why does toilet water move when the wind blows

Why does toilet water move when the wind blows? You are likely to ask this question if you have ever noticed the water in the toilet starts moving around all mysteriously the moment the wind blows.

It is unclear how air currents link to the seemingly unconnected movement of water in toilets, but it has prompted some interesting speculation.

And it often makes people ask, “Why does the water in my toilet bowl move around when the wind blows?

The toilet water may move around due to the complex relationship between fluid dynamics, air pressure differences, and the design and ventilation of plumbing systems

Why Does Toilet Water Move When the Wind Blows?

toilet water movement in the wind

It has been observed by some individuals that during periods of strong wind, the water in their toilet bowl may exhibit some movement that may appear unusual.

The cause of this phenomenon is not immediately clear. This interesting event prompts inquiries regarding the correlation between air currents and water flow.

The truth is that there are a number of factors at play, which help answer,” Why does toilet water move when windy?”

Let’s find out more about it now: 

Ventilation System

ventilation system

In order to gain a better understanding of the movement of water in a toilet bowl during windy conditions, it is important to consider the impact of air pressure.

Residential plumbing systems typically include ventilation pipes that are connected to the drainage system.

These pipes play an important role in maintaining the air pressure balance within the plumbing system. This helps to ensure smooth water flow and prevent the accumulation of gases.

In certain weather conditions, it is possible for external factors such as strong winds to have an impact on the ventilation system and cause pressure fluctuations.

The movement of wind against the building may cause pressure differentials in the pipes, which could affect the water level and flow in the toilet bowl.

Fact: It is important to note that the wind's direction and intensity can directly impact the movement of toilet water. 

Bernoulli’s Principle and Airflow

bernoulli's principle and airflow

Bernoulli’s principle can offer valuable insights into the behavior of water in a toilet bowl when exposed to strong winds.

Bernoulli’s principle suggests a relationship between the speed of airflow and the pressure exerted by the air, where an increase in speed results in a decrease in pressure, and vice versa.

When the wind comes across a building, it can generate areas of high pressure on the side facing the wind and low pressure on the opposite side.

The air around the building tends to follow its contours and architecture, creating a flow pattern commonly referred to as the boundary layer.

The airflow pattern has an impact on the air pressure within the toilet bowl. 

An Important Consideration

On the windward side, the airflow moves at high speed, resulting in areas of lower pressure.

On the leeward side, the airflow moves at a lower speed, resulting in higher pressure. The pressure difference can have an impact on the air pressure inside the toilet bowl.

changes in air pressure

The movement of water in the toilet bowl can be attributed to the changes in air pressure.

When there is a strong gust of wind, it can cause a momentary decrease in air pressure within the toilet bowl due to the low-pressure area created near the building.

The change in air pressure can cause the water in the bowl to move or oscillate due to the external air pressure.

Fact: Bernoulli's principle can be used to understand how the pressure changes caused by airflow can impact the water in a toilet bowl. 

Stack Effect and Building Design

stack effect and building design

It is worth noting that the stack effect, which refers to the air movement within buildings, may also have an impact on the water flow in a toilet bowl.

The stack effect is a phenomenon that can be observed in buildings as a result of temperature variations between the inside and outside environments.

It is a well-known phenomenon that warm air tends to rise.

This results in a difference in pressure between higher and lower levels, with higher levels experiencing positive pressure and lower levels experiencing negative pressure.

The movement of air in and out of the plumbing system may cause a disturbance in the air pressure balance, which can lead to the movement of water in the toilet bowl. 

Toilet Design and Water Traps

toilet design and water traps

So many times, the design of the toilet and its components may have an impact on the flow of water during periods of high wind.

To ensure proper sanitation and hygiene, toilets are fitted with water traps, commonly referred to as P-traps or S-traps.

They effectively prevent the escape of unpleasant odors and the reverse flow of gases. 

The curved sections of the toilet’s plumbing system are designed to retain a small amount of water, creating a seal to prevent the passage of gases from the sewer system.

It is possible that when there are strong winds, they may have an impact on the air pressure within the plumbing system.

And this could potentially cause some movement or slight ripples in the water level of the toilet bowl.

Fact: Wind and air pressure differentials can increase or decrease water circulation in the toilet bowl, depending on the building's height, direction, and surrounding structures. 

Strategies to Prevent Toilet Water Movement When the Wind Blows

preventing toilet water movement in the wind

For some people, it can be bothersome to feel the movement of toilet water when there is a gust of wind.

Thankfully, there are various approaches and actions that can be implemented to reduce or avoid such water displacement

Ventilation System Adjustment

It is important to prioritize proper ventilation within the plumbing system in order to maintain consistent air pressure and reduce the impact of water movement caused by wind.

ventilation system adjustment

By examining and fine-tuning the plumbing vents, it is possible to enhance the equilibrium of air pressure, which can minimize variations that cause water disruptions.

It may be beneficial to seek the advice of a professional plumber to assess the ventilation system and recommend any necessary modifications.

Fact: Contrary to popular belief, a plumbing problem or failure may not always be the cause of water movement in the toilet bowl. 

Water Traps and Drainage

water traps and drainage

The installation and design of water traps in plumbing systems are crucial in preventing gas backflow and reducing water movement.

To maintain a seal that reduces the effect of wind-induced air pressure changes on the toilet water, it is important to check that the traps are unobstructed and in good condition.

Performing routine maintenance and cleaning on drains can aid in the efficient operation of the plumbing system and decrease the chances of water flow issues. 

Seal Gaps and Cracks

seal gaps and cracks

Air infiltration through gaps and cracks in the building envelope is a major cause of wind-induced water movement in toilets.

It is crucial to perform a comprehensive examination of both the interior and exterior of the building, with special attention given to windows, doors, vents, and plumbing penetrations.

To minimize air infiltration, stabilize air pressure, and reduce water disturbances, it is recommended to seal any gaps and cracks that you find.

You can do it in many ways, but using appropriate caulking or weather stripping materials will work better. 

Window and Door Ventilation

window and door ventilation

Maintaining a balanced air pressure and minimizing the impact of wind on toilet water can be achieved by ensuring that windows and doors are properly ventilated.

Regulating airflow can be done effectively by integrating adjustable vents or trickle vents.

The ventilation characteristics aid in preserving pressure balance, avoiding any superfluous water displacement that could arise from alterations in air pressure.

These setups guarantee a smooth and effective atmosphere, while also facilitating uninterrupted airflow without interfering with the operation of restrooms.

Fact: There is a wide difference in the speed and power of water circulation in a toilet bowl due to elements including the toilet's size, shape, water volume, and plumbing system.


Why does toilet water move when the wind blows? Fluctuations in air pressure are responsible for the movement of toilet water caused by wind.

As soon as air currents hit the outer surface of a structure, they generate zones of varying pressure levels.

The variations in pressure impact the air within the structure, which includes the air present in the restroom.

Thankfully, it is possible to take steps to lower the impact of wind on toilet water and ensure a stable atmosphere.