SKU: 12746144903

Promaster Undermount Water Tank (15 Gallon)

Sale price$116.55 Regular price$129.50
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Ships within 48 hours · Estimated delivery Aug 1 - Aug 6

Promo Codes Available:

For Your Every Summer RSVP, with Code: SUMMER15

Description

Promaster Undermount Water Tank (15 Gallon)We are always striving for better space saving ideas, and this undercarriage tank is just the ticket! This tank is designed to fit snugly around your Promasters framed undercarriage; these tanks are the perfect solution for your off grid water requirements. Composed of high quality, BPA free, food grade approved linear low density polyethylene, this tank can also function as freshwater storage. We've created a complete Freshwater Fittings Kit that

We are always striving for better space-saving ideas, and this undercarriage tank is just the ticket! This tank is designed to fit snugly around your Promaster’s framed undercarriage; these tanks are the perfect solution for your off-grid water requirements.

Composed of high-quality, BPA-free, food-grade approved linear low-density polyethylene, this tank can also function as freshwater storage. We've created a complete Freshwater Fittings Kit that includes everything you need to turn this tank into an undermount freshwater reservoir. 

Complete your off-grid water management system by pairing this undermount tank with our 22 Gallon, or our 32 Gallon Promaster Wheel Well Water Tank. Worry less about water management, and spend more time adventuring!

Key Features & Benefits:

  • Save Space - Mount underneath your van chassis for extra storage room inside your van - passenger side only.
  • Perfect Fit - Designed to fit perfectly under the Promaster van, simply position the tank and attach with strapping, no need to make modifications.
  • Durable Design - This tank is tough; rest assured knowing your tank will hold up to exposure and the elements.
  • Multi-Purpose - Use this undermount tank for grey water storage, or bundle it with our Freshwater Fittings Kit and turn this tank into a freshwater reservoir.
  • BPA-Free and Food Grade Approved - These tanks are CSA approved and food grade certified for safe drinking water.
  • Fittings Kit Add-On Available - Save yourself the headache and multiple trips to the plumbing store when you bundle this tank with our Grey Water Fittings Kit or Fresh Water Fittings Kit!
  • Strapping Kit Add-On Available - Weather-resistant strapping crafted from heavy-duty 1/8" thick, 1 1/2" wide aluminum. Simple and secure! 
  • Compatible - This tank pairs well with our 22 Gallon and 32 Gallon Promaster Wheel Well Water Tanks.

Dimensions & Specifications:

Designed for the Ram Promaster 159" & 159" extended wheelbases.
NOT COMPATIBLE with the 118" or 136" wheelbase.

The tank can only be mounted on the PASSENGER SIDE of your van.
However, your drain hose can be routed to your drivers side if needed.

Tanks are made from linear low-density polyethylene.
Food grade CSA approved and BPA free - safe for freshwater use!

15 US Gallons / 56.7 Litres

45.5" x 13 3/8" x 8" (Length x Width x Height)

1 x 1 ¼" fill port (on right side)
1 x ¾" drain port (on right side)
2 x ½" vent ports (on left side, top of humps)
1 x ½" vent port (on front end, top of hump)
1 x ½" optional water-pump port for freshwater use (on front end, bottom corner)

All ports are NPT female-threaded.

Grey Water Fittings Kit Add-On:

  • 1x 1 ¼" PVC 90
  • 2x ¾" PVC 90
  • 1x ¾" PVC Ball Valve
  • 1x ¾" Nipple - 6" long
  • 1x ¾" Nipple - 4" long
  • 1x ¾" Nipple - 1 ½" long
  • 3x ½" Poly Adaptors
  • 1x ½" Poly Elbow
  • 1x ½" PVC Plug
  • 2x #20 Hose Clamps
  • 3x #8 Hose Clamps
  • 1x Roll of Teflon Tape
  • 5ft Fill Hose
  • 2ft ⅝" ID Vinyl Hose

Fresh Water Fittings Kit Add-On:

  • 1x 1 ¼" PVC 90
  • 2x ¾" PVC 90
  • 1x ¾" PVC Ball Valve
  • 1x ¾" Nipple - 6" long
  • 1x ¾" Nipple - 4" long
  • 1x ¾" Nipple - 1 ½" long
  • 3x ½" Poly Adaptors
  • 1x ½" Poly Elbow
  • 1x ½" PVC Plug
  • 2x #20 Hose Clamps
  • 2x #8 Hose Clamps
  • 1x Roll of Teflon Tape
  • 1x Fill Port
  • 5ft Fill Hose
  • 5ft ⅝" ID Vinyl Hose

Aluminum Strapping Kit Add-On:

  • 2x Heavy-Duty Aluminum Straps
  • Aluminum Hardware

More Information:

Wheel Well & Undermount Water Tank FAQ Sheet

Full Details of the Grey Water Fittings Kit Add-On
Select this add-on with your tank purchase and save $$ vs buying separately!

Full Details of the Fresh Water Fittings Kit Add-On
Select this add-on with your tank purchase and save $$ vs buying separately!

Full Details of the Aluminum Strapping Kit Add-On
Select this add-on with your tank purchase and save $$ vs buying separately!

Check out our Promaster Wheel Well Water Tank (22 Gallon)

Check out our Promaster Wheel Well Water Tank (32 Gallon)

Install Instructions:

Freshwater Fittings Kit Install Instruction
Grey Water Fittings Kit Install Instructions
Strapping Kit Install Instructions for Promaster 15 Gallon Water Tank (Passenger Side)

Shipping Notes
  • Free Standard Shipping on $100+ Orders to the USA.
  • Except Preorder products are shipped in 48 hours.
  • Delivery to the USA:
  1. Standard Shipping : 3-10 business days
  • If time is of the essence, please consider selecting expedited delivery for faster service.
Exchange/Return Notes
  • We offer a 30-day return/exchange service after receiving.
  • Final sale items are not eligible for returns or exchanges.
  • To process your return/exchange, please contact us at [email protected]
  • Please click here for more details>>> Return & Exchange Policy
SKU: 12746144903

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Reviewed in the United States on October 13, 2025
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