Even though it’s an ADU, I think 20 inches is just too small for a sink. Have you considered using a small dishwasher? There are compact models from 18-21 inches.

My sink is 21.5" and I'm glad it is not any smaller. How often will this space be used and by whom? If only one person a tiny dishwasher is fine. But for more than one person they really drive me up the wall. 15" cabinets with drawers really drive me up the wall too. They hold towels and random tuppeware. Not a great use of space.

Interior dimensions of 20 wide x 18 front to back is more than adequate for every piece of kitchen cookware you have. Test them if you don't believe that. 30 and 36" sinks are a total waste of counter space in this size kitchen. Make a box with those dimensions to test.

@njay and @Kendrah The original plan was an 18" but i found a smoking hot deal on a 24" bosch 800 series that i put into my actual house, freeing up my 4 year old (still in good shape) other bosch 800 dishwasher... so it'd be an unnecessary $500 expense to buy a 18". I am debating that option though as my sister could have my bosch.

i agree 15" drawers kind of suck but a doored cabinet that size is pretty worthless too and only holds baking pans. I didn't want to eat up any more of the "living room" room area though, its already getting tight. drawers could hold cooking utensils on top, ziplocks middle and small pots and pans bottom i guess. i agree though, its small. my thought it pull it out and put it in my laundry room (its basically the right size to fit between my washer and dryer.)

I plan to rent it out long termish. i'd assume a single person or perhaps a couple living in it.

@dan1888 i agree that 36 is too big. i'll find a 20" box to get a better idea. the sinks are more 16x18 (interior dimensions of the sink) that would fit.

thank you

Your 2D layout shows a 24" base cab. That is likely to take a sink with 21" interior by 18" listed as a 24" sink. If you undermount it the side lips of the sink can rest on the sides of the cabinet.

IMO the right size sink I have even smaller ones back to back in my catering kitcehn I think storge is a bigger deal especailly since you have a DW IMO even smaller and a bigger drawers.IMO the space is actually huge for an ADU so why not do true pullout pantries on the frdge wall and then no big deal about storage . It would be interesting to see the whole layout and how the smells and noise from a workshop will be handled and the entry . Where I live you need all kinds of permits to do living space above garages or workshops.

I have a single sink but it has a drainboard going over my dishwasher. PERFECT for what I need in a small kitchen. I like my 15" drawer as it is to the right of the sink and holds larger seldom used/specialty utensils, dish cloths and towels, kitchen wrap, foil etc. Perfect size for all those type of items that need a home.

Unless you're planning on short-term rentals, I'd do a bigger sink. It looks like you have drawers on the adjacent wall, so I'd ditch the skinny drawer stack in favor of a wider sink base.