Since there has been 3 feet of snow on the roof the kitchen drains, dishwasher etc has been slow to not at all draining. I put a 100ft snake through the line but it seems clear.

The back end of the house (bathrooms) are draining fine.

Could it be anything other than the roof vent.

Yes most defiantly the Vent line could be clogged. We had quite a few here so far this winter. Snake out your roof sewer vent and maybe hot water after snaking out or just some hot water. Please be careful on snowy roof! The line sounds fine its vent clog

Signed 21 Boat

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Rainwood...

Go outside and see if the vent pipe sticking out the roof is covered with snow... If so, then you found issue.

Next, if possible, go inside the attic space to where this vent penetrates the roof... check to see if you see condensation/moisture near exterior... if so maybe good idea to try and heat the pipe/space up a bit with a heat gun or similar tool before going out on/near snowy roof... ok?

Anyway, check these things first... let us know what you find! Be careful!

MARK