Why Do Your Drains Bubble When Flushing Toilets?

Most homeowners want their plumbing to run smoothly and with as little drama as possible. A well-designed home plumbing system should function this way most of the time. Using one fixture or flushing a toilet shouldn't affect drains or fixtures elsewhere in the home, and it's usually a warning sign when this isn't the case.

One common issue is bubbling or water level fluctuations whenever you flush a toilet. For example, if flushing a bathroom upstairs in your home causes a downstairs toilet to bubble, then it's likely that you have an issue you need to address. Ignoring these signs can lead to more costly repairs in the future and may eventually result in water damage due to drain backups.

Why Do Drains Bubble?

It should come as no surprise that drains bubble when gas escapes through the water. You'll typically experience this in toilets since there's almost always some water sitting in the bottom of the bowl. Bubbling may be less apparent in showers or sinks since the water in the p-trap is out of sight. In these cases, you might hear gurgling or bubbling when running the water.

When everything is functioning correctly, gases escape your plumbing through a vent stack. You can usually find this pipe somewhere in your basement and trace it right up to your roof. Instead of bubbling out through your drains, this pipe allows gas to escape into the outside environment. When you hear consistent bubbling from your plumbing, it usually indicates a problem with this system.

However, venting problems do more than just release waste gases into your home and cause annoying noises. Air must be able to escape your drain pipes in order for water to flow smoothly. If air can't get out, your drains may begin to run slowly. When the problem becomes bad enough, your drainpipes may not run at all or even back up into your home.

What Causes Vent Issues?

Like many plumbing issues, it all comes down to clogs. Your plumbing air vents carry air instead of water, but other than that, they're no different from any other pipe in your home. These vents are particularly susceptible to clogs because they typically exist near the top of your house. Debris from storms and even rodents can enter your vent pipes, creating clogs that may back the whole system up.

Depending on the severity of the issue and the design of your vent system, you may need a professional plumber to assess and repair the problem. Most professionals will use an inspection camera to check your vents and confirm the location of any obstructions. If they don't find one, they'll know that the problem may lie elsewhere, such as a clogged house drain or sewer line.

Your home's vent pipes are a critical part of its sewage waste disposal system, and so you should never ignore potential issues with them. By dealing with the problem now, you can help yourself avoid an expensive mess in the future. Contact a local plumber to learn more.