question: How does high wind outside make the water move in a toilet bowl?
comment: Your toilet is connected to something called a Soil Vent Pipe (SVP). This is a soil pipe (used to transport waste) with a vent at the top, which allows gas build-ups to escape and stops odour coming back up through your toilet/sink. An example of one can be seen [here]( URL_0 ) The wind pressure outside can push air into the SVP, which your toilet waste is connected too, and that increase in pressure forces your toilet water to move up. As the pressure drops, the water moves down, and a little bit goes over the U-bend and down the pipe into the sewer. So, over time, your water will drop.
passages: It is a commonly held misconception that when flushed, the water in a toilet bowl swirls one way if the toilet is north of the equator and the other way if south of the equator, due to the Coriolis effect – usually, counter clockwise in the northern hemisphere, and clockwise in the southern hemisphere. In reality, the direction that the water takes is much more determined by the direction that the bowl's rim jets are pointed, and it can be made to flush in either direction in either hemisphere by simply redirecting the rim jets during manufacture. On the scale of bathtubs and toilets, the Coriolis effect is too weak to be observed except under carefully controlled laboratory conditions.
   Contrary to popular misconception, bathtubs, toilets and other residential water receptacles do not drain in opposite directions in the Northern and Southern Hemispheres because the magnitude of the Coriolis force is negligible at this scale. Forces determined by the initial conditions of the water (e.g. the geometry of the drain, the geometry of the receptacle, pre-existing momentum of water, etc.) are likely to be orders of magnitude greater than the Coriolis force and hence will determine the direction of water rotation, if any. For example, identical toilets flushed in each hemisphere will drain in the same direction, and this direction will be determined mostly by the shape of the toilet bowl.
   All plumbing fixtures have traps in their drains; these traps are either internal or external to the fixtures. Traps are pipes which curve down then back up; they 'trap' a small amount of water to create a water seal between the ambient air space and the inside of the drain system. This prevents sewer gas from entering buildings. 
  
  Most water closets, bidets, and many urinals have the trap integral with the fixture itself. The visible water surface in a toilet is the top of the trap's water seal.
   The plot of the episode is based on the story of Michael Fay, an American teenager who was caned in Singapore in 1994 for vandalizing cars. This episode perpetuated a popular myth that the Coriolis effect affects the motion of drains in the Northern and Southern Hemispheres. In reality, the Coriolis effect affects global weather patterns. The amount of water in a toilet or sink is much too small to be affected by it.
   At the top of the toilet bowl is a rim with many angled drain holes that are fed from the tank, which fill, rinse, and induce swirling in the bowl when it is flushed. Some designs use a large hole in the front of the rim to allow faster filling of the bowl. There may also be a siphon jet hole about one inch (2.5 cm) diameter in the bottom of the toilet.
   Section::::Bowl design.:Non-siphonic bowls.:Washdown toilet.
  
  Washdown toilets are the most common form of pedestal and cantilever toilets outside North America. The bowl has a large opening at the top which tapers down to a water trap at the base. It is flushed from the top by water discharged through a flushing rim or jets. The force of the water flowing into the bowl washes the waste through the trap and into the drains.
   The water in the toilet bowl is connected to a pipe shaped like an upside-down U. One side of the U channel is arranged as a siphon tube longer than the water in the bowl is high. The siphon tube connects to the drain. The bottom of the drain pipe limits the height of the water in the bowl before it flows down the drain. The water in the bowl acts as a barrier to sewer gas entering the building. Sewer gas escapes through a vent pipe attached to the sewer line.
   An island fixture vent provides an elegant solution for this necessity: when the drain is opened, water displaces the sewer gas up to the sanitary tee, the water flows downward while sewer gas is displaced upward and toward the vent. The vent can also provide air to fill any vacuum created.
  
  The key to a functional island fixture vent is that the top elbow must be at least as high as the "flood level" (the peak possible drain water level in the sink). This ensures that the vent never becomes waterlogged.
  
