Marine and RV Water and Holding Tanks for Sale

Pick the size, the shape, and the fitting locations to make a perfect fit for your Marine or RV Water and Holding Tank replacement.   You won’t find better-made RV or Marine holding 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. The bottom line: These tanks are nearly unbreakable and are built to go the distance, at sea or on the road.

Fittings: You 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 RV freshwater tanks, RV holding tanks, RV black water holding tanks, RV waste holding tanks, Marine fresh water tanks, Marine holding tanks, and more!

We have 100's of sizes ranging from 2 gallons, 40 gallons, 50 gallons, 100 gallons, up to 250 gallons for these marine and rv fresh water and holding tanks.

  • Marine Holding Tanks
  • Marine Water Tanks
  • RV holding Tanks
  • RV Water Tanks
  • RV Black Water Tanks

Shop by Category

RV & Marine Tanks

  • 35 Gallon RV Water Tank W-363. Technical drawing of a polyethylene water tank designed for your rv.

    35 Gallon RV Water Tank W-363

    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 35 Gallon RV Water Tank, Part# W-363, is engineered to meet the requirements of mobile water...

    MSRP: $233.27
    $221.79
    Add to Cart
  • 35 Gallon RV Water Tank W-322. Technical drawing of a polyethylene water tank designed for your rv.

    35 Gallon RV Water Tank W-322

    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 35 Gallon RV Water Tank, Part# W-322, is engineered to meet the requirements of mobile water...

    MSRP: $220.31
    $209.47
    Add to Cart
  • 35 Gallon Marine Water Tank MW-412. Technical drawing of a polyethylene water tank designed for marine vessels.

    35 Gallon Marine Water Tank MW-412

    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 35 Gallon Marine Water Tank, Part# MW-412, is engineered to meet the requirements of mobile...

    MSRP: $378.50
    $359.86
    Add to Cart
  • 35 Gallon Marine Water Tank MW-363. Technical drawing of a polyethylene water tank designed for marine vessels.

    35 Gallon Marine Water Tank MW-363

    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 35 Gallon Marine Water Tank, Part# MW-363, is engineered to meet the requirements of mobile...

    MSRP: $479.51
    $455.91
    Add to Cart
  • 35 Gallon Marine Water Tank MW-322. Technical drawing of a polyethylene water tank designed for marine vessels.

    35 Gallon Marine Water Tank MW-322

    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 35 Gallon Marine Water Tank, Part# MW-322, is engineered to meet the requirements of mobile...

    MSRP: $309.25
    $294.02
    Add to Cart
  • 35 Gallon RV Holding Tank H-650. Technical drawing of a polyethylene holding tank designed for your rv and camper.

    35 Gallon RV Holding Tank H-650

    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 35 Gallon RV Holding Tank, Part# H-650, is engineered to meet the requirements of mobile...

    MSRP: $336.95
    $320.36
    Add to Cart
  • 35 Gallon RV Holding Tank H-625. Technical drawing of a polyethylene holding tank designed for your rv and camper.

    35 Gallon RV Holding Tank H-625

    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 35 Gallon RV Holding Tank, Part# H-625, is engineered to meet the requirements of mobile...

    MSRP: $259.19
    $246.44
    Add to Cart
  • 35 Gallon RV Holding Tank H-624. Technical drawing of a polyethylene holding tank designed for your rv and camper.

    35 Gallon RV Holding Tank H-624

    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 35 Gallon RV Holding Tank, Part# H-624, is engineered to meet the requirements of mobile...

    MSRP: $259.19
    $246.44
    Add to Cart
  • 35 Gallon RV Holding Tank H-605. Technical drawing of a polyethylene holding tank designed for your rv and camper.

    35 Gallon RV Holding Tank H-605

    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 35 Gallon RV Holding Tank, Part# H-605, is engineered to meet the requirements of mobile...

    MSRP: $207.36
    $197.15
    Add to Cart
  • 35 Gallon RV Holding Tank H-527 . Technical drawing of a polyethylene holding tank designed for your rv and camper.

    35 Gallon RV Holding Tank H-527

    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 35 Gallon RV Holding Tank, Part# H-527, is engineered to meet the requirements of mobile...

