I replaced my bathroom sink with a new one, and the tailpiece & trap are new plastic pieces. Problem is the pipes fill up as the water runs from the tap until it begins to fill the sink bowl, and then very slowly drains. This never happened with the previous faucet. All the lines are clear, including the brass pipe in the wall. I've re-installed the tailpiece a few times thinking I blocked a vent with plumbers putty, but all is clear. Any ideas?

Fredrick Edwin

We installed a new shower during the same project, and the shower drain was moved. I guess it's possible that something in the installation has caused the drainage problem with the sink? The shower drains fine, as does the adjoining hall bath tub & sink which all go into the same main soil pipe. Shouldn't they also have aslow drain probelm? I'll snake the line just to be sure.