To use sealing tape for water leaks, start by turning off the water supply to the affected area. Next, locate the source of the leak and clean the surface around it thoroughly with a dry cloth or sandpaper Next, locate the source of the leak and clean the surface around it thoroughly with a dry cloth or sandpapersealing tape for water leaks. Cut a piece of sealing tape slightly longer than the length of the leak and remove the backing paper. Apply the tape firmly over the leak, smoothing out any wrinkles or bubbles as you go. Finally, turn on the water supply slowly and check for any further leaks. If necessary, apply additional layers of sealing tape until the leak is completely sealed.