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 32 Gallon Marine Holding Tank | B141

    26 Gallon Marine Fresh Water Tank | B338

    This 26-gallon Ronco marine fresh water tank (B338) is built for onboard potable water storage on boats and watercraft. Measuring 30 1/4" x 13 1/4" x 28", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended...

    $362.53
    Add to Cart
  • An image of a 80 Gallon Marine Fresh Water Tank | B260

    26 Gallon Marine Fresh Water Tank | B332

    This 26-gallon Ronco marine fresh water tank (B332) is built for onboard potable water storage on boats and watercraft. Measuring 20" x 16 1/2" x 23 1/2", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended...

    $362.53
    Add to Cart
  • An image of a 24 Gallon Marine Fresh Water Tank | B114

    26 Gallon Marine Fresh Water Tank | B329

    This 26-gallon Ronco marine fresh water tank (B329) is built for onboard potable water storage on boats and watercraft. Measuring 76" x 12 3/4" x 10 1/2", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended...

    $386.63
    Add to Cart
  • An image of a 18 Gallon Marine Fresh Water Tank | B352

    26 Gallon Marine Fresh Water Tank | B145

    This 26-gallon Ronco marine fresh water tank (B145) is built for onboard potable water storage on boats and watercraft. Measuring 42" x 19" x 11 1/2", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on...

    $362.53
    Add to Cart
  • 26 Gallon Marine Water Tank MW-466. Technical drawing of a polyethylene water tank designed for marine vessels.

    26 Gallon Marine Water Tank MW-466

    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 26 Gallon Marine Water Tank, Part# MW-466, is engineered to meet the requirements of mobile...

    MSRP: $256.37
    $243.75
    Add to Cart
  • 26 Gallon Marine Water Tank MW-440. Technical drawing of a polyethylene water tank designed for marine vessels.

    26 Gallon Marine Water Tank MW-440

    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 26 Gallon Marine Water Tank, Part# MW-440, is engineered to meet the requirements of mobile...

    MSRP: $334.55
    $318.07
    Add to Cart
  • 26 Gallon Marine Water Tank MW-201. Technical drawing of a polyethylene water tank designed for marine vessels.

    26 Gallon Marine Water Tank MW-201

    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 26 Gallon Marine Water Tank, Part# MW-201, is engineered to meet the requirements of mobile...

    MSRP: $363.76
    $345.85
    Add to Cart
  • An image of a 125 Gallon Marine Fresh Water Tank | B243

    27 Gallon Marine Fresh Water Tank | BOAT24W

    This 27-gallon Ronco marine fresh water tank (BOAT24W) is built for onboard potable water storage on boats and watercraft. Measuring 43" x 16" x 10 1/2", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips...

    $327.38
    Add to Cart
  • An image of a 10 Gallon RV Fresh Water Tank | RVB263

    27 Gallon Marine Fresh Water Tank | B459

    This 27-gallon Ronco marine fresh water tank (B459) is built for onboard potable water storage on boats and watercraft. Measuring 27" x 34 7/8" x 10", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on...

    $456.93
    Add to Cart
  • An image of a 58 Gallon Marine Holding Tank | BOAT63W

    27 Gallon Marine Fresh Water Tank | B420

    This 27-gallon Ronco marine fresh water tank (B420) is built for onboard potable water storage on boats and watercraft. Measuring 37" x 25 1/2" x 11", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on...

    $480.02
    Add to Cart
  • An image of a 27 Gallon Marine Fresh Water Tank | B459

    27 Gallon Marine Fresh Water Tank | B342

    This 27-gallon Ronco marine fresh water tank (B342) is built for onboard potable water storage on boats and watercraft. Measuring 42 1/4" x 22 1/4" x 11 1/2", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended...

    $386.63
    Add to Cart
  • 27 Gallon Marine Water Tank MW-85. Technical drawing of a polyethylene water tank designed for marine vessels.

    27 Gallon Marine Water Tank MW-85

    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 27 Gallon Marine Water Tank, Part# MW-85, is engineered to meet the requirements of mobile...

    MSRP: $291.63
    $277.28
    Add to Cart
  • 27 Gallon Marine Water Tank MW-534. Technical drawing of a polyethylene water tank designed for marine vessels.

    27 Gallon Marine Water Tank MW-534

    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 27 Gallon Marine Water Tank, Part# MW-534, is engineered to meet the requirements of mobile...

    MSRP: $595.53
    $566.21
    Add to Cart
  • 27 Gallon Marine Water Tank MW-473. Technical drawing of a polyethylene water tank designed for marine vessels.

    27 Gallon Marine Water Tank MW-473

    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 27 Gallon Marine Water Tank, Part# MW-473, is engineered to meet the requirements of mobile...

    MSRP: $442.41
    $420.63
    Add to Cart
  • 27 Gallon Marine Water Tank MW-335. Technical drawing of a polyethylene water tank designed for marine vessels.

    27 Gallon Marine Water Tank MW-335

    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 27 Gallon Marine Water Tank, Part# MW-335, is engineered to meet the requirements of mobile...

    MSRP: $333.41
    $316.99
    Add to Cart
  • 27 Gallon Marine Water Tank MW-31. Technical drawing of a polyethylene water tank designed for marine vessels.

