How to find the overflow in a toilet

A good question came up in response to my hard to flush toilet blog post. How do you find the overflow in a toilet?

Find the overflow in your toilet

To find your toilet’s overflow, take the lid off the water tank. Inside the tank, take note of the water level. The easiest way to find the overflow is to imagine the water level going too high. Look for where the water would go. There’s something in the toilet’s tank expressly designed to drain off excess water if the level gets too high.

Probably the most common arrangement is a pipe or tube. This is especially true in toilets made relatively recently, since there aren’t many toilet-related patents still in force that manufacturers have to work around.

Older toilets sometimes do things a bit differently. I have one where the overflow is cast into the toilet body itself, rather than being a replaceable plastic part. Presumably this was how they worked around someone else’s patent when the toilet was new.

The overflow’s job is to divert water from the tank into the bowl in the events of that the tank fills up with too much water.

If you just can’t seem to find where the water would go, in a pinch, here’s how you can find out. Fill up an old milk jug with water and pour some water into the tank. Then watch where the water goes.

Now you found your toilet’s overflow.

Pouring a cup of vinegar into the overflow and letting it sit for a few hours is very good for your toilet, for what it’s worth.

Dave Farquhar

David Farquhar is a computer security professional, entrepreneur, and author. He has written professionally about computers since 1991, so he was writing about retro computers when they were still new. He has been working in IT professionally since 1994 and has specialized in vulnerability management since 2013. He holds Security+ and CISSP certifications. Today he blogs five times a week, mostly about retro computers and retro gaming covering the time period from 1975 to 2000.