Kitchens – Should our kitchen sink vent through the roof

As Ecnerwal indicated, there is no problem as far as fixture units for a sink and washer, but there may be more to this than what has been presented. Exactly what is the vent the sink is attached to venting? And where? Same floor or lower floor? Depending on what is being vented, you could be exceeding the allowable wet vent capacity.

Also, if the vent is for fixtures on a different level, you could have a problem, depending on what code is in effect. Some codes only allow vertical wet vents where all fixtures involved are on the same level. 2 feet of wet vent is not nearly as bad as 10 feet of wet vent.

Using a santee instead of a vent tee was not the best choice. Of course it will work fine, but someone could claim the baffle is preventing proper cleanout access. I'd say it is more of a technical violation than a real problem.

Not knowing what is being vented through the sink drain and not knowing what code is in effect, the only real advice I can give is the same as Ecnerwal: Check with your local authority having jurisdiction.

Does your jurisdiction allow Air-Admittance Valves (aka AAVs or Studor vents)? If it does, this would eliminate the need for an external vent.