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 53 Gallon RV Fresh Water Tank | RVB312

    100 Gallon Marine Fresh Water Tank | B400

    This 100-gallon Ronco marine fresh water tank (B400) is built for onboard potable water storage on boats and watercraft. Measuring 52" x 37" x 14", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on...

    $912.86
    Add to Cart
  • An image of a 45 Gallon RV Fresh Water Tank | RVB310

    100 Gallon Marine Fresh Water Tank | B313

    This 100-gallon Ronco marine fresh water tank (B313) is built for onboard potable water storage on boats and watercraft. Measuring 48" x 37" x 20", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on...

    $1,065.50
    Add to Cart
  • An image of a 27 Gallon Marine Fresh Water Tank | BOAT24W

    100 Gallon Marine Fresh Water Tank | B249

    This 100-gallon Ronco marine fresh water tank (B249) is built for onboard potable water storage on boats and watercraft. Measuring 50 1/4" x 24 1/2" x 20 7/8", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended...

    $761.21
    Add to Cart
  • 100 Gallon Marine Water Tank MW-462. Technical drawing of a polyethylene water tank designed for marine vessels.

    100 Gallon Marine Water Tank MW-462

    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 100 Gallon Marine Water Tank, Part# MW-462, is engineered to meet the requirements of mobile...

    MSRP: $783.59
    $745.01
    Add to Cart
  • 100 Gallon Marine Water Tank MW-348. Technical drawing of a polyethylene water tank designed for marine vessels.

    100 Gallon Marine Water Tank MW-348

    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 100 Gallon Marine Water Tank, Part# MW-348, is engineered to meet the requirements of mobile...

    MSRP: $740.91
    $704.44
    Add to Cart
  • 100 Gallon Marine Water Tank MW-325. Technical drawing of a polyethylene water tank designed for marine vessels.

    100 Gallon Marine Water Tank MW-325

    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 100 Gallon Marine Water Tank, Part# MW-325, is engineered to meet the requirements of mobile...

    MSRP: $756.28
    $719.05
    Add to Cart
  • 100 Gallon Marine Water Tank MW-229. Technical drawing of a polyethylene water tank designed for marine vessels.

    100 Gallon Marine Water Tank MW-229

    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 100 Gallon Marine Water Tank, Part# MW-229, is engineered to meet the requirements of mobile...

    MSRP: $804.05
    $764.47
    Add to Cart
  • 100 Gallon Marine Water Tank MW-221. Technical drawing of a polyethylene water tank designed for marine vessels.

    100 Gallon Marine Water Tank MW-221

    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 100 Gallon Marine Water Tank, Part# MW-221, is engineered to meet the requirements of mobile...

    MSRP: $492.00
    $467.77
    Add to Cart
  • 100 Gallon Marine Water Tank MW-215. Technical drawing of a polyethylene water tank designed for marine vessels.

    100 Gallon Marine Water Tank MW-215

    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 100 Gallon Marine Water Tank, Part# MW-215, is engineered to meet the requirements of mobile...

    MSRP: $741.66
    $705.15
    Add to Cart
  • 100 Gallon Marine Water Tank MW-101. Technical drawing of a polyethylene water tank designed for marine vessels.

    100 Gallon Marine Water Tank MW-101

    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 100 Gallon Marine Water Tank, Part# MW-101, is engineered to meet the requirements of mobile...

    MSRP: $631.62
    $600.52
    Add to Cart
  • An image of a 20 Gallon RV Holding Tank | RV102H

    105 Gallon Marine Fresh Water Tank | B427

    This 105-gallon Ronco marine fresh water tank (B427) is built for onboard potable water storage on boats and watercraft. Measuring 39" x 26" x 26", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on...

    $689.91
    Add to Cart
  • An image of a 8 Gallon RV Fresh Water Tank | RVB360

    105 Gallon Marine Fresh Water Tank | B261

    This 105-gallon Ronco marine fresh water tank (B261) is built for onboard potable water storage on boats and watercraft. Measuring 45" x 45" x 22 1/8", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips...

    $876.71
    Add to Cart
  • 106 Gallon Marine Water Tank MW-63. Technical drawing of a polyethylene water tank designed for marine vessels.

    106 Gallon Marine Water Tank MW-63

    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 106 Gallon Marine Water Tank, Part# MW-63, is engineered to meet the requirements of mobile...

    MSRP: $758.52
    $721.18
    Add to Cart
  • An image of a 31 Gallon Marine Fresh Water Tank | BOAT26W

    110 Gallon Marine Fresh Water Tank | B433

    This 110-gallon Ronco marine fresh water tank (B433) is built for onboard potable water storage on boats and watercraft. Measuring 48" x 24 1/2" x 24", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips...

