Eli5 when it’s windy outside why does the water in toilets swish a little bit?

Question

Eli5 when it’s windy outside why does the water in toilets swish a little bit?

In: 1241

Answer 1

Back draft from your roof vents.

All your plumbing has a roof vent attached to the system to aid in drainage. If air pressure is right it can make the standing water in your toilet “dance”.