    27 Gallon Marine Water Tank MW-31

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

    MSRP: $246.84
    $234.69
    Add to Cart
  • 27 Gallon Marine Water Tank MW-285. Technical drawing of a polyethylene water tank designed for marine vessels.

    27 Gallon Marine Water Tank MW-285

    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 27 Gallon Marine Water Tank, Part# MW-285, is engineered to meet the requirements of mobile...

    MSRP: $339.10
    $322.40
    Add to Cart
  • 27 Gallon Marine Water Tank MW-49. Technical drawing of a polyethylene water tank designed for marine vessels.

    27 Gallon Marine Water Tank MW-49

    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 27 Gallon Marine Water Tank, Part# MW-49, is engineered to meet the requirements of mobile...

    MSRP: $98.42
    $93.58
    Add to Cart
  • An image of a 60 Gallon Marine Holding Tank | B382

    28 Gallon Marine Fresh Water Tank | BOAT69W

    This 28-gallon Ronco marine fresh water tank (BOAT69W) is built for onboard potable water storage on boats and watercraft. Measuring 48" x 20" x 8", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on...

    $339.43
    Add to Cart
  • An image of a 62 Gallon Marine Fresh Water Tank | B244

    28 Gallon Marine Fresh Water Tank | BOAT52W

    This 28-gallon Ronco marine fresh water tank (BOAT52W) is built for onboard potable water storage on boats and watercraft. Measuring 60" x 16" x 8", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on...

    $339.43
    Add to Cart
  • An image of a 11 Gallon Marine Fresh Water Tank | B319

    28 Gallon Marine Fresh Water Tank | B437

    This 28-gallon Ronco marine fresh water tank (B437) is built for onboard potable water storage on boats and watercraft. Measuring 36" x 18" x 12", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on the...

    $326.38
    Add to Cart
  • An image of a 42 Gallon RV Fresh Water Tank | RVB443

    28 Gallon Marine Fresh Water Tank | B415

    This 28-gallon Ronco marine fresh water tank (B415) is built for onboard potable water storage on boats and watercraft. Measuring 39 3/4" x 19 3/4" x 15 1/2", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended...

    $456.93
    Add to Cart
  • An image of a 23 Gallon Marine Holding Tank | B499

    28 Gallon Marine Fresh Water Tank | B413

    This 28-gallon Ronco marine fresh water tank (B413) is built for onboard potable water storage on boats and watercraft. Measuring 36" x 24" x 14", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on the...

    $456.93
    Add to Cart
  • An image of a 36 Gallon Marine Holding Tank | B340

    28 Gallon Marine Fresh Water Tank | B394

    This 28-gallon Ronco marine fresh water tank (B394) is built for onboard potable water storage on boats and watercraft. Measuring 48" x 18 1/2" x 10", 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 23 Gallon Marine Fresh Water Tank | B498

    28 Gallon Marine Fresh Water Tank | B374

    This 28-gallon Ronco marine fresh water tank (B374) is built for onboard potable water storage on boats and watercraft. Measuring 27" x 24" x 19", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on the...

    $397.67
    Add to Cart
  • An image of a 254 Gallon PE Ronco White Rectangular Open Top Tank | 48X36X36PE

    28 Gallon Marine Fresh Water Tank | B335

    This 28-gallon Ronco marine fresh water tank (B335) is built for onboard potable water storage on boats and watercraft. Measuring 52" x 12" x 11", 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 9 Gallon Marine Holding Tank | B358

    28 Gallon Marine Fresh Water Tank | B273

    This 28-gallon Ronco marine fresh water tank (B273) is built for onboard potable water storage on boats and watercraft. Measuring 20 3/4" x 19 1/4" x 17 5/8", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended...

    $350.48
    Add to Cart
  • An image of a 28 Gallon Marine Fresh Water Tank | B169

    28 Gallon Marine Fresh Water Tank | B239

    This 28-gallon Ronco marine fresh water tank (B239) is built for onboard potable water storage on boats and watercraft. Measuring 48" x 14" x 10", 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 260 Gallon PP Ronco White Cylindrical Open Top Tank | 260PP

    28 Gallon Marine Fresh Water Tank | B206

    This 28-gallon Ronco marine fresh water tank (B206) is built for onboard potable water storage on boats and watercraft. Measuring 35 1/4" x 11" x 23 1/4", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended...

    $397.67
    Add to Cart
  • An image of a 27 Gallon Marine Fresh Water Tank | B420

    28 Gallon Marine Fresh Water Tank | B170

    This 28-gallon Ronco marine fresh water tank (B170) is built for onboard potable water storage on boats and watercraft. Measuring 35" x 21" x 14", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on the...

    $386.63
    Add to Cart
  • 28 Gallon Marine Fresh Water Tank | B169

    This 28-gallon Ronco marine fresh water tank (B169) is built for onboard potable water storage on boats and watercraft. Measuring 35" x 21" x 14", 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 28 Gallon Marine Holding Tank | B206

    28 Gallon Marine Fresh Water Tank | B161

    This 28-gallon Ronco marine fresh water tank (B161) is built for onboard potable water storage on boats and watercraft. Measuring 35 1/2" x 15" x 13", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on...

    $326.38
    Add to Cart