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

  • 2 Gallon Marine Water Tank MW-364

    2 Gallon Marine Water Tank MW-364

    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 2 Gallon Marine Water Tank, Part# MW-364, is engineered to meet the requirements of mobile...

    MSRP: $81.40
    $77.39
    Add to Cart
  • An image of a 14 Gallon PE Ronco White Rectangular Open Top Tank | 12X12X24PE

    3 Gallon Marine Fresh Water Tank | BOAT13W

    This 3-gallon Ronco marine fresh water tank (BOAT13W) is built for onboard potable water storage on boats and watercraft. Measuring 17" x 7" x 7", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on the...

    $128.53
    Add to Cart
  • An image of a 16 Gallon PE Ronco White Rectangular Open Top Tank | 18X12X18PE

    3 Gallon Marine Fresh Water Tank | B267

    This 3-gallon Ronco marine fresh water tank (B267) is built for onboard potable water storage on boats and watercraft. Measuring 16 3/8" x 9" x 5 1/4", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips...

    $139.59
    Add to Cart
  • An image of a 54 Gallon PP Ronco White Rectangular Open Top Tank | 24X24X24PP

    4 Gallon Marine Fresh Water Tank | B525

    This 4-gallon Ronco marine fresh water tank (B525) is built for onboard potable water storage on boats and watercraft. Measuring 26" x 11" x 7", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on the...

    $151.64
    Add to Cart
  • An image of a 150 Gallon PP Ronco White Cylindrical Open Top Tank | 150PP

    4 Gallon Marine Fresh Water Tank | B269

    This 4-gallon Ronco marine fresh water tank (B269) is built for onboard potable water storage on boats and watercraft. Measuring 7 5/8" x 8 1/4" x 7 7/8", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended...

    $139.59
    Add to Cart
  • An image of a 23 Gallon Marine Holding Tank | B142

    5 Gallon Marine Fresh Water Tank | B410

    This 5-gallon Ronco marine fresh water tank (B410) is built for onboard potable water storage on boats and watercraft. Measuring 18" x 13 1/2" x 7", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on...

    $151.64
    Add to Cart
  • An image of a 86 Gallon PE Ronco White Rectangular Open Top Tank | 30X24X30PE

    5 Gallon Marine Fresh Water Tank | B390

    This 5-gallon Ronco marine fresh water tank (B390) is built for onboard potable water storage on boats and watercraft. Measuring 20" x 12" x 5 1/2", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on...

    $151.64
    Add to Cart
  • An image of a 12 Gallon PP Ronco White Rectangular Open Top Tank | 18X14X12PP

    5 Gallon Marine Fresh Water Tank | B377

    This 5-gallon Ronco marine fresh water tank (B377) is built for onboard potable water storage on boats and watercraft. Measuring 18 1/2" x 9 1/2" x 6 3/4", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended...

    $151.64
    Add to Cart
  • An image of a 17 Gallon PE Ronco White Cylindrical Open Top Tank | 17LDPE

    5 Gallon Marine Fresh Water Tank | B322

    This 5-gallon Ronco marine fresh water tank (B322) is built for onboard potable water storage on boats and watercraft. Measuring 21" x 8 1/4" x 8", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on...

    $151.64
    Add to Cart
  • An image of a 86 Gallon PP Ronco White Rectangular Open Top Tank | 30X24X28PP

    5 Gallon Marine Fresh Water Tank | B303

    This 5-gallon Ronco marine fresh water tank (B303) is built for onboard potable water storage on boats and watercraft. Measuring 24" x 12" x 5", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on the...

    $152.64
    Add to Cart
  • An image of a 65 Gallon PE Ronco White Cylindrical Open Top Tank | 65LDPE

    5 Gallon Marine Fresh Water Tank | B268

    This 5-gallon Ronco marine fresh water tank (B268) is built for onboard potable water storage on boats and watercraft. Measuring 12 1/4" x 12 1/4" x 8 1/4", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended...

    $139.59
    Add to Cart
  • An image of a 53 Gallon Marine Holding Tank | B133

    6 Gallon Marine Fresh Water Tank | B533

    This 6-gallon Ronco marine fresh water tank (B533) is built for onboard potable water storage on boats and watercraft. Measuring 27" x 13 1/4" x 4 1/4", 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 35 Gallon Marine Fresh Water Tank | B147

    6 Gallon Marine Fresh Water Tank | B404

    This 6-gallon Ronco marine fresh water tank (B404) is built for onboard potable water storage on boats and watercraft. Measuring 13 3/4" x 13 3/4" x 10", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips...

    $174.73
    Add to Cart
  • An image of a 58 Gallon PP Ronco White Rectangular Open Top Tank | 30X12X42PP

    6 Gallon Marine Fresh Water Tank | B357

    This 6-gallon Ronco marine fresh water tank (B357) is built for onboard potable water storage on boats and watercraft. Measuring 20" x 11 1/2" x 7", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on...

    $174.73
    Add to Cart
  • An image of a 45 Gallon Marine Fresh Water Tank | B176

    6 Gallon Marine Fresh Water Tank | B285

    This 6-gallon Ronco marine fresh water tank (B285) is built for onboard potable water storage on boats and watercraft. Measuring 21 5/8" x 14 3/8" x 5 3/8", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended...

