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

  • 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
  • An image of a 9 Gallon Marine Fresh Water Tank | B442

    36 Gallon Marine Holding Tank | B478

    Introducing the 36 Gallon Marine Holding Tank by One Clarion. This portable tank is designed specifically for marine use, making it the perfect solution for boat owners. With its rectangular shape and above ground usability, this tank is easy to...

    $362.53
    Add to Cart
  • An image of a 7 Gallon RV Fresh Water Tank | RVB275

    36 Gallon Marine Fresh Water Tank | B428

    Introducing the 36 Gallon Marine Fresh Water Tank by One Clarion. This portable tank is specifically designed for marine use, making it perfect for boating and other water activities. With its rectangular shape and above ground usability, it offers...

    $373.57
    Add to Cart
  • An image of a 14 Gallon RV Fresh Water Tank | RVB274

    36 Gallon Marine Holding Tank | B428

    Introducing the 36 Gallon Marine Holding Tank by One Clarion. This portable tank is designed specifically for marine use, making it the perfect solution for boat owners. With its rectangular shape and above ground usability, this tank is easy to...

    $373.57
    Add to Cart
  • An image of a 22 Gallon RV Holding Tank | RV99H

    36 Gallon Marine Fresh Water Tank | B383

    Introducing the 36 Gallon Marine Fresh Water Tank by One Clarion. This portable tank is specifically designed for marine use, making it perfect for boating and other water activities. With its rectangular shape and above ground usability, it offers...

    $408.72
    Add to Cart
  • An image of a 25 Gallon RV Holding Tank | RV98H

    36 Gallon Marine Holding Tank | B383

    Introducing the 36 Gallon Marine Holding Tank by One Clarion. This portable tank is specifically designed for marine use, making it the perfect solution for your boating needs. With its rectangular shape and above ground usability, this tank is both...

    $408.72
    Add to Cart
  • An image of a 29 Gallon Marine Fresh Water Tank | B423

    36 Gallon Marine Fresh Water Tank | B340

    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, allowing you to...

    $397.67
    Add to Cart
  • An image of a 29 Gallon Marine Holding Tank | B423

    36 Gallon Marine Holding Tank | B340

    Introducing the 36 Gallon Marine Holding Tank by One Clarion. This portable tank is designed specifically for marine use, making it the perfect solution for boat owners. With its rectangular shape, it fits easily into tight spaces and can be conveniently...

    $397.67
    Add to Cart
  • An image of a 22 Gallon Marine Fresh Water Tank | B473

    36 Gallon Marine Fresh Water Tank | B330

    Introducing the 36 Gallon Marine Fresh Water Tank by One Clarion! This portable tank is perfect for marine enthusiasts who need a reliable and convenient water storage solution. With its rectangular shape and above ground usability, this tank is designed...

    $421.77
    Add to Cart
  • An image of a 22 Gallon Marine Holding Tank | B473

    36 Gallon Marine Holding Tank | B330

    Introducing the 36 Gallon Marine Holding Tank by One Clarion. This portable tank is designed specifically for marine use, making it the perfect solution for boat owners. With its rectangular shape and above ground usability, this tank is easy to...

    $421.77
    Add to Cart
  • An image of a 135 Gallon RV Fresh Water Tank | B300

    36 Gallon Marine Fresh Water Tank | B254

    Introducing the 36 Gallon Marine Fresh Water Tank by One Clarion. This portable tank is specifically designed for marine use, making it perfect for boating and other water activities. With its rectangular shape, it offers a space-saving solution while...

    $373.57
    Add to Cart
  • An image of a 135 Gallon Marine Fresh Water Tank | B300

    36 Gallon Marine Holding Tank | B254

    Introducing the 36 Gallon Marine Holding Tank by One Clarion. This portable tank is specifically designed for marine use, making it the perfect solution for your boating needs. With its rectangular shape, it offers a space-efficient design that fits...

