Eli5 when it’s windy outside why does the water in toilets swish a little bit?
In: 1241
It doesn’t, you’re just imagining it.
Just kidding, the other folks talking about the vent are correct.
It doesn’t, you’re just imagining it.
Just kidding, the other folks talking about the vent are correct.
It doesn’t, you’re just imagining it.
Just kidding, the other folks talking about the vent are correct.
Somewhere in your building is a pipe that connects to open air. This is important for ensuring proper draining of the pipes when you flush/shower/use the sink. Anyway, this means outside air pressure does act on the waste water in your home. Wind is just air moving from higher pressure to lower pressure. Also velocity is inversely proportional to pressure. So when a gust of wind blows by that opening, it creates some negative pressure, which tries to suck water through your drain pipes. It doesn’t suck very hard, but enough to cause those little waves and ripples in your toilet bowl.
Somewhere in your building is a pipe that connects to open air. This is important for ensuring proper draining of the pipes when you flush/shower/use the sink. Anyway, this means outside air pressure does act on the waste water in your home. Wind is just air moving from higher pressure to lower pressure. Also velocity is inversely proportional to pressure. So when a gust of wind blows by that opening, it creates some negative pressure, which tries to suck water through your drain pipes. It doesn’t suck very hard, but enough to cause those little waves and ripples in your toilet bowl.
Somewhere in your building is a pipe that connects to open air. This is important for ensuring proper draining of the pipes when you flush/shower/use the sink. Anyway, this means outside air pressure does act on the waste water in your home. Wind is just air moving from higher pressure to lower pressure. Also velocity is inversely proportional to pressure. So when a gust of wind blows by that opening, it creates some negative pressure, which tries to suck water through your drain pipes. It doesn’t suck very hard, but enough to cause those little waves and ripples in your toilet bowl.
[The vent stack is open to the sky](https://i.imgur.com/U2RmGwF.jpg). Its primary purpose is to break siphons so draining water doesn’t empty toilet bowls and P-traps, which would allow sewer gas to come back up the drain.
But, localized differences in air pressure (“wind”) are able to pass through the vent, which jostles the water in the toilet bowl.
[The vent stack is open to the sky](https://i.imgur.com/U2RmGwF.jpg). Its primary purpose is to break siphons so draining water doesn’t empty toilet bowls and P-traps, which would allow sewer gas to come back up the drain.
But, localized differences in air pressure (“wind”) are able to pass through the vent, which jostles the water in the toilet bowl.
[The vent stack is open to the sky](https://i.imgur.com/U2RmGwF.jpg). Its primary purpose is to break siphons so draining water doesn’t empty toilet bowls and P-traps, which would allow sewer gas to come back up the drain.
But, localized differences in air pressure (“wind”) are able to pass through the vent, which jostles the water in the toilet bowl.
I grew up in the southeast and even with vents through the ceilings never experienced this until moving to the Midwest. Like I’ve been through several hurricanes up to and including Cat4 and never noticed the toilet water moving like this until 5 years ago living in the Midwest with crazy gusty winds all moving the same direction. It still creeps me out even knowing what the cause is.
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