There are a few ways to fix a leak in a metal gutter joint. You can use caulk, sealant, or even simple duct tape to patch it up. If the leak is bigger, you might need to replace the entire gutter system.

The first step is to find the source of the leak. Once you have located the source, clean it with a wire brush then use a sealant to fix it. If you are unable to fix the leak yourself, hire a professional to do it for you.