Back in January I told my husband I needed a pantry. A whole lot of money later we have a new powder room, a new laundry/mudroom and a big island in the kitchen, as well as the pantry. We've passed Electrical final inspection and I thought the plumbing final would also be no problem. Unfortunately, the inspector said our powder room sink is draining too slowly. Its all new plumbing so we know its not a clog.

The Kohler sink is one without an overflow. The drain thingy in the sink is just a strainer grid - it can't be used to keep water in this sink. The tailpiece came with this drain thingy (from Westbrass). I'm assuming its for no overflow sinks since it can't be closed.

My contractor thinks the problem is the vacuum since there isn't an overflow. The plumber said the same. Kohler tech support said I should have used a Kohler one and its not their problem.

I'm wondering if anyone else has run into this problem with the no-overflow sinks or vessel sinks (and how did you solve it?) Any ideas are so very appreciated!!