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

  • 30 Gallon Marine Water Tank MW-338. Technical drawing of a polyethylene water tank designed for marine vessels.

    30 Gallon Marine Water Tank MW-338

    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 30 Gallon Marine Water Tank, Part# MW-338, is engineered to meet the requirements of mobile...

    MSRP: $382.48
    $363.65
    Add to Cart
  • 30 Gallon Marine Water Tank MW-292. Technical drawing of a polyethylene water tank designed for marine vessels.

    30 Gallon Marine Water Tank MW-292

    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 30 Gallon Marine Water Tank, Part# MW-292, is engineered to meet the requirements of mobile...

    MSRP: $306.69
    $291.59
    Add to Cart
  • 30 Gallon Marine Water Tank MW-280. Technical drawing of a polyethylene water tank designed for marine vessels.

    30 Gallon Marine Water Tank MW-280

    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 30 Gallon Marine Water Tank, Part# MW-280, is engineered to meet the requirements of mobile...

    MSRP: $338.16
    $321.51
    Add to Cart
  • 30 Gallon Marine Water Tank MW-254. Technical drawing of a polyethylene water tank designed for marine vessels.

    30 Gallon Marine Water Tank MW-254

    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 30 Gallon Marine Water Tank, Part# MW-254, is engineered to meet the requirements of mobile...

    MSRP: $304.52
    $289.52
    Add to Cart
  • 30 Gallon Marine Water Tank MW-244. Technical drawing of a polyethylene water tank designed for marine vessels.

    30 Gallon Marine Water Tank MW-244

    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 30 Gallon Marine Water Tank, Part# MW-244, is engineered to meet the requirements of mobile...

    MSRP: $314.16
    $298.70
    Add to Cart
  • 30 Gallon Marine Water Tank MW-233. Technical drawing of a polyethylene water tank designed for marine vessels.

    30 Gallon Marine Water Tank MW-233

    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 30 Gallon Marine Water Tank, Part# MW-233, is engineered to meet the requirements of mobile...

    MSRP: $312.26
    $296.89
    Add to Cart
  • An image of a 34 Gallon Marine Holding Tank | B471

    31 Gallon Marine Fresh Water Tank | BOAT26W

    This 31-gallon Ronco marine fresh water tank (BOAT26W) is built for onboard potable water storage on boats and watercraft. Measuring 31" x 23" x 11 1/2", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips...

    $339.43
    Add to Cart
  • 31 Gallon Marine Water Tank MW-529. Technical drawing of a polyethylene water tank designed for marine vessels.

    31 Gallon Marine Water Tank MW-529

    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 31 Gallon Marine Water Tank, Part# MW-529, is engineered to meet the requirements of mobile...

    MSRP: $356.12
    $338.59
    Add to Cart
  • An image of a 95 Gallon Marine Fresh Water Tank | B354

    32 Gallon Marine Fresh Water Tank | BOAT2W

    This 32-gallon Ronco marine fresh water tank (BOAT2W) is built for onboard potable water storage on boats and watercraft. Measuring 37 1/2" x 19" x 12", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips...

    $339.43
    Add to Cart
  • An image of a 32 Gallon Marine Holding Tank | B223

    32 Gallon Marine Fresh Water Tank | B449

    This 32-gallon Ronco marine fresh water tank (B449) is built for onboard potable water storage on boats and watercraft. Measuring 44 1/2" x 15 1/2" x 12 1/2", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended...

    $373.57
    Add to Cart
  • An image of a 6 Gallon RV Fresh Water Tank | RVB357

    32 Gallon Marine Fresh Water Tank | B353

    This 32-gallon Ronco marine fresh water tank (B353) is built for onboard potable water storage on boats and watercraft. Measuring 35 1/2" x 43 3/4" x 9", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips...

    $386.63
    Add to Cart
  • An image of a 29 Gallon Marine Fresh Water Tank | B421

    32 Gallon Marine Fresh Water Tank | B331

    This 32-gallon Ronco marine fresh water tank (B331) is built for onboard potable water storage on boats and watercraft. Measuring 51" x 21" x 8", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on the...

    $386.63
    Add to Cart
  • An image of a 275 Gallon PP Ronco White Cylindrical Open Top Tank | 275PP

    32 Gallon Marine Fresh Water Tank | B316

    This 32-gallon Ronco marine fresh water tank (B316) is built for onboard potable water storage on boats and watercraft. Measuring 69" x 11" x 11", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on the...

