POST WRITTEN FEBRUARY 27, 2021

Sink planning! I wrote down many thoughts years ago, here they are:

hand washing, brush washing - doesn’t need to be potable
disposal: mesh sink catch for paint? or punch holes in an old can bottom - disposable :) another use for plastic tubs?? also plug
pay for metal (not pvc) piping if you want it to last (edit: ehhhhh...? don’t remember where/why i read this)
multiple 5gals that you can switch out instead of a permanent tank. easy to have a few, or use them for other stuff if needed. fixed amount of new water/used water.
alternative: two water tanks (would need precise sizing) and exterior port for filling/draining. this could get tricky with paint water - sludge WILL accumulate. Could do 5gal used, water tank fresh, and just stay careful of how full the used one is? (yes!)
fittings: http://terrylove.com/forums/index.php?threads/hose-port-on-a-gravity-fed-plastic-tank.18198/
pretty, expensive water bottles and crocks for drinking water: http://foryourwater.com/category/FYWBPAFREEWB.html
find port hardware like this -excellent description of low-use water system with options for manual jug or garden hose filling http://fynyth.blogspot.com/2015/01/off-grid-water-in-my-tiny-house.html
pot filler faucet

Now, revisiting the whole plan, here’s what we’ve decided on:

Under-mount tank for fresh water. There’s plenty of room under the skirt of the truck, and very handy, sturdy L-brackets to hang an exterior tank from. I want to limit my water-carrying as much as possible, and this will save me valuable interior space.
5gal for used/brown water. I have room underneath for a second tank, but the paint sludge is going to be hard to clean out of a regular black-water tank. I’ll regularly have sludge and crusty junk that needs to dry out into a disposable material. Using the same 5gal buckets positioned right under the sink will make it easy to switch out buckets as needed to clean them. I’ll rarely have so much water going that I need to do that more than once I day (I hope!) This will also remind me to conserve water.
Mount a drawer slide to get the bucket out from under the sink. I have to lift full 5gal buckets occasionally and it’s rough stuff. The less maneuvering around hoses etc I have to do, the safer and easier the process will be.

I bought a faucet! It’s this one. It swivels, it doesn’t have knobs, and it has a maximum flow of 2.2 Gallons/Minute.
https://www.jesrestaurantequipment.com/bk-resources-bkf-dmb-8g-g.html
BK Resources BKF-DMB-8G-G - Low Lead Deck Base Faucet w/8 in Swing Spout
The pump and foot pedal I bought previously will serve as planned.
Some other hoses and elbows and thread adapters were required though.

The tank is a 30G fresh/gray water tank. It comes with 4 ports on the short edge. Scary aesthetic is the result of working at night, after “Real Work” hours.
A.A 30 Gallon RV Fresh/Gray Water Tank 34" x 18" x 12" - BPA Free (30 Gallon)
For filling the fresh water tank, we’ll need to pierce the metal skirt and install this fixture.

The sink basin has been installed for a while, but it didn’t have one of these things, so we got one with a basket strainer! Perfect for collecting paint bits ahead of the game. Might need a mesh version to swap out occasionally, but the bucket will be gross anyway, so I’m happy with this. Also an excellent lid.
{link for basket strainer product}
We also needed to reshape the countertop a little bit to fit against my ‘close-enough’ cabinet construction style. None of what I had put together was actually fixed all the way down - just a small wooden frame attached to the wall. The countertop and supporting vertical piece needed to be shoved back into place frequently after a trip on the road.

Sink Work