My dishwasher drains through what appears to be a Johnson Tee, although I can't be sure exactly what is in the wall. The kitchen was remodeled in 2004 and passed Bellevue WA inspector then, but the vent is probably original, circa 1977.

When the dishwasher runs the exterior vent drizzles water down the side of the house. What is the likely problem, and can I fix it without ripping out the wall?

Thanks, --Andy

I would love to get inside thatwall. This vent and your plumbing should not be connevted. A dishwasher should be connected to your sink drain.