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 | B449

    50 Gallon Marine Fresh Water Tank | B308

    This 50-gallon Ronco marine fresh water tank (B308) is built for onboard potable water storage on boats and watercraft. Measuring 64" x 22" x 9 1/8", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on...

    $491.07
    Add to Cart
  • An image of a 13 Gallon RV Holding Tank | RV26H

    50 Gallon Marine Fresh Water Tank | B210

    This 50-gallon Ronco marine fresh water tank (B210) is built for onboard potable water storage on boats and watercraft. Measuring 33" x 27" x 14", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on the...

    $466.97
    Add to Cart
  • An image of a 95 Gallon Marine Fresh Water Tank | B448

    50 Gallon Marine Fresh Water Tank | B198

    This 50-gallon Ronco marine fresh water tank (B198) is built for onboard potable water storage on boats and watercraft. Measuring 31 1/4" x 22" x 19", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on...

    $550.32
    Add to Cart
  • An image of a 20 Gallon RV Fresh Water Tank | RVB234

    50 Gallon Marine Fresh Water Tank | B178

    This 50-gallon Ronco marine fresh water tank (B178) is built for onboard potable water storage on boats and watercraft. Measuring 60 3/4" x 33 1/2" x 14 1/2", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended...

    $667.82
    Add to Cart
  • An image of a 38 Gallon RV Fresh Water Tank | RV53W

    50 Gallon Marine Fresh Water Tank | B177

    This 50-gallon Ronco marine fresh water tank (B177) is built for onboard potable water storage on boats and watercraft. Measuring 57" x 28 1/2" x 26", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on...

    $667.82
    Add to Cart
  • An image of a 28 Gallon Marine Fresh Water Tank | B394

    50 Gallon Marine Fresh Water Tank | B156

    This 50-gallon Ronco marine fresh water tank (B156) is built for onboard potable water storage on boats and watercraft. Measuring 40" x 20" x 16", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on the...

    $491.07
    Add to Cart
  • 50 Gallon Marine Water Tank MW-533. Technical drawing of a polyethylene water tank designed for marine vessels.

    50 Gallon Marine Water Tank MW-533

    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 50 Gallon Marine Water Tank, Part# MW-533, is engineered to meet the requirements of mobile...

    MSRP: $401.44
    $381.68
    Add to Cart
  • 50 Gallon Marine Water Tank MW-480. Technical drawing of a polyethylene water tank designed for marine vessels.

    50 Gallon Marine Water Tank MW-480

    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 50 Gallon Marine Water Tank, Part# MW-480, is engineered to meet the requirements of mobile...

    MSRP: $371.67
    $353.37
    Add to Cart
  • 50 Gallon Marine Water Tank MW-330. Technical drawing of a polyethylene water tank designed for marine vessels.

    50 Gallon Marine Water Tank MW-330

    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 50 Gallon Marine Water Tank, Part# MW-330, is engineered to meet the requirements of mobile...

    MSRP: $485.96
    $462.04
    Add to Cart
  • 50 Gallon Marine Water Tank MW-289. Technical drawing of a polyethylene water tank designed for marine vessels.

    50 Gallon Marine Water Tank MW-289

    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 50 Gallon Marine Water Tank, Part# MW-289, is engineered to meet the requirements of mobile...

    MSRP: $413.18
    $392.84
    Add to Cart
  • 50 Gallon Marine Water Tank MW-271. Technical drawing of a polyethylene water tank designed for marine vessels.

    50 Gallon Marine Water Tank MW-271

    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 50 Gallon Marine Water Tank, Part# MW-271, is engineered to meet the requirements of mobile...

    MSRP: $492.94
    $468.67
    Add to Cart
  • 50 Gallon Marine Water Tank MW-249. Technical drawing of a polyethylene water tank designed for marine vessels.

    50 Gallon Marine Water Tank MW-249

    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 50 Gallon Marine Water Tank, Part# MW-249, is engineered to meet the requirements of mobile...

    MSRP: $325.21
    $309.20
    Add to Cart
  • 50 Gallon Marine Water Tank MW-24. Technical drawing of a polyethylene water tank designed for marine vessels.

    50 Gallon Marine Water Tank MW-24

    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 50 Gallon Marine Water Tank, Part# MW-24, is engineered to meet the requirements of mobile...

