I hear a constant dripping sound behind bathroom sink. I shut the main valve and I still hear it. Help, should I call a plumber?

When you shut the main valve did you open a faucet downstairs as well opening the sink faucet in question? If not, shut the main again, drain the water and then tell us what you hear... if anything.

Mark

Hi, actually after about 10 or 15 minutes of shutting down valve it stopped. And the sound was more like slow running water. What do you think?

Doesn't sound good. Obviously you checked below to see if any water is present... right?

As a plumber I would have you do what I suggested at the first post... if noise stops immediately after you drain the pipes then you will most likely have an issue. If not, could be something else.

Can't hurt to poke a hole in the wall, under the sink and take a peek if you want.

Mark

My house is one story.. do you think I have a leak behind the sink? I had a plumbe come out 2 weeks ago to fix a clogged disposal and he ran a snake to unclogge it. Do you think it may have something to do with it? My house is only 4 yrs old.