I thought I’d order a custom-shaped black water tank for the Westy, considering the placement of the downpipe relative to the wheel well (the down pipe is forward of the wheel well). I sent my diagram off to six places, got 2 responses, both around $600 – much more than I had anticipated.

So back to the drawing board! A bit of playing around with some wooden boards made me realize that I could lose 3 inches to clear the wheel well, and still fit a big rectangular tank. My local supplier has a 21″ x 21″ x 11.25″ tank that can squeeze into the space – that’s 20 gallons!

I do lose some storage in the back. I used to keep dirty boots in the little alcove between the door and the old black water tank, but the new tank will come right to the threshold. But that’s not a bad tradeoff for the larger capacity.

(Cardboard mockup of a 20G black water tank.)

(Mockup of a 20G black water tank, showing the 3″ space to the left required to clear the wheel well.)