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

  • 81 Gallon Marine Water Tank MW-281. Technical drawing of a polyethylene water tank designed for marine vessels.

    81 Gallon Marine Water Tank MW-281

    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 81 Gallon Marine Water Tank, Part# MW-281, is engineered to meet the requirements of mobile...

    MSRP: $652.30
    $620.19
    Add to Cart
  • An image of a 18 Gallon Marine Fresh Water Tank | B192

    82 Gallon Marine Fresh Water Tank | B454

    This 82-gallon Ronco marine fresh water tank (B454) is built for onboard potable water storage on boats and watercraft. Measuring 55" x 14 3/4" x 30 1/8", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended...

    $819.46
    Add to Cart
  • 83 Gallon Marine Water Tank MW-553. Technical drawing of a polyethylene water tank designed for marine vessels.

    83 Gallon Marine Water Tank MW-553

    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 83 Gallon Marine Water Tank, Part# MW-553, is engineered to meet the requirements of mobile...

    MSRP: $704.22
    $669.55
    Add to Cart
  • 85 Gallon Marine Water Tank MW-550. Technical drawing of a polyethylene water tank designed for marine vessels.

    85 Gallon Marine Water Tank MW-550

    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 85 Gallon Marine Water Tank, Part# MW-550, is engineered to meet the requirements of mobile...

    MSRP: $1,186.92
    $1,128.49
    Add to Cart
  • 85 Gallon Marine Water Tank MW-549. Technical drawing of a polyethylene water tank designed for marine vessels.

    85 Gallon Marine Water Tank MW-549

    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 85 Gallon Marine Water Tank, Part# MW-549, is engineered to meet the requirements of mobile...

    MSRP: $918.71
    $873.48
    Add to Cart
  • 85 Gallon Marine Water Tank MW-487. Technical drawing of a polyethylene water tank designed for marine vessels.

    85 Gallon Marine Water Tank MW-487

    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 85 Gallon Marine Water Tank, Part# MW-487, is engineered to meet the requirements of mobile...

    MSRP: $912.46
    $867.55
    Add to Cart
  • An image of a 5 Gallon RV Fresh Water Tank | RVB322

    86 Gallon Marine Fresh Water Tank | BOAT64W

    This 86-gallon Ronco marine fresh water tank (BOAT64W) is built for onboard potable water storage on boats and watercraft. Measuring 39 1/4" x 39 1/4" x 14 1/2", it fits a wide range of vessel layouts and provides reliable fresh water capacity for...

    $608.57
    Add to Cart
  • An image of a 15 Gallon RV Fresh Water Tank | RVB131

    90 Gallon Marine Fresh Water Tank | B314

    This 90-gallon Ronco marine fresh water tank (B314) is built for onboard potable water storage on boats and watercraft. Measuring 34" x 32" x 21", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on the...

    $666.81
    Add to Cart
  • An image of a 17 Gallon RV Holding Tank | RV2H

    90 Gallon Marine Fresh Water Tank | B204

    This 90-gallon Ronco marine fresh water tank (B204) is built for onboard potable water storage on boats and watercraft. Measuring 76" x 27" x 11 1/2", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on...

    $689.91
    Add to Cart
  • 90 Gallon Marine Water Tank MW-552. Technical drawing of a polyethylene water tank designed for marine vessels.

    90 Gallon Marine Water Tank MW-552

    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 90 Gallon Marine Water Tank, Part# MW-552, is engineered to meet the requirements of mobile...

    MSRP: $953.61
    $906.66
    Add to Cart
  • 90 Gallon Marine Water Tank MW-539. Technical drawing of a polyethylene water tank designed for marine vessels.

    90 Gallon Marine Water Tank MW-539

    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 90 Gallon Marine Water Tank, Part# MW-539, is engineered to meet the requirements of mobile...

    MSRP: $734.76
    $698.59
    Add to Cart
  • An image of a 40 Gallon RV Holding Tank | RV84H

    92 Gallon Marine Fresh Water Tank | B483

    This 92-gallon Ronco marine fresh water tank (B483) is built for onboard potable water storage on boats and watercraft. Measuring 53" x 31" x 14 1/4", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on...

    $666.81
    Add to Cart
  • An image of a 50 Gallon RV Fresh Water Tank | RVB210

    92 Gallon Marine Fresh Water Tank | B387

    This 92-gallon Ronco marine fresh water tank (B387) is built for onboard potable water storage on boats and watercraft. Measuring 72" x 33" x 10", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on the...

    $666.81
    Add to Cart
  • An image of a 80 Gallon Marine Holding Tank | B458

    93 Gallon Marine Fresh Water Tank | BOAT66W

    This 93-gallon Ronco marine fresh water tank (BOAT66W) is built for onboard potable water storage on boats and watercraft. Measuring 67" x 22" x 16", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on...

    $632.67
    Add to Cart
  • 93 Gallon Marine Water Tank MW-353. Technical drawing of a polyethylene water tank designed for marine vessels.

    93 Gallon Marine Water Tank MW-353

    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 93 Gallon Marine Water Tank, Part# MW-353, is engineered to meet the requirements of mobile...

