We are having this same problem. We had a new kitchen faucet installed about 6 months ago - single lever - and everything was great until a few weeks ago. Then it started. When we turn on the cold water, the first blast is soapy. After we let it run a few seconds it seems to clear out. What could be causing this? (We are on city water, and we have always had soapy water come up from the drain when we are using the dishwasher or the washing machine.)