Plumber’s putty is a substance used to make watertight seals between pipes and countertops. It will remain soft for a long while after it is applied, making it ideal for seals you will need to reverse. Because it does stay soft, you shouldn’t use plumber’s putty on pipes that will experience any amount of water pressure. The putty is fairly easy to use and can be wiped away if you make a mess. Here are some common places where plumber’s putty will come in handy.