    MSRP: $669.91
    $636.93
    Add to Cart
  • An image of a 130 Gallon Marine Fresh Water Tank | B356

    95 Gallon Marine Fresh Water Tank | B448

    This 95-gallon Ronco marine fresh water tank (B448) is built for onboard potable water storage on boats and watercraft. Measuring 90" x 19" x 15", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on the...

    $819.46
    Add to Cart
  • An image of a 43 Gallon RV Fresh Water Tank | RVB220

    95 Gallon Marine Fresh Water Tank | B354

    This 95-gallon Ronco marine fresh water tank (B354) is built for onboard potable water storage on boats and watercraft. Measuring 47" x 33" x 16", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on the...

    $689.91
    Add to Cart
  • An image of a 50 Gallon Ronco White Vertical Storage Tank | RPV50

    95 Gallon Marine Fresh Water Tank | B259

    This 95-gallon Ronco marine fresh water tank (B259) is built for onboard potable water storage on boats and watercraft. Measuring 71 1/2" x 26" x 13", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on...

    $689.91
    Add to Cart
  • 95 Gallon Marine Water Tank MW-544. Technical drawing of a polyethylene water tank designed for marine vessels.

    95 Gallon Marine Water Tank MW-544

    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 95 Gallon Marine Water Tank, Part# MW-544, is engineered to meet the requirements of mobile...

    MSRP: $766.03
    $728.31
    Add to Cart
  • 95 Gallon Marine Water Tank MW-326. Technical drawing of a polyethylene water tank designed for marine vessels.

    95 Gallon Marine Water Tank MW-326

    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 95 Gallon Marine Water Tank, Part# MW-326, is engineered to meet the requirements of mobile...

    MSRP: $719.87
    $684.42
    Add to Cart
  • 95 Gallon Marine Water Tank MW-246. Technical drawing of a polyethylene water tank designed for marine vessels.

    95 Gallon Marine Water Tank MW-246

    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 95 Gallon Marine Water Tank, Part# MW-246, is engineered to meet the requirements of mobile...

    MSRP: $722.15
    $686.60
    Add to Cart
  • 95 Gallon Marine Water Tank MW-230. Technical drawing of a polyethylene water tank designed for marine vessels.

    95 Gallon Marine Water Tank MW-230

    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 95 Gallon Marine Water Tank, Part# MW-230, is engineered to meet the requirements of mobile...

    MSRP: $819.96
    $779.60
    Add to Cart
  • 95 Gallon Marine Water Tank MW-218. Technical drawing of a polyethylene water tank designed for marine vessels.

    95 Gallon Marine Water Tank MW-218

    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 95 Gallon Marine Water Tank, Part# MW-218, is engineered to meet the requirements of mobile...

    MSRP: $501.60
    $476.90
    Add to Cart
  • An image of a 7 Gallon RV Fresh Water Tank | RVB326

    97 Gallon Marine Fresh Water Tank | B487

    This 97-gallon Ronco marine fresh water tank (B487) is built for onboard potable water storage on boats and watercraft. Measuring 63" x 40" x 10", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on the...

    $689.91
    Add to Cart
  • 97 Gallon Marine Water Tank MW-303. Technical drawing of a polyethylene water tank designed for marine vessels.

    97 Gallon Marine Water Tank MW-303

    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 97 Gallon Marine Water Tank, Part# MW-303, is engineered to meet the requirements of mobile...

    MSRP: $682.40
    $648.81
    Add to Cart
  • An image of a 60 Gallon Marine Holding Tank | BOAT54W

    98 Gallon Marine Fresh Water Tank | B530

    This 98-gallon Ronco marine fresh water tank (B530) is built for onboard potable water storage on boats and watercraft. Measuring 44" x 25" x 23", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on the...

    $935.95
    Add to Cart
  • An image of a 25 Gallon RV Holding Tank | RV31H

    98 Gallon Marine Fresh Water Tank | B477

    This 98-gallon Ronco marine fresh water tank (B477) is built for onboard potable water storage on boats and watercraft. Measuring 35" x 27" x 26", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on the...

    $783.30
    Add to Cart
  • 98 Gallon Marine Water Tank MW-214. Technical drawing of a polyethylene water tank designed for marine vessels.

    98 Gallon Marine Water Tank MW-214

    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 98 Gallon Marine Water Tank, Part# MW-214, is engineered to meet the requirements of mobile...

    MSRP: $556.72
    $529.32
    Add to Cart
  • 99 Gallon Marine Water Tank MW-554. Technical drawing of a polyethylene water tank designed for marine vessels.

    99 Gallon Marine Water Tank MW-554

    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 99 Gallon Marine Water Tank, Part# MW-554, is engineered to meet the requirements of mobile...

    MSRP: $725.31
    $689.61
    Add to Cart
  • An image of a 7 Gallon Marine Fresh Water Tank | B535

    100 Gallon Marine Fresh Water Tank | B455

    This 100-gallon Ronco marine fresh water tank (B455) is built for onboard potable water storage on boats and watercraft. Measuring 44" x 24" x 24", 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 36 Gallon RV Fresh Water Tank | RVB254

    100 Gallon Marine Fresh Water Tank | B426

    This 100-gallon Ronco marine fresh water tank (B426) is built for onboard potable water storage on boats and watercraft. Measuring 48" x 34" x 15", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on...

    $912.86
    Add to Cart