank designed for marine vessels.

    60 Gallon Marine Water Tank MW-331

    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 60 Gallon Marine Water Tank, Part# MW-331, is engineered to meet the requirements of mobile...

    MSRP: $510.98
    $485.82
    Add to Cart
  • 60 Gallon Marine Water Tank MW-300. Technical drawing of a polyethylene water tank designed for marine vessels.

    60 Gallon Marine Water Tank MW-300

    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 60 Gallon Marine Water Tank, Part# MW-300, is engineered to meet the requirements of mobile...

    MSRP: $448.62
    $426.53
    Add to Cart
  • 60 Gallon Marine Water Tank MW-277. Technical drawing of a polyethylene water tank designed for marine vessels.

    60 Gallon Marine Water Tank MW-277

    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 60 Gallon Marine Water Tank, Part# MW-277, is engineered to meet the requirements of mobile...

    MSRP: $526.05
    $500.16
    Add to Cart
  • 60 Gallon Marine Water Tank MW-276. Technical drawing of a polyethylene water tank designed for marine vessels.

    60 Gallon Marine Water Tank MW-276

    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 60 Gallon Marine Water Tank, Part# MW-276, is engineered to meet the requirements of mobile...

    MSRP: $470.01
    $446.88
    Add to Cart
  • An image of a 14 Gallon RV Fresh Water Tank | RV37W

    62 Gallon Marine Fresh Water Tank | B244

    This 62-gallon Ronco marine fresh water tank (B244) is built for onboard potable water storage on boats and watercraft. Measuring 30" x 27 1/2" x 18 7/8", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended...

    $515.18
    Add to Cart
  • 62 Gallon Marine Water Tank MW-542. Technical drawing of a polyethylene water tank designed for marine vessels.

    62 Gallon Marine Water Tank MW-542

    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 62 Gallon Marine Water Tank, Part# MW-542, is engineered to meet the requirements of mobile...

    MSRP: $891.31
    $847.43
    Add to Cart
  • An image of a 92 Gallon Marine Fresh Water Tank | B483

    64 Gallon Marine Fresh Water Tank | B307

    This 64-gallon Ronco marine fresh water tank (B307) is built for onboard potable water storage on boats and watercraft. Measuring 45" x 23" x 15 3/4", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on...

    $538.27
    Add to Cart
  • 64 Gallon Marine Water Tank MW-536. Technical drawing of a polyethylene water tank designed for marine vessels.

    64 Gallon Marine Water Tank MW-536

    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 64 Gallon Marine Water Tank, Part# MW-536, is engineered to meet the requirements of mobile...

    MSRP: $732.37
    $696.31
    Add to Cart
  • An image of a 27 Gallon RV Holding Tank | RV64H

    65 Gallon Marine Fresh Water Tank | B324

    This 65-gallon Ronco marine fresh water tank (B324) is built for onboard potable water storage on boats and watercraft. Measuring 37" x 30" x 15", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on the...

    $572.41
    Add to Cart
  • An image of a 28 Gallon Marine Fresh Water Tank | BOAT52W

    65 Gallon Marine Fresh Water Tank | B297

    This 65-gallon Ronco marine fresh water tank (B297) is built for onboard potable water storage on boats and watercraft. Measuring 28" x 25" x 24", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on the...

    $550.32
    Add to Cart
  • An image of a 141 Gallon Marine Holding Tank | B484

    65 Gallon Marine Fresh Water Tank | B292

    This 65-gallon Ronco marine fresh water tank (B292) is built for onboard potable water storage on boats and watercraft. Measuring 48" x 23" x 15 1/2", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on...

    $597.52
    Add to Cart
  • An image of a 160/205 Gallon Double Wall Tank | RONCO160205DC

    65 Gallon Marine Fresh Water Tank | B289

    This 65-gallon Ronco marine fresh water tank (B289) is built for onboard potable water storage on boats and watercraft. Measuring 33 1/8" x 26" x 21 3/4", 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 42 Gallon RV Holding Tank | RV74H

    65 Gallon Marine Fresh Water Tank | B283

    This 65-gallon Ronco marine fresh water tank (B283) is built for onboard potable water storage on boats and watercraft. Measuring 39 1/8" x 30 7/8" x 13 1/2", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended...

    $549.32
    Add to Cart
  • An image of a 16 Gallon Marine Holding Tank | B399

    65 Gallon Marine Fresh Water Tank | B248

    This 65-gallon Ronco marine fresh water tank (B248) is built for onboard potable water storage on boats and watercraft. Measuring 48" x 20" x 17", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on the...

