Putting bathroom and utility sink in garage-help!

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Hi everyone, this is my first post. I've tried searching this site for answers (I do like the site) but I guess I'm a dumb a** when it comes to search. I am putting a bathroom in my garage, Outside of the interior bathroom wall, I also want to add a utility sink.
I'm concerned about how I'm tying in the sinks. Am I allowed to tie them into the 3" stack? sanitee or upright combo? See pic please.
Or is it all wrong because it's upstream from the toilet? I'm freaking out.
I want to make sure I get it right for the inspector. I'm not a pro, , just working on my own place and hope someone
can offer their thoughts, or suggested fixes in laymans terms. Thank you all.
bath layout 2.jpg

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In Seattle, we use the 2018 UPC code with Washington state amendments with some seattle/king co specific amendments (some unwritten even... fun) thrown on top of that...

In general every fixture requires a trap to keep sewer gases from escaping into your living space. To protect the trap from siphoning, every fixtures trap must be vented (properly). Your drawing sort of indicates that you're attempting to put together a Horizontal Wet vented bathroom which is good.. However, ONLY bathroom fixtures may be included in that system. The utility sink is not considered a bathroom fixture and must not travel through that drain/vent system, but can tie in downstream. I find its generally still less work and fittings to go ahead and run the 2 drains separate and parralel til they can tie in downstream.

Assuming this garage is located on a property with a home that already has plumbing.. The vent only has to meet the requirements of the DFU's / drainage fixture units of the fixtures its venting which is 2". Each of the separate branches needs a cleanout that serves the entire run. So 3" up to the bathroom sink for that run and 2" at the utility sink for that run.

Hey, wait a minute.

This is awkward, but...

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