Toilet water moves when windy due to the pressure difference between the inside and outside of your house. This pressure difference can be caused by a variety of factors, including:

Wind pressure

The wind creates a pressure difference between the inside and outside of your house. This causes air to flow from an area of high pressure (outside) to an area of low pressure (inside). As air flows into your house, it displaces the air inside, which makes the pressure inside lower than outside. The reverse happens when the wind stops blowing.

Air-conditioning systems

Air-conditioning systems can create a similar effect as wind when they are operating. When they’re turned on, they create a low-pressure zone around them that sucks in air from other parts of your home or yard. This can cause water to move around in toilets and sinks as well as other plumbing fixtures such as faucets and showers.

Heat pumps/furnaces

If you live in a region where winter temperatures drop below freezing but summer temperatures rise above 80 degrees Fahrenheit (26 degrees Celsius), then you might have heat pumps or furnaces installed in your home that use electricity to move heat from one place to another — either from outside into.

Last modified: October 2, 2022