NW Conversions 20 Gallon Wheel Well Water Tank - Centered (SP-C-20)

Only 11 inches deep. The tank to buy when the aisle matters more than the last four gallons.

Depth is the spec that decides this one. At 11" it is the slimmest full-length centered tank NW Conversions offers — two inches shallower than the 24 gallon, five shallower than the 36. In a 144" wheelbase van where every inch of walkway is contested, those two inches are worth more than the four gallons you gave up.

Twenty gallons is a realistic weekend-to-midweek capacity for two people using a sink and an outdoor shower. Full, it adds about 190 lb.

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

• Buy the SP-C-20 if aisle width is your binding constraint and you want a centered, side-agnostic tank.
• Buy the SP-C-24 if you can spare two more inches of depth for four more gallons.
• Buy the SP-DU-19 if you want to give up no width between the wheel wells at all — it goes tall and narrow instead.

Confirmed fitment

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) SP-C-20 20 gallon rotomolded tank
• Fittings, hose and mounting hardware sold separately

Installing it: what actually happens

The slim section is the whole point, so protect it: do not sandwich the tank between a cabinet carcass and the wall with no gap. Polyethylene creeps under sustained load, and a tank squeezed between two hard faces will slowly take on their shape.

Leave a quarter inch of relief on each side and let the straps do the holding.

• Leave a relief gap either side — do not clamp the tank between cabinet and wall.
• Bench-drill the ports you need with a 2-1/8" hole saw.
• Ports at both ends means you can flip it to suit the pump.
• Continuous base support along the 46.5" length.

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 20 gallons is about 167 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.

Is 20 gallons enough?

For two people with a sink, a kettle and an outdoor shower we see four to six days between fills. Add an indoor shower and it becomes two to three. If you boondock for a week at a time, pair this with an undercarriage tank rather than buying a deeper interior tank.

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.