    $373.57
    Add to Cart
  • An image of a 36 Gallon Marine Holding Tank | B428

    36 Gallon Marine Fresh Water Tank | B158

    The 36 Gallon Marine Fresh Water Tank by One Clarion is a rectangular-shaped portable tank designed for above ground use. This tank is made of polyethylene material and comes in a natural white color. It measures 30 1/2" in length, 21 1/2" in width, and...

    $373.57
    Add to Cart
  • An image of a 105 Gallon RV Fresh Water Tank | B427

    36 Gallon Marine Holding Tank | B158

    The 36 Gallon Marine Holding Tank by One Clarion is a rectangular-shaped, portable tank designed for above ground use. This tank is made of durable polyethylene material and comes in a sleek black color. It measures 30 1/2" in length, 21 1/2" in width,...

    $373.57
    Add to Cart
  • 36 Gallon RV Water Tank W-531. Technical drawing of a polyethylene water tank designed for your rv.

    36 Gallon RV Water Tank W-531

    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 36 Gallon RV Water Tank, Part# W-531, is engineered to meet the requirements of mobile water...

    MSRP: $233.27
    $221.79
    Add to Cart
  • 36 Gallon RV Water Tank W-503. Technical drawing of a polyethylene water tank designed for your rv.

    36 Gallon RV Water Tank W-503

    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 36 Gallon RV Water Tank, Part# W-503, is engineered to meet the requirements of mobile water...

    MSRP: $220.31
    $209.47
    Add to Cart
  • 36 Gallon RV Water Tank W-469. Technical drawing of a polyethylene water tank designed for your rv.

    36 Gallon RV Water Tank W-469

    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 36 Gallon RV Water Tank, Part# W-469, is engineered to meet the requirements of mobile water...

    MSRP: $207.36
    $197.15
    Add to Cart
  • 36 Gallon RV Water Tank W-454. Technical drawing of a polyethylene water tank designed for your rv.

    36 Gallon RV Water Tank W-454

    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 36 Gallon RV Water Tank, Part# W-454, is engineered to meet the requirements of mobile water...

    MSRP: $298.07
    $283.39
    Add to Cart
  • 36 Gallon RV Water Tank W-3. Technical drawing of a polyethylene water tank designed for your rv.

    36 Gallon RV Water Tank W-3

    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 36 Gallon RV Water Tank, Part# W-3, is engineered to meet the requirements of mobile water...

    MSRP: $207.36
    $197.15
    Add to Cart
  • 36 Gallon Marine Water Tank MW-531. Technical drawing of a polyethylene water tank designed for marine vessels.

    36 Gallon Marine Water Tank MW-531

    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 36 Gallon Marine Water Tank, Part# MW-531, is engineered to meet the requirements of mobile...

    MSRP: $503.25
    $478.48
    Add to Cart
  • 36 Gallon Marine Water Tank MW-503. Technical drawing of a polyethylene water tank designed for marine vessels.

    36 Gallon Marine Water Tank MW-503

    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 36 Gallon Marine Water Tank, Part# MW-503, is engineered to meet the requirements of mobile...

    MSRP: $334.42
    $317.96
    Add to Cart
  • 36 Gallon Marine Water Tank MW-469. Technical drawing of a polyethylene water tank designed for marine vessels.

    36 Gallon Marine Water Tank MW-469

    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 36 Gallon Marine Water Tank, Part# MW-469, is engineered to meet the requirements of mobile...

    MSRP: $398.69
    $379.07
    Add to Cart
  • 36 Gallon Marine Water Tank MW-3. Technical drawing of a polyethylene water tank designed for marine vessels.

    36 Gallon Marine Water Tank MW-3

    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 36 Gallon Marine Water Tank, Part# MW-3, is engineered to meet the requirements of mobile...

    MSRP: $377.57
    $358.99
    Add to Cart
  • 36 Gallon RV Holding Tank H-616. Technical drawing of a polyethylene holding tank designed for your rv and camper.

    36 Gallon RV Holding Tank H-616

    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 36 Gallon RV Holding Tank, Part# H-616, is engineered to meet the requirements of mobile...

    MSRP: $246.23
    $234.11
    Add to Cart