    $174.73
    Add to Cart
  • An image of a 103 Gallon PP Ronco White Rectangular Open Top Tank | 30X24X36PP

    6 Gallon Marine Fresh Water Tank | B277

    This 6-gallon Ronco marine fresh water tank (B277) is built for onboard potable water storage on boats and watercraft. Measuring 16" x 12" x 8", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on the...

    $174.73
    Add to Cart
  • An image of a 16 Gallon Marine Holding Tank | B107

    7 Gallon Marine Fresh Water Tank | BOAT56W

    This 7-gallon Ronco marine fresh water tank (BOAT56W) is built for onboard potable water storage on boats and watercraft. Measuring 20 1/2" x 12 3/4" x 8", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended...

    $210.88
    Add to Cart
  • An image of a 108 Gallon PP Ronco White Rectangular Open Top Tank | 30X30X30PP

    7 Gallon Marine Fresh Water Tank | B535

    This 7-gallon Ronco marine fresh water tank (B535) is built for onboard potable water storage on boats and watercraft. Measuring 13" x 12" x 12", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on the...

    $139.59
    Add to Cart
  • An image of a 50 Gallon Marine Holding Tank | B178

    7 Gallon Marine Fresh Water Tank | B395

    This 7-gallon Ronco marine fresh water tank (B395) is built for onboard potable water storage on boats and watercraft. Measuring 27" x 14 3/8" x 5", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on...

    $175.74
    Add to Cart
  • An image of a 200 Gallon PP Ronco White Cylindrical Open Top Tank | 200PP

    7 Gallon Marine Fresh Water Tank | B344

    This 7-gallon Ronco marine fresh water tank (B344) is built for onboard potable water storage on boats and watercraft. Measuring 21 1/2" x 10" x 8 3/4", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips...

    $175.74
    Add to Cart
  • An image of a 71 Gallon PE Ronco White Rectangular Open Top Tank | 36X14X36PE

    7 Gallon Marine Fresh Water Tank | B326

    This 7-gallon Ronco marine fresh water tank (B326) is built for onboard potable water storage on boats and watercraft. Measuring 12" x 12" x 12", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on the...

    $139.59
    Add to Cart
  • An image of a 31 Gallon PE Ronco White Rectangular Open Top Tank | 24X18X18PE

    7 Gallon Marine Fresh Water Tank | B287

    This 7-gallon Ronco marine fresh water tank (B287) is built for onboard potable water storage on boats and watercraft. Measuring 27" x 10 1/4" x 6 1/2", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips...

    $174.73
    Add to Cart
  • An image of a 20 Gallon Marine Fresh Water Tank | B213

    7 Gallon Marine Fresh Water Tank | B275

    This 7-gallon Ronco marine fresh water tank (B275) is built for onboard potable water storage on boats and watercraft. Measuring 15 5/8" x 15 1/8" x 7 3/4", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended...

    $174.73
    Add to Cart
  • An image of a 80 Gallon PE Ronco White Cylindrical Open Top Tank | 80LDPE

    7 Gallon Marine Fresh Water Tank | B272

    This 7-gallon Ronco marine fresh water tank (B272) is built for onboard potable water storage on boats and watercraft. Measuring 24 1/4" x 12 1/2" x 5 3/4", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended...

    $174.73
    Add to Cart
  • An image of a 15 Gallon Marine Fresh Water Tank | B131

    7 Gallon Marine Fresh Water Tank | B271

    This 7-gallon Ronco marine fresh water tank (B271) is built for onboard potable water storage on boats and watercraft. Measuring 9 1/4" x 13 1/8" x 7 1/8", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended...

    $174.73
    Add to Cart
  • An image of a 18 Gallon Marine Holding Tank | B108

    8 Gallon Marine Fresh Water Tank | BOAT41W

    This 8-gallon Ronco marine fresh water tank (BOAT41W) is built for onboard potable water storage on boats and watercraft. Measuring 17" x 12 3/4" x 10", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips...

    $187.79
    Add to Cart
  • An image of a 30 Gallon Marine Holding Tank | B228

    8 Gallon Marine Fresh Water Tank | BOAT21W

    This 8-gallon Ronco marine fresh water tank (BOAT21W) is built for onboard potable water storage on boats and watercraft. Measuring 17 3/4" x 15 3/4" x 8 1/4", 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 24 Gallon PP Ronco White Rectangular Open Top Tank | 23X15X18PP

    8 Gallon Marine Fresh Water Tank | B360

    This 8-gallon Ronco marine fresh water tank (B360) is built for onboard potable water storage on boats and watercraft. Measuring 23 1/2" x 10" x 8 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 20 Gallon Marine Fresh Water Tank | B185

    8 Gallon Marine Fresh Water Tank | B280

    This 8-gallon Ronco marine fresh water tank (B280) is built for onboard potable water storage on boats and watercraft. Measuring 18" x 14 5/8" x 10", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on...

    $210.88
    Add to Cart
  • An image of a 6 Gallon PP Ronco White Cylindrical Open Top Tank | 6PP

    8 Gallon Marine Fresh Water Tank | B270

    This 8-gallon Ronco marine fresh water tank (B270) is built for onboard potable water storage on boats and watercraft. Measuring 24" x 12 1/4" x 6 7/8", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips...

    $197.83
    Add to Cart