NW Conversions 28 Gallon Promaster Wheel Well Water Tank - Right (PM-R-28)

Cut for the ProMaster’s oversized wheel housing on the passenger side — no 3.5-inch riser needed.

The ProMaster’s wheel wells are noticeably larger than a Sprinter’s, which is why every Sprinter-profile tank in this range carries a note about needing 3.5" of elevation to clear them. This tank does not. It is contoured for the ProMaster housing on the passenger side, so it sits down against the arch as delivered.

Twenty-eight gallons in 48" of length, 14" deep and 20" tall. It is the tank to buy if your galley or cabinet run is on the passenger side and you want the water underneath it rather than opposite it.

Should you buy this tank, or a different one in the range?

• Buy the PM-R-28 if you have a ProMaster and the water goes on the passenger side.
• Buy the PM-L-28 for the driver-side offset.
• Buy the PM-C-28 if you want the centered, reversible version.
• Do not buy a Sprinter-profile tank for a ProMaster unless you are prepared to build a 3.5" riser under it.

Confirmed fitment

That gap on a Sprinter or Transit is not a fitment failure — it is spare volume. Fill it with closed-cell foam so the tank cannot move and the arch does not sweat.

Specifications

These tanks are not pressure vessels. They must be vented to atmosphere — a sealed tank will balloon on a hot day and collapse inward when the pump draws it down.

What ships to you

• (1) PM-R-28 28 gallon rotomolded tank
• Fittings, hose and mounting hardware sold separately

Installing it: what actually happens

The ProMaster’s flat, wide floor makes this an easier install than the equivalent Sprinter job — you get a genuinely flat base to build a pan on rather than a set of deep ribs to bridge.

Twenty inches of height is the real constraint. Check it against your bed platform height before you order, particularly on a low-roof ProMaster.

• Measure your bed platform height against the tank’s 20" before ordering.
• The two 1/2" ports arrive open; the 1.5" ports are spun closed and need drilling.
• Bench-drill with a 2-1/8" hole saw, deburr, rinse, dry.
• Weight goes low and outboard — keep the opposite side loaded so the van sits level.

Questions we get asked about this part

Do I have to drill the ports myself?

On the wheel-well tanks the 1/2" NPT ports arrive open and ready to thread. The 1.5" ports are spun closed at the factory so you only open the ones your plumbing actually uses. Open them with a hole saw on the bench, before the tank goes anywhere near the van, and vacuum the shavings out. Plastic chips inside a fresh water tank are a mistake you only make once.

Does the tank need a vent?

Yes. It is designed to run unpressurized. Run a vent line from the top 1.5" port up above the maximum fill level and out through the floor or a body vent. Skip it and the tank will deform on a hot day, then pull its walls in when the pump runs.

How much weight am I adding to the van?

Water weighs roughly 8.34 lb per gallon, so 28 gallons is about 234 lb of payload once full, on top of the dry weight of the tank. Put that number in your build budget before you order rather than after — it is the most commonly forgotten figure in a van conversion.

Does this need the 3.5" riser that the Sprinter tanks need?

No. That note applies to Sprinter-profile tanks being fitted into a ProMaster. This tank is cut for the ProMaster arch, so it drops straight in.

Pairs well with

• Van water tanks and plumbing — the rest of the NW Conversions range

Sold and shipped by Campervan Parts R Us, the parts counter of Noke Van Co. — a working van conversion shop in Roanoke, Virginia. If you are unsure whether this fits your van, email us the year, model and wheelbase and we will check it against a build sheet before you order.