    MSRP: $240.00
    $228.19
    Add to Cart
  • 35 Gallon RV Holding Tank H-450L. Technical drawing of a polyethylene holding tank designed for your rv and camper.

    35 Gallon RV Holding Tank H-450L

    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 35 Gallon RV Holding Tank, Part# H-450L, is engineered to meet the requirements of mobile...

    MSRP: $311.03
    $295.72
    Add to Cart
  • 35 Gallon RV Holding Tank H-420 . Technical drawing of a polyethylene holding tank designed for your rv and camper.

    35 Gallon RV Holding Tank H-420

    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 35 Gallon RV Holding Tank, Part# H-420, is engineered to meet the requirements of mobile...

    MSRP: $298.07
    $283.39
    Add to Cart
  • 35 Gallon RV Holding Tank H-416 . Technical drawing of a polyethylene holding tank designed for your rv and camper.

    35 Gallon RV Holding Tank H-416

    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 35 Gallon RV Holding Tank, Part# H-416, is engineered to meet the requirements of mobile...

    MSRP: $298.07
    $283.39
    Add to Cart
  • 35 Gallon RV Holding Tank H-396 . Technical drawing of a polyethylene holding tank designed for your rv and camper.

    35 Gallon RV Holding Tank H-396

    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 35 Gallon RV Holding Tank, Part# H-396, is engineered to meet the requirements of mobile...

    MSRP: $311.03
    $295.72
    Add to Cart
  • 35 Gallon RV Holding Tank H-318 [OR] . Technical drawing of a polyethylene holding tank designed for your rv and camper.

    35 Gallon RV Holding Tank H-318 [OR]

    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 35 Gallon RV Holding Tank, Part# H-318 [OR], is engineered to meet the requirements of mobile...

    MSRP: $298.07
    $283.39
    Add to Cart
  • 35 Gallon RV Holding Tank H-305 . Technical drawing of a polyethylene holding tank designed for your rv and camper.

    35 Gallon RV Holding Tank H-305

    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 35 Gallon RV Holding Tank, Part# H-305, is engineered to meet the requirements of mobile...

    MSRP: $259.19
    $246.44
    Add to Cart
  • 35 Gallon RV Holding Tank H-286 . Technical drawing of a polyethylene holding tank designed for your rv and camper.

    35 Gallon RV Holding Tank H-286

    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 35 Gallon RV Holding Tank, Part# H-286, is engineered to meet the requirements of mobile...

    MSRP: $259.19
    $246.44
    Add to Cart
  • 35 Gallon RV Holding Tank H-251 . Technical drawing of a polyethylene holding tank designed for your rv and camper.

    35 Gallon RV Holding Tank H-251

    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 35 Gallon RV Holding Tank, Part# H-251, is engineered to meet the requirements of mobile...

    MSRP: $220.31
    $209.47
    Add to Cart
  • 35 Gallon RV Holding Tank H-233 . Technical drawing of a polyethylene holding tank designed for your rv and camper.

    35 Gallon RV Holding Tank H-233

    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 35 Gallon RV Holding Tank, Part# H-233, is engineered to meet the requirements of mobile...

    MSRP: $314.87
    $299.37
    Add to Cart
  • 35 Gallon RV Holding Tank H-208. Technical drawing of a polyethylene holding tank designed for your rv and camper.

    35 Gallon RV Holding Tank H-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 35 Gallon RV Holding Tank, Part# H-208, is engineered to meet the requirements of mobile...

    MSRP: $285.11
    $271.08
    Add to Cart
  • 35 Gallon RV Holding Tank H-37. Technical drawing of a polyethylene holding tank designed for your rv and camper.

    35 Gallon RV Holding Tank H-37

    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 35 Gallon RV Holding Tank, Part# H-37, is engineered to meet the requirements of mobile...

    MSRP: $336.95
    $320.36
    Add to Cart
  • An image of a 22 Gallon RV Fresh Water Tank | RVB276

    36 Gallon RV Fresh Water Tank | RVB428

    Upgrade your RV with the 36 Gallon RV Fresh Water Tank from One Clarion. This rectangular tank is designed for portable use and is suitable for above ground environments. Made from polyethylene in a natural white color, this tank measures 46" in length,...

