From a Master Plumber: Why is My Toilet Gurgling?

If your toilet gurgles when you flush it, common sense tells you that it isn’t burping at you. A toilet can’t burp, right? Well, in a way, it is burping. A gurgling or bubbling toilet usually means there is a blockage somewhere in the line. With nowhere else to go, air will form and try to escape from the easiest exit point – your toilet.

What can you do to fix a gurgling toilet? The first step in fixing any plumbing problem is to find the source of the problem – in this case, where the blockage is. In the case of a gurgling toilet, you’ll usually find a clog in one of two places.

Main Drain or Septic Tank

A bubbling toilet is usually a sign that your septic tank is full. If the tank is full and cannot drain out properly into the leach field, air will form and escape through your toilet. If your toilet has started gurgling and your other fixtures are draining slowly or even into each other, you will want to call a septic tank company as soon as possible. If your plumbing drains into a city sewer line, clogs or roots near the end of the line can also cause a gurgling toilet.

Blocked Vent

If your main vent line is blocked, a vacuum will form, impairing your drain line’s ability to function properly and causing air to escape through the toilet. Vent lines can become plugged by leaves and other debris, or an animal or bird nest. Ice can also block a vent pipe, although it is rare for ice to form because of the heat from a vent pipe.