    $373.57
    Add to Cart
  • An image of a 10 Gallon Marine Holding Tank | B438

    32 Gallon Marine Fresh Water Tank | B258

    This 32-gallon Ronco marine fresh water tank (B258) is built for onboard potable water storage on boats and watercraft. Measuring 22" x 22" x 20", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on the...

    $386.63
    Add to Cart
  • An image of a 15 Gallon Marine Holding Tank | B388

    32 Gallon Marine Fresh Water Tank | B223

    This 32-gallon Ronco marine fresh water tank (B223) is built for onboard potable water storage on boats and watercraft. Measuring 39" x 20" x 22 1/2", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on...

    $421.77
    Add to Cart
  • An image of a 17 Gallon Marine Holding Tank | BOAT20W

    32 Gallon Marine Fresh Water Tank | B143

    This 32-gallon Ronco marine fresh water tank (B143) is built for onboard potable water storage on boats and watercraft. Measuring 36" x 24 1/2" x 17", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on...

    $386.63
    Add to Cart
  • An image of a 50 Gallon Marine Holding Tank | B210

    32 Gallon Marine Fresh Water Tank | B141

    This 32-gallon Ronco marine fresh water tank (B141) is built for onboard potable water storage on boats and watercraft. Measuring 56" x 15" x 12 1/2", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on...

    $386.63
    Add to Cart
  • An image of a 105 Gallon Marine Holding Tank | B261

    32 Gallon Marine Fresh Water Tank | B127

    This 32-gallon Ronco marine fresh water tank (B127) is built for onboard potable water storage on boats and watercraft. Measuring 30" x 16 1/2" x 16", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on...

    $350.48
    Add to Cart
  • 32 Gallon Marine Water Tank MW-524. Technical drawing of a polyethylene water tank designed for marine vessels.

    32 Gallon Marine Water Tank MW-524

    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 32 Gallon Marine Water Tank, Part# MW-524, is engineered to meet the requirements of mobile...

    MSRP: $284.18
    $270.19
    Add to Cart
  • 32 Gallon Marine Water Tank MW-421. Technical drawing of a polyethylene water tank designed for marine vessels.

    32 Gallon Marine Water Tank MW-421

    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 32 Gallon Marine Water Tank, Part# MW-421, is engineered to meet the requirements of mobile...

    MSRP: $311.72
    $296.37
    Add to Cart
  • 32 Gallon Marine Water Tank MW-373. Technical drawing of a polyethylene water tank designed for marine vessels.

    32 Gallon Marine Water Tank MW-373

    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 32 Gallon Marine Water Tank, Part# MW-373, is engineered to meet the requirements of mobile...

    MSRP: $506.62
    $481.68
    Add to Cart
  • 32 Gallon Marine Water Tank MW-32. Technical drawing of a polyethylene water tank designed for marine vessels.

    32 Gallon Marine Water Tank MW-32

    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 32 Gallon Marine Water Tank, Part# MW-32, is engineered to meet the requirements of mobile...

    MSRP: $397.76
    $378.17
    Add to Cart
  • 32 Gallon Marine Water Tank MW-236. Technical drawing of a polyethylene water tank designed for marine vessels.

    32 Gallon Marine Water Tank MW-236

    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 32 Gallon Marine Water Tank, Part# MW-236, is engineered to meet the requirements of mobile...

    MSRP: $391.27
    $372.01
    Add to Cart
  • An image of a 65 Gallon Marine Holding Tank | B248

    33 Gallon Marine Fresh Water Tank | BOAT53W

    This 33-gallon Ronco marine fresh water tank (BOAT53W) is built for onboard potable water storage on boats and watercraft. Measuring 70" x 16" x 8", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on...

    $386.63
    Add to Cart
  • An image of a 54 Gallon Marine Fresh Water Tank | B472

    33 Gallon Marine Fresh Water Tank | B479

    This 33-gallon Ronco marine fresh water tank (B479) is built for onboard potable water storage on boats and watercraft. Measuring 26" x 23" x 16", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on the...

    $386.63
    Add to Cart
  • An image of a 125 Gallon RV Fresh Water Tank | B247

    33 Gallon Marine Fresh Water Tank | B409

    This 33-gallon Ronco marine fresh water tank (B409) is built for onboard potable water storage on boats and watercraft. Measuring 70" x 16" x 8", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on the...

    $350.48
    Add to Cart
  • An image of a 65 Gallon Marine Holding Tank | B324

    33 Gallon Marine Fresh Water Tank | B397

    This 33-gallon Ronco marine fresh water tank (B397) is built for onboard potable water storage on boats and watercraft. Measuring 44" x 18" x 14", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on the...

    $432.83
    Add to Cart