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

  • 15 Gallon RV Water Tank W-366. Technical drawing of a polyethylene water tank designed for your rv.

    15 Gallon RV Water Tank W-366

    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 15 Gallon RV Water Tank, Part# W-366, is engineered to meet the requirements of mobile water...

    MSRP: $116.64
    $110.90
    Add to Cart
  • 15 Gallon RV Water Tank W-355. Technical drawing of a polyethylene water tank designed for your rv.

    15 Gallon RV Water Tank W-355

    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 15 Gallon RV Water Tank, Part# W-355, is engineered to meet the requirements of mobile water...

    MSRP: $103.68
    $98.58
    Add to Cart
  • 15 Gallon RV Water Tank W-327. Technical drawing of a polyethylene water tank designed for your rv.

    15 Gallon RV Water Tank W-327

    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 15 Gallon RV Water Tank, Part# W-327, is engineered to meet the requirements of mobile water...

    MSRP: $116.64
    $110.90
    Add to Cart
  • 15 Gallon RV Water Tank L-3. Technical drawing of a polyethylene water tank designed for your rv.

    15 Gallon RV Water Tank L-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 15 Gallon RV Water Tank, Part# L-3, is engineered to meet the requirements of mobile water...

    MSRP: $116.64
    $110.90
    Add to Cart
  • 15 Gallon Marine Water Tank MW-543. Technical drawing of a polyethylene water tank designed for marine vessels.

    15 Gallon Marine Water Tank MW-543

    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 15 Gallon Marine Water Tank, Part# MW-543, is engineered to meet the requirements of mobile...

    MSRP: $346.52
    $329.47
    Add to Cart
  • 15 Gallon Marine Water Tank MW-489. Technical drawing of a polyethylene water tank designed for marine vessels.

    15 Gallon Marine Water Tank MW-489

    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 15 Gallon Marine Water Tank, Part# MW-489, is engineered to meet the requirements of mobile...

    MSRP: $185.41
    $176.28
    Add to Cart
  • 15 Gallon Marine Water Tank MW-366. Technical drawing of a polyethylene water tank designed for marine vessels.

    15 Gallon Marine Water Tank MW-366

    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 15 Gallon Marine Water Tank, Part# MW-366, is engineered to meet the requirements of mobile...

    MSRP: $246.93
    $234.77
    Add to Cart
  • 15 Gallon Marine Water Tank MW-355. Technical drawing of a polyethylene water tank designed for marine vessels.

    15 Gallon Marine Water Tank MW-355

    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 15 Gallon Marine Water Tank, Part# MW-355, is engineered to meet the requirements of mobile...

    MSRP: $182.38
    $173.40
    Add to Cart
  • 15 Gallon Marine Water Tank MW-328. Technical drawing of a polyethylene water tank designed for marine vessels.

    15 Gallon Marine Water Tank MW-328

    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 15 Gallon Marine Water Tank, Part# MW-328, is engineered to meet the requirements of mobile...

    MSRP: $300.67
    $285.87
    Add to Cart
  • 15 Gallon Marine Water Tank MW-327. Technical drawing of a polyethylene water tank designed for marine vessels.

    15 Gallon Marine Water Tank MW-327

    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 15 Gallon Marine Water Tank, Part# MW-327, is engineered to meet the requirements of mobile...

    MSRP: $205.77
    $195.65
    Add to Cart
  • 15 Gallon Marine Water Tank ML-3. Technical drawing of a polyethylene water tank designed for marine vessels.

    15 Gallon Marine Water Tank ML-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 15 Gallon Marine Water Tank, Part# ML-3, is engineered to meet the requirements of mobile...

    MSRP: $231.73
    $220.33
    Add to Cart
  • 15 Gallon RV Holding Tank H-236 . Technical drawing of a polyethylene holding tank designed for your rv and camper.

    15 Gallon RV Holding Tank H-236

    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 15 Gallon RV Holding Tank, Part# H-236, is engineered to meet the requirements of mobile...

    MSRP: $181.44
    $172.50
    Add to Cart
  • 15 Gallon RV Holding Tank H-229 . Technical drawing of a polyethylene holding tank designed for your rv and camper.

    15 Gallon RV Holding Tank H-229

    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 15 Gallon RV Holding Tank, Part# H-229, is engineered to meet the requirements of mobile...

    MSRP: $116.64
    $110.90
    Add to Cart
  • 15 Gallon RV Holding Tank H-131. Technical drawing of a polyethylene holding tank designed for your rv and camper.

    15 Gallon RV Holding Tank H-131

    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 15 Gallon RV Holding Tank, Part# H-131, is engineered to meet the requirements of mobile...

    MSRP: $155.52
    $147.87
    Add to Cart
  • 15 Gallon RV Holding Tank H-79 (OR). Technical drawing of a polyethylene holding tank designed for your rv and camper.

    15 Gallon RV Holding Tank H-79 (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 15 Gallon RV Holding Tank, Part# H-79 (OR), is engineered to meet the requirements of mobile...

    MSRP: $155.52
    $147.87
    Add to Cart
  • An image of a 20 Gallon Marine Holding Tank | B164

    16 Gallon RV Fresh Water Tank | RVB526

    The 16 Gallon RV Fresh Water Tank by One Clarion is a must-have for any RV owner. This rectangular tank is designed to be portable, making it easy to transport and use wherever you go. With its above ground environment, you can rest assured that your...