    $725.06
    Add to Cart
  • An image of a 25 Gallon RV Fresh Water Tank | RVB225

    110 Gallon Marine Fresh Water Tank | B391

    This 110-gallon Ronco marine fresh water tank (B391) is built for onboard potable water storage on boats and watercraft. Measuring 95" x 33" x 9", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on the...

    $701.97
    Add to Cart
  • An image of a 53 Gallon Marine Fresh Water Tank | B545

    110 Gallon Marine Fresh Water Tank | B298

    This 110-gallon Ronco marine fresh water tank (B298) is built for onboard potable water storage on boats and watercraft. Measuring 76" x 24" x 15 1/2", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips...

    $701.97
    Add to Cart
  • An image of a 10 Gallon RV Holding Tank | RV34H

    115 Gallon Marine Fresh Water Tank | B466

    This 115-gallon Ronco marine fresh water tank (B466) is built for onboard potable water storage on boats and watercraft. Measuring 54" x 27" x 20", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on...

    $748.16
    Add to Cart
  • An image of a 12 Gallon RV Holding Tank | RV44H

    115 Gallon Marine Fresh Water Tank | B328

    This 115-gallon Ronco marine fresh water tank (B328) is built for onboard potable water storage on boats and watercraft. Measuring 39 1/2" x 28" x 26", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips...

    $748.16
    Add to Cart
  • 120 Gallon Marine Water Tank MW-437. Technical drawing of a polyethylene water tank designed for marine vessels.

    120 Gallon Marine Water Tank MW-437

    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 120 Gallon Marine Water Tank, Part# MW-437, is engineered to meet the requirements of mobile...

    MSRP: $2,176.46
    $2,069.31
    Add to Cart
  • An image of a 20 Gallon RV Fresh Water Tank | RV57W

    125 Gallon Marine Fresh Water Tank | B247

    This 125-gallon Ronco marine fresh water tank (B247) is built for onboard potable water storage on boats and watercraft. Measuring 43 1/8" x 29 7/8" x 24", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended...

    $865.65
    Add to Cart
  • An image of a 18 Gallon RV Holding Tank | RV69H

    125 Gallon Marine Fresh Water Tank | B243

    This 125-gallon Ronco marine fresh water tank (B243) is built for onboard potable water storage on boats and watercraft. Measuring 53 1/2" x 30" x 19 1/2", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended...

    $912.86
    Add to Cart
  • 125 Gallon Marine Water Tank MW-547. Technical drawing of a polyethylene water tank designed for marine vessels.

    125 Gallon Marine Water Tank MW-547

    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 125 Gallon Marine Water Tank, Part# MW-547, is engineered to meet the requirements of mobile...

    MSRP: $757.52
    $720.23
    Add to Cart
  • 125 Gallon Marine Water Tank MW-238. Technical drawing of a polyethylene water tank designed for marine vessels.

    125 Gallon Marine Water Tank MW-238

    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 125 Gallon Marine Water Tank, Part# MW-238, is engineered to meet the requirements of mobile...

    MSRP: $1,136.80
    $1,080.83
    Add to Cart
  • An image of a 8 Gallon RV Fresh Water Tank | RVB270

    130 Gallon Marine Fresh Water Tank | B467

    This 130-gallon Ronco marine fresh water tank (B467) is built for onboard potable water storage on boats and watercraft. Measuring 41 1/2" x 35 3/4" x 27", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended...

    $900.81
    Add to Cart
  • An image of a 27 Gallon RV Holding Tank | RV6H

    130 Gallon Marine Fresh Water Tank | B356

    This 130-gallon Ronco marine fresh water tank (B356) is built for onboard potable water storage on boats and watercraft. Measuring 60" x 30" x 18", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on...

    $865.65
    Add to Cart
  • 130 Gallon Marine Water Tank MW-450. Technical drawing of a polyethylene water tank designed for marine vessels.

    130 Gallon Marine Water Tank MW-450

    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 130 Gallon Marine Water Tank, Part# MW-450, is engineered to meet the requirements of mobile...

    MSRP: $1,226.50
    $1,166.11
    Add to Cart
  • 132 Gallon Marine Water Tank MW-347. Technical drawing of a polyethylene water tank designed for marine vessels.

    132 Gallon Marine Water Tank MW-347

    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 132 Gallon Marine Water Tank, Part# MW-347, is engineered to meet the requirements of mobile...

    MSRP: $1,108.34
    $1,053.77
    Add to Cart