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 63 Gallon PE Ronco White Rectangular Open Top Tank | 30X18X30PE

    8 Gallon Marine Fresh Water Tank | B186

    This 8-gallon Ronco marine fresh water tank (B186) is built for onboard potable water storage on boats and watercraft. Measuring 18" x 11 1/2" x 10", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on...

    $197.83
    Add to Cart
  • An image of a 7 Gallon PP Ronco White Rectangular Open Top Tank | 12X12X12PP

    8 Gallon Marine Fresh Water Tank | B121

    This 8-gallon Ronco marine fresh water tank (B121) is built for onboard potable water storage on boats and watercraft. Measuring 32 1/4" x 6 1/2" x 10 1/2", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended...

    $187.79
    Add to Cart
  • An image of a 20 Gallon PE Ronco White Rectangular Open Top Tank | 24X12X18PE

    9 Gallon Marine Fresh Water Tank | BOAT23W

    This 9-gallon Ronco marine fresh water tank (BOAT23W) is built for onboard potable water storage on boats and watercraft. Measuring 30 1/4" x 10" x 9", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips...

    $210.88
    Add to Cart
  • An image of a 7 Gallon Marine Holding Tank | B271

    9 Gallon Marine Fresh Water Tank | B532

    This 9-gallon Ronco marine fresh water tank (B532) is built for onboard potable water storage on boats and watercraft. Measuring 18 1/2" x 17" x 7 1/2", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips...

    $197.83
    Add to Cart
  • An image of a 45 Gallon Marine Holding Tank | B197

    9 Gallon Marine Fresh Water Tank | B442

    This 9-gallon Ronco marine fresh water tank (B442) is built for onboard potable water storage on boats and watercraft. Measuring 19" x 15" x 9", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on the...

    $197.83
    Add to Cart
  • An image of a 50 Gallon PP Ronco White Rectangular Open Top Tank | 24X18X30PP

    9 Gallon Marine Fresh Water Tank | B361

    This 9-gallon Ronco marine fresh water tank (B361) is built for onboard potable water storage on boats and watercraft. Measuring 25 1/2" x 10 1/2" x 8 1/2", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended...

    $197.83
    Add to Cart
  • An image of a 36 Gallon Marine Holding Tank | B158

    9 Gallon Marine Fresh Water Tank | B358

    This 9-gallon Ronco marine fresh water tank (B358) is built for onboard potable water storage on boats and watercraft. Measuring 19 1/2" x 14" x 8", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on...

    $197.83
    Add to Cart
  • An image of a 50 Gallon PE Ronco White Rectangular Open Top Tank | 24X18X30PE

    9 Gallon Marine Fresh Water Tank | B341

    This 9-gallon Ronco marine fresh water tank (B341) is built for onboard potable water storage on boats and watercraft. Measuring 31" x 10 1/2" x 7", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on...

    $187.79
    Add to Cart
  • An image of a 8 Gallon Marine Fresh Water Tank | B186

    9 Gallon Marine Fresh Water Tank | B336

    This 9-gallon Ronco marine fresh water tank (B336) is built for onboard potable water storage on boats and watercraft. Measuring 25" x 14 5/8" x 6", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on...

    $187.79
    Add to Cart
  • An image of a 100 Gallon Ronco White Low Profile Transport Tank | AD9410LD

    9 Gallon Marine Fresh Water Tank | B321

    This 9-gallon Ronco marine fresh water tank (B321) is built for onboard potable water storage on boats and watercraft. Measuring 18" x 12 1/2" x 11", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on...

    $197.83
    Add to Cart
  • An image of a 45 Gallon Marine Fresh Water Tank | B197

    9 Gallon Marine Fresh Water Tank | B304

    This 9-gallon Ronco marine fresh water tank (B304) is built for onboard potable water storage on boats and watercraft. Measuring 27" x 15" x 6", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on the...

    $197.83
    Add to Cart
  • An image of a 20 Gallon Marine Fresh Water Tank | B196

    9 Gallon Marine Fresh Water Tank | B288

    This 9-gallon Ronco marine fresh water tank (B288) is built for onboard potable water storage on boats and watercraft. Measuring 32" x 15" x 5", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on the...

    $197.83
    Add to Cart
  • An image of a 30 Gallon Marine Fresh Water Tank | B157

    9 Gallon Marine Fresh Water Tank | B132

    This 9-gallon Ronco marine fresh water tank (B132) is built for onboard potable water storage on boats and watercraft. Measuring 16" x 14" x 10", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on the...

    $209.88
    Add to Cart
  • An image of a 41 Gallon PE Ronco White Rectangular Open Top Tank | 36X24X12PE

    10 Gallon Marine Fresh Water Tank | B560

    This 10-gallon Ronco marine fresh water tank (B560) is built for onboard potable water storage on boats and watercraft. Measuring 18" x 12" x 12", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on the...

    $209.88
    Add to Cart
  • An image of a 7 Gallon Marine Fresh Water Tank | B272

    10 Gallon Marine Fresh Water Tank | B495

    This 10-gallon Ronco marine fresh water tank (B495) is built for onboard potable water storage on boats and watercraft. Measuring 18" x 17" x 11 1/2", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on...