    $400.69
    Add to Cart
  • An image of a 7 Gallon RV Holding Tank | RV9H

    36 Gallon RV Fresh Water Tank | RVB383

    Upgrade your RV with the 36 Gallon RV Fresh Water Tank from One Clarion. This rectangular tank is designed for portable use and is suitable for above ground environments. With dimensions of 32" in length, 32" in width, and 9 1/4" in height, this tank is...

    $341.43
    Add to Cart
  • An image of a 40 Gallon Marine Holding Tank | B301

    36 Gallon RV Fresh Water Tank | RVB254

    The 36 Gallon RV Fresh Water Tank by One Clarion is a must-have for any RV owner. This portable tank is designed specifically for RVs and is shaped in a convenient rectangular shape. It is suitable for use above ground and is made from durable...

    $295.24
    Add to Cart
  • An image of a 36 Gallon Marine Fresh Water Tank | B428

    36 Gallon RV Fresh Water Tank | RVB158

    The 36 Gallon RV Fresh Water Tank by One Clarion is a must-have for any RV owner. This portable tank is designed specifically for RVs and is shaped in a convenient rectangular shape. It is made from high-quality polyethylene material, ensuring durability...

    $295.24
    Add to Cart
  • An image of a 7 Gallon RV Fresh Water Tank | RVB272

    36 Gallon RV Holding Tank | RV85H

    Introducing the 36 Gallon RV Holding Tank by One Clarion. This rectangular tank is designed specifically for RV use, making it the perfect portable solution for your waste management needs. With its above ground placement, you can easily access and...

    $456.93
    Add to Cart
  • An image of a 110 Gallon Marine Holding Tank | B433

    36 Gallon RV Fresh Water Tank | RV7W

    The 36 Gallon RV Fresh Water Tank is a rectangular-shaped portable water tank designed for above ground use. This tank is made of polyethylene material and comes in a natural white color. It measures 30 inches in length, 22 inches in width, and 14 inches...

    $375.58
    Add to Cart
  • An image of a 15 Gallon Marine Fresh Water Tank | B175

    36 Gallon RV Fresh Water Tank | RV6W

    Upgrade your RV with the 36 Gallon RV Fresh Water Tank from One Clarion. This rectangular tank is designed for portable use and is suitable for above ground environments. Made from polyethylene in a natural white color, this tank is 48 3/8" in length, 14...

    $375.58
    Add to Cart
  • An image of a 13 Gallon Marine Holding Tank | BOAT37W

    36 Gallon RV Holding Tank | RV48H

    Upgrade your RV with the 36 Gallon RV Holding Tank from One Clarion. This rectangular tank is designed for portable use and is suitable for above ground environments. Made from polyethylene and measuring 35" in length, 25" in width, and 13" in height,...

    $316.33
    Add to Cart
  • An image of a 22 Gallon Marine Fresh Water Tank | B337

    36 Gallon RV Fresh Water Tank | RV38W

    Introducing the 36 Gallon RV Fresh Water Tank by One Clarion. This rectangular tank is designed specifically for RV use, making it portable and easy to transport. With its above ground environment, you can conveniently access and refill your water supply...

    $375.58
    Add to Cart
  • An image of a 36 Gallon RV Fresh Water Tank | RV38W

    36 Gallon RV Holding Tank | RV37H

    Introducing the 36 Gallon RV Holding Tank by One Clarion. This rectangular tank is designed specifically for RV use, making it the perfect portable solution for your waste management needs. With its above ground placement, you can easily access and...

    $386.63
    Add to Cart
  • An image of a 42 Gallon Marine Holding Tank | B443

    36 Gallon Marine Fresh Water Tank | B478

    Introducing the 36 Gallon Marine Fresh Water Tank by One Clarion. This portable tank is perfect for marine environments and is designed to be used above ground. With its rectangular shape, it offers a spacious capacity of 36 gallons, providing ample...

    $362.53
    Add to Cart