I had a pipe dripping in basement from a bathroom sink drain. He did not trouble shoot the problem , just wrote up a $1800 estimate. So I did . Found out that it only drips when other users of water (washer) example going at the same time. What it turned out to be half clogged pipe leading to main drain. I removed the clean out plug and snaked it, problem solved. Good news is learned a lot about my plumbing. Contract # 051089