    $190.80
    Add to Cart
  • An image of a 14 Gallon Marine Fresh Water Tank | B238

    16 Gallon RV Fresh Water Tank | RVB106

    The 16 Gallon RV Fresh Water Tank by One Clarion is a must-have for any RV owner. This rectangular tank is designed to be portable, making it easy to transport and use wherever you go. With its above ground environment, you can rest assured that your...

    $207.87
    Add to Cart
  • An image of a 8 Gallon Marine Holding Tank | B270

    16 Gallon RV Holding Tank | RV7H

    Introducing the 16 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...

    $246.04
    Add to Cart
  • An image of a 5 Gallon PP Ronco White Rectangular Open Top Tank | 18X4X18PP

    16 Gallon RV Holding Tank | RV58H

    Introducing the 16 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 environment, you can easily install and...

    $258.09
    Add to Cart
  • An image of a 5 Gallon PE Ronco White Rectangular Open Top Tank | 18X4X18PE

    16 Gallon RV Holding Tank | RV57H

    Introducing the 16 Gallon RV Holding Tank by One Clarion. This rectangular tank is designed specifically for RV use, making it portable and easy to transport. With its above ground placement, you can conveniently access and maintain the tank without any...

    $258.09
    Add to Cart
  • An image of a 7 Gallon RV Fresh Water Tank | RVB271

    16 Gallon RV Holding Tank | RV29H

    Introducing the 16 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 a capacity of 16 gallons, this tank is suitable for above...

    $292.23
    Add to Cart
  • An image of a 18 Gallon Marine Fresh Water Tank | B412

    16 Gallon Marine Fresh Water Tank | BOAT36W

    The 16 Gallon Marine Fresh Water Tank offered by One Clarion is a versatile and portable solution for your marine water storage needs. With its rectangular shape and above ground usability, this tank is designed to fit seamlessly into your boat or marine...

    $246.04
    Add to Cart
  • An image of a 18 Gallon Marine Holding Tank | B412

    16 Gallon Marine Holding Tank | BOAT36W

    The 16 Gallon Marine Holding Tank by One Clarion is a rectangular-shaped tank that is designed for portable use in above ground environments. This tank is made from high-quality polyethylene material and comes in a sleek black color. It is not designed...

    $246.04
    Add to Cart
  • An image of a 25 Gallon Marine Fresh Water Tank | B163

    16 Gallon Marine Fresh Water Tank | B526

    The 16 Gallon Marine Fresh Water Tank from One Clarion is a rectangular, portable tank designed for above ground use. Made from polyethylene in a natural white color, this tank is 26" in length, 14" in width, and 11" in height. It is not designed for...

    $280.18
    Add to Cart
  • An image of a 30 Gallon Marine Fresh Water Tank | B162

    16 Gallon Marine Holding Tank | B526

    The 16 Gallon Marine Holding Tank offered by One Clarion is a versatile and portable solution for your marine waste management needs. With its rectangular shape and above ground usability, this tank is designed to fit seamlessly into your boat or marine...

    $280.18
    Add to Cart
  • An image of a 30 Gallon Marine Fresh Water Tank | B112

    16 Gallon Marine Fresh Water Tank | B500

    Upgrade your marine vessel with the 16 Gallon Marine 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 37...

    $246.04
    Add to Cart
  • An image of a 16 Gallon Marine Fresh Water Tank | B111

    16 Gallon Marine Holding Tank | B500

    The 16 Gallon Marine Holding Tank by One Clarion is a rectangular-shaped, portable tank designed for above ground use. This tank is not pressurized, making it a safe and reliable option for marine applications. The tank is made from high-quality...

    $246.04
    Add to Cart
  • An image of a 30 Gallon Marine Holding Tank | B112

    16 Gallon Marine Fresh Water Tank | B399

    The 16 Gallon Marine Fresh Water Tank by One Clarion is the perfect solution for your portable marine water needs. This rectangular tank is designed for above ground use and is made from high-quality polyethylene material in a natural white color. The...

    $326.38
    Add to Cart
  • An image of a 16 Gallon Marine Holding Tank | B111

    16 Gallon Marine Holding Tank | B399

    The 16 Gallon Marine Holding Tank offered by One Clarion is a versatile and portable solution for your marine waste management needs. With its rectangular shape, this tank is designed to fit seamlessly in your boat or marine vessel. Made from durable...

    $326.38
    Add to Cart
  • An image of a 40 Gallon Marine Holding Tank | B221

    16 Gallon Marine Fresh Water Tank | B398

    Introducing the 16 Gallon Marine Fresh Water Tank by One Clarion. This portable tank is designed specifically for marine use, making it the perfect solution for storing and transporting fresh water on your boat or yacht. With a rectangular shape and a...

    $327.38
    Add to Cart
  • An image of a 43 Gallon Marine Fresh Water Tank | B220

    16 Gallon Marine Holding Tank | B398

    The 16 Gallon Marine Holding Tank by One Clarion is a versatile and portable solution for your marine waste management needs. With its rectangular shape, this tank is designed to fit seamlessly in your boat or marine vessel. Made from durable...

    $327.38
    Add to Cart
  • An image of a 58 Gallon RV Fresh Water Tank | RV60W

    16 Gallon Marine Fresh Water Tank | B373

    Upgrade your marine vessel with the 16 Gallon Marine 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...

    $281.18
    Add to Cart