This material is very good at stopping leaks. I used it to stop a leak in the shower and then I used it to stop a leak in a water heater. I was amazed to see that the water heater leak was reduced by 75% after packing this stuff around the leak which was great because the plumber couldn't come to replace the water heater until a week later. The putty in the tin I received was still malleable and workable. Not difficult like some of the reviews I read say. The only drawback is that it is a very small can. I thought the amount sounded like a lot but it's very narrow so there really isn't that much in a very small glass. If you have a big job, like walking around the shower stall, buy a larger glass.