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!
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

STRAPPING NOT INCLUDED. We suggest using stainless-steel or galvanized steel-slotted strapping with 1/4" riv-nuts to secure the tank to your van's undercarriage. Only use corrosion-resistant strapping, as the strapping will be exposed to moisture.

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 $20 vs buying separately!

Full Details of the Fresh Water Fittings Kit Add-On
Select this add-on with your tank purchase and save $20 vs buying separately!

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

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