    $549.32
    Add to Cart
  • 65 Gallon Marine Water Tank MW-362. Technical drawing of a polyethylene water tank designed for marine vessels.

    65 Gallon Marine Water Tank MW-362

    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 65 Gallon Marine Water Tank, Part# MW-362, is engineered to meet the requirements of mobile...

    MSRP: $421.55
    $400.79
    Add to Cart
  • 65 Gallon Marine Water Tank MW-241. Technical drawing of a polyethylene water tank designed for marine vessels.

    65 Gallon Marine Water Tank MW-241

    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 65 Gallon Marine Water Tank, Part# MW-241, is engineered to meet the requirements of mobile...

    MSRP: $513.00
    $487.75
    Add to Cart
  • 65 Gallon Marine Water Tank MW-220. Technical drawing of a polyethylene water tank designed for marine vessels.

    65 Gallon Marine Water Tank MW-220

    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 65 Gallon Marine Water Tank, Part# MW-220, is engineered to meet the requirements of mobile...

    MSRP: $519.78
    $494.19
    Add to Cart
  • 66 Gallon Marine Water Tank MW-334. Technical drawing of a polyethylene water tank designed for marine vessels.

    66 Gallon Marine Water Tank MW-334

    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 66 Gallon Marine Water Tank, Part# MW-334, is engineered to meet the requirements of mobile...

    MSRP: $497.26
    $472.78
    Add to Cart
  • 67 Gallon Marine Water Tank MW-448. Technical drawing of a polyethylene water tank designed for marine vessels.

    67 Gallon Marine Water Tank MW-448

    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 67 Gallon Marine Water Tank, Part# MW-448, is engineered to meet the requirements of mobile...

    MSRP: $604.00
    $574.27
    Add to Cart
  • 68 Gallon Marine Water Tank MW-463. Technical drawing of a polyethylene water tank designed for marine vessels.

    68 Gallon Marine Water Tank MW-463

    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 68 Gallon Marine Water Tank, Part# MW-463, is engineered to meet the requirements of mobile...

    MSRP: $419.78
    $399.11
    Add to Cart
  • An image of a 65/90 Gallon Double Wall Tank | RONCO6590DC

    69 Gallon Marine Fresh Water Tank | B444

    This 69-gallon Ronco marine fresh water tank (B444) is built for onboard potable water storage on boats and watercraft. Measuring 38" x 26" x 18", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on the...

    $584.46
    Add to Cart
  • An image of a 100 Gallon Ronco White Vertical Storage Tank | RPV100

    69 Gallon Marine Fresh Water Tank | B434

    This 69-gallon Ronco marine fresh water tank (B434) is built for onboard potable water storage on boats and watercraft. Measuring 26" x 26" x 26", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on the...

    $584.46
    Add to Cart
  • An image of a 76 Gallon RV Fresh Water Tank | RV65W

    70 Gallon Marine Fresh Water Tank | B401

    This 70-gallon Ronco marine fresh water tank (B401) is built for onboard potable water storage on boats and watercraft. Measuring 34" x 30" x 18", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on the...

    $607.57
    Add to Cart
  • An image of a 32 Gallon RV Fresh Water Tank | RVB127

    70 Gallon Marine Fresh Water Tank | B343

    This 70-gallon Ronco marine fresh water tank (B343) is built for onboard potable water storage on boats and watercraft. Measuring 46" x 32" x 17 7/8", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on...

    $667.82
    Add to Cart
  • An image of a 141 Gallon RV Fresh Water Tank | B484

    70 Gallon Marine Fresh Water Tank | B296

    This 70-gallon Ronco marine fresh water tank (B296) is built for onboard potable water storage on boats and watercraft. Measuring 34" x 23" x 23", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on the...

    $584.46
    Add to Cart
  • An image of a 100 Gallon Marine Fresh Water Tank | B400

    70 Gallon Marine Fresh Water Tank | B209

    This 70-gallon Ronco marine fresh water tank (B209) is built for onboard potable water storage on boats and watercraft. Measuring 75 1/4" x 20" x 14 7/8", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended...

    $936.96
    Add to Cart
  • An image of a 12 Gallon RV Fresh Water Tank | RVB124

    70 Gallon Marine Fresh Water Tank | B208

    This 70-gallon Ronco marine fresh water tank (B208) is built for onboard potable water storage on boats and watercraft. Measuring 75" x 32" x 14 1/2", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on...

    $936.96
    Add to Cart