    $269.13
    Add to Cart
  • An image of a 110 Gallon PE Ronco White Rectangular Open Top Tank | 24X24X48PE

    10 Gallon Marine Fresh Water Tank | B438

    This 10-gallon Ronco marine fresh water tank (B438) is built for onboard potable water storage on boats and watercraft. Measuring 26" x 11" x 11", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on the...

    $197.83
    Add to Cart
  • An image of a 21 Gallon Marine Holding Tank | B110

    10 Gallon Marine Fresh Water Tank | B389

    This 10-gallon Ronco marine fresh water tank (B389) is built for onboard potable water storage on boats and watercraft. Measuring 25 1/4" x 12 3/4" x 8", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips...

    $209.88
    Add to Cart
  • An image of a 13 Gallon Marine Holding Tank | B102

    10 Gallon Marine Fresh Water Tank | B365

    This 10-gallon Ronco marine fresh water tank (B365) is built for onboard potable water storage on boats and watercraft. Measuring 17 3/4" x 12 1/2" x 11", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended...

    $209.88
    Add to Cart
  • An image of a 8 Gallon Marine Fresh Water Tank | B360

    10 Gallon Marine Fresh Water Tank | B323

    This 10-gallon Ronco marine fresh water tank (B323) is built for onboard potable water storage on boats and watercraft. Measuring 32" x 19 1/2" x 4 3/4", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips...

    $209.88
    Add to Cart
  • An image of a 25 Gallon RV Fresh Water Tank | RVB408

    10 Gallon Marine Fresh Water Tank | B290

    This 10-gallon Ronco marine fresh water tank (B290) is built for onboard potable water storage on boats and watercraft. Measuring 20" x 15" x 14", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on the...

    $269.13
    Add to Cart
  • An image of a 16 Gallon Marine Holding Tank | B106

    10 Gallon Marine Fresh Water Tank | B278

    This 10-gallon Ronco marine fresh water tank (B278) is built for onboard potable water storage on boats and watercraft. Measuring 24" x 12 5/8" x 9 1/8", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips...

    $233.99
    Add to Cart
  • An image of a 22 Gallon Marine Fresh Water Tank | B134

    10 Gallon Marine Fresh Water Tank | B263

    This 10-gallon Ronco marine fresh water tank (B263) is built for onboard potable water storage on boats and watercraft. Measuring 15 3/8" x 13 1/4" x 13 1/4", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended...

    $197.83
    Add to Cart
  • An image of a 27 Gallon PE Ronco White Rectangular Open Top Tank | 24X12X24PE

    10 Gallon Marine Fresh Water Tank | B217

    This 10-gallon Ronco marine fresh water tank (B217) is built for onboard potable water storage on boats and watercraft. Measuring 36" x 10" x 10", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on the...

    $210.88
    Add to Cart
  • 10 Gallon Marine Water Tank MW-53. Technical drawing of a polyethylene water tank designed for marine vessels.

    10 Gallon Marine Water Tank MW-53

    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 10 Gallon Marine Water Tank, Part# MW-53, is engineered to meet the requirements of mobile...

    MSRP: $182.89
    $173.88
    Add to Cart
  • 10 Gallon Marine Water Tank MW-490. Technical drawing of a polyethylene water tank designed for marine vessels.

    10 Gallon Marine Water Tank MW-490

    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 10 Gallon Marine Water Tank, Part# MW-490, is engineered to meet the requirements of mobile...

    MSRP: $220.52
    $209.67
    Add to Cart
  • 10 Gallon Marine Water Tank MW-431. Technical drawing of a polyethylene water tank designed for marine vessels.

    10 Gallon Marine Water Tank MW-431

    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 10 Gallon Marine Water Tank, Part# MW-431, is engineered to meet the requirements of mobile...

    MSRP: $242.87
    $230.92
    Add to Cart
  • 10 Gallon Marine Water Tank MW-358. Technical drawing of a polyethylene water tank designed for marine vessels.

    10 Gallon Marine Water Tank MW-358

    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 10 Gallon Marine Water Tank, Part# MW-358, is engineered to meet the requirements of mobile...

    MSRP: $174.36
    $165.77
    Add to Cart
  • 10 Gallon Marine Water Tank MW-33. Technical drawing of a polyethylene water tank designed for marine vessels.

    10 Gallon Marine Water Tank MW-33

    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 10 Gallon Marine Water Tank, Part# MW-33, is engineered to meet the requirements of mobile...

    MSRP: $221.11
    $210.23
    Add to Cart
  • An image of a 35 Gallon Marine Fresh Water Tank | B116

    11 Gallon Marine Fresh Water Tank | BOAT16W

    This 11-gallon Ronco marine fresh water tank (BOAT16W) is built for onboard potable water storage on boats and watercraft. Measuring 18" x 13" x 13", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on...

    $233.99
    Add to Cart
  • An image of a 21 Gallon Marine Fresh Water Tank | B219

    11 Gallon Marine Fresh Water Tank | BOAT14W

    This 11-gallon Ronco marine fresh water tank (BOAT14W) is built for onboard potable water storage on boats and watercraft. Measuring 24" x 15 1/2" x 8 1/4", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended...

    $233.99
    Add to Cart
  • An image of a 18 Gallon Marine Holding Tank | B235

    11 Gallon Marine Fresh Water Tank | B375

    This 11-gallon Ronco marine fresh water tank (B375) is built for onboard potable water storage on boats and watercraft. Measuring 17" x 16" x 11", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on the...

    $232.98
    Add to Cart