I'd rate this as Zero stars if i could. They pilot light on my water heater would not stay lit. So the plumber from Cost came to my house to diagnose on a Monday. He said that I need a new gas valve and his boss would call me back on Tuesday to set up the appointment to install. I did not receive a call Tuesday or Wednesday and then I called Cost back on Thursday. The person I spoke with said they would research and call me right back. They did not call me back Thursday or Friday, and I called them back on Saturday. So finally they came back a week later (the following Monday) to install the gas valve. About 2 hours after the installation, the pilot went out again. I had my home warranty company company call Cost to come back out and they refused. In the end, I needed a liner for my flue. So in addition to the horrible customer service and responsiveness, this was totally misdiagnosed by Cost. Do not use these guys, even if you have 3 feet of water in your basement. They are the worst!!