    MSRP: $376.45
    $357.93
    Add to Cart
  • 50 Gallon Marine Water Tank MW-208. Technical drawing of a polyethylene water tank designed for marine vessels.

    50 Gallon Marine Water Tank MW-208

    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 50 Gallon Marine Water Tank, Part# MW-208, is engineered to meet the requirements of mobile...

    MSRP: $573.18
    $544.96
    Add to Cart
  • 51 Gallon Marine Water Tank MW-532. Technical drawing of a polyethylene water tank designed for marine vessels.

    51 Gallon Marine Water Tank MW-532

    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 51 Gallon Marine Water Tank, Part# MW-532, is engineered to meet the requirements of mobile...

    MSRP: $783.22
    $744.66
    Add to Cart
  • An image of a 42 Gallon Marine Holding Tank | B510

    52 Gallon Marine Fresh Water Tank | BOAT48W

    This 52-gallon Ronco marine fresh water tank (BOAT48W) is built for onboard potable water storage on boats and watercraft. Measuring 40" x 24" x 14", 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 12 Gallon RV Fresh Water Tank | RVB105

    52 Gallon Marine Fresh Water Tank | B422

    This 52-gallon Ronco marine fresh water tank (B422) is built for onboard potable water storage on boats and watercraft. Measuring 65 1/2" x 32" x 12 1/4", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended...

    $632.67
    Add to Cart
  • An image of a 7 Gallon Marine Fresh Water Tank | B344

    52 Gallon Marine Fresh Water Tank | B333

    This 52-gallon Ronco marine fresh water tank (B333) is built for onboard potable water storage on boats and watercraft. Measuring 56 1/2" x 18 1/2" x 14", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended...

    $538.27
    Add to Cart
  • An image of a 11 Gallon Marine Holding Tank | BOAT16W

    52 Gallon Marine Fresh Water Tank | B315

    This 52-gallon Ronco marine fresh water tank (B315) is built for onboard potable water storage on boats and watercraft. Measuring 30 1/2" x 24 3/8" x 17 3/8", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended...

    $491.07
    Add to Cart
  • An image of a 19 Gallon Marine Fresh Water Tank | B480

    52 Gallon Marine Fresh Water Tank | B295

    This 52-gallon Ronco marine fresh water tank (B295) is built for onboard potable water storage on boats and watercraft. Measuring 28" x 23" x 21", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on the...

    $491.07
    Add to Cart
  • 52 Gallon Marine Water Tank MW-212. Technical drawing of a polyethylene water tank designed for marine vessels.

    52 Gallon Marine Water Tank MW-212

    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 52 Gallon Marine Water Tank, Part# MW-212, is engineered to meet the requirements of mobile...

    MSRP: $490.53
    $466.37
    Add to Cart
  • An image of a 23 Gallon Marine Fresh Water Tank | B450

    53 Gallon Marine Fresh Water Tank | B545

    This 53-gallon Ronco marine fresh water tank (B545) is built for onboard potable water storage on boats and watercraft. Measuring 30" x 22" x 20 1/2", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on...

    $502.11
    Add to Cart
  • An image of a 18 Gallon Marine Holding Tank | B211

    53 Gallon Marine Fresh Water Tank | B312

    This 53-gallon Ronco marine fresh water tank (B312) is built for onboard potable water storage on boats and watercraft. Measuring 72" x 15" x 13", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips on the...

    $491.07
    Add to Cart
  • An image of a 15 Gallon RV Fresh Water Tank | RV11W

    53 Gallon Marine Fresh Water Tank | B133

    This 53-gallon Ronco marine fresh water tank (B133) is built for onboard potable water storage on boats and watercraft. Measuring 57" x 26 1/2" x 9 1/4", it fits a wide range of vessel layouts and provides reliable fresh water capacity for extended trips...

    $491.07
    Add to Cart
  • 53 Gallon Marine Water Tank MW-456. Technical drawing of a polyethylene water tank designed for marine vessels.

    53 Gallon Marine Water Tank MW-456

    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 53 Gallon Marine Water Tank, Part# MW-456, is engineered to meet the requirements of mobile...

    MSRP: $507.27
    $482.30
    Add to Cart