This is an easily searchable answer: https://www.tripsavvy.com/washington-marijuana-smoking-regul...

https://www.thestranger.com/green-guide-spring-2018/2018/04/...

https://lcb.wa.gov/mj-education/know-the-law

it might or might not be a good idea to do some research before asking others to do research for you

Indeed, I'd sign up for that sociable experience. There used to be (in the pre-legalization days) speakeasy-type places you could go to smoke and enjoy; live music, fruit juice on tap, that kind of thing. But nowadays it is all but impossible to find, being made in many cases (at least on the west coast) explicitly illegal. Those places allowed a different kind of socialization that is still just as legitimate as a bar full of strangers talking about sports. Think collective artwork and experimental music. Some day...

I'm not sure on the details but just throwing out what I've seen in NY. Smoke shops around here seem to allow smoking indoors, I assume there are special provisions for that type of business.

There is also a bar around here that has a separate smoking room. They have a large air filtration system hanging from the ceiling in there, not sure if thats why they can get away with it. There is even a little door in the wall where they can serve drinks to you while you're in there.

I believe a separate room (sealed with automatic closing door) and an air extractor/scrubber is required for indoors usage. Where I live, you can offer a smoking section outdoors, but honestly, the air extractors are pretty cheap and help avoid adjacent non-smoking patrons from being bothered. They should be used both indoors and outdoors in my view.

Almost certainly regulations. There's a cafe/dispensary combination in Redmond, but all of the various parts are separated.

For one thing, since pot takes a long time to leave your system, police could probably pull over every single patron and they'd meet the legal definition of a marijuana DUI.