There are a few ways to tell if your drain is blocked. One way is to pour a pot of boiling water down the drain and see if it clears up. If the boiling water doesn't work, you can try using a plunger. And if that doesn't work, you can try using a snake to clear the clog.

The water is not passing through the drain. How do you know if your drain is blocked? One way to tell if your drain is blocked is to pour a pot of boiling water into it and see whether the water bubbles up and flows down the drain. If it doesn't, then there's a good chance that the drain is blocked. Another way to test for a blockage is to pour a cup of baking soda down the drain and then follow it with a cup of vinegar. If the baking soda and vinegar mixture fizzes up, then that means that there's a blockage somewhere in the pipe.