  Section::::Island fixture vent.:Cost.
   The rapid influx of water into the bowl causes the standing water in the bowl to rise and fill the S-shaped siphon tube mounted in the back of the toilet. This starts the toilet's siphonic action. The siphon action quickly "pulls" nearly all of the water and waste in the bowl and the on-rushing tank water down the drain in about 4–7 seconds —it flushes. When most of the water has drained out of the bowl, the continuous column of water through the siphon is broken when air enters the siphon tube. The toilet then gives its characteristic gurgle as the siphonic action ceases and no more water flows out of the toilet.
   Standing water in the bowl acts as a barrier to sewer gas coming out of the sewer through the drain, and also as a receptacle for waste. Sewer gas is vented through a separate vent pipe attached to the sewer line. The water in the toilet bowl is connected to the drain by a drain pipe shaped like an extended "S" which curves up behind the bowl and down to the drain. The portion of the channel behind the bowl is arranged as a siphon tube, whose length is greater than the depth of the water in the bowl. The top of the curving tube limits the height of the water in the bowl before it flows down the drain. The waterways in these toilets are designed with slightly smaller diameters than a non-siphonic toilet, so that the waterway will naturally fill up with water each time it is flushed, creating the siphon action.
   The double trap siphonic toilet is a less common type that is exceptionally quiet when flushed. There is a device known as an aspirator which uses the flow of water on a flush to suck air from the cavity between the two traps, reducing the air pressure there to create the siphon which sucks water and waste from the toilet bowl. Towards the end of the flush the aspirator ceases being covered in water, thus allowing air into the cavity between traps to break the siphon without the noise while the final flush water fills the pan.
  
  Section::::Bowl design.:Non-siphonic bowls.
   A "true siphonic toilet" can be easily identified by the noise it makes. If it can be heard to suck air down the drain at the end of a flush, then it is a true siphonic toilet. If not, then it is either a double trap siphonic or a non-siphonic toilet.
  
  If water is poured slowly into the bowl it simply flows over the rim of the waterway and pours slowly down the drain—thus the toilet does not flush properly.
   When a fixture trap is venting properly, a "sucking" sound can often be heard as the fixture vigorously empties out during normal operation. This phenomenon is harmless, and is different from "trap suckout" induced by pressure variations caused by wastewater movement "elsewhere" in the system, which is not supposed to allow interactions from one fixture to another. Toilets are a special case, since they are usually designed to self-siphon to ensure complete evacuation of their contents; they are then automatically refilled by a special valve mechanism.
  
  Section::::Internal venting.
   Section::::Accident.
   Section::::Design and location.
  
  Section::::Design and location.:Product.
   The distribution of hydraulic head through an aquifer determines where groundwater will flow. In a hydrostatic example (first figure), where the hydraulic head is constant, there is no flow. However, if there is a difference in hydraulic head from the top to bottom due to draining from the bottom (second figure), the water will flow downward, due to the difference in head, also called the "hydraulic gradient".
  
  Section::::Hydraulic head in groundwater.:Atmospheric pressure.
   Section::::Bowl design.
  
  The "bowl" or "pan" of a toilet is the receptacle that receives bodily waste. A toilet bowl is most often made of a ceramic, but can sometimes be made of stainless steel or composite plastics. Toilet bowls are mounted in any one of three basic manners: above-floor mounted (pedestal), wall mounted (cantilever), or in-floor mounted (squat toilet).
   A blocked vent is a relatively common problem caused by anything from leaves, to dead animals, to ice dams in very cold weather, or a horizontal section of the venting system, sloped the wrong way and filled with water from rain or condensation. Symptoms range from bubbles in the toilet bowl when it is flushed, to slow drainage, and all the way to siphoned (empty) traps which allow sewer gases to enter the building.
   Typically, elaborate, capital-intensive storm sewer networks are engineered to deal with stormwater. In some cities, such as the Victorian era London sewers or much of the old City of Toronto, the storm water system is combined with the sanitary sewer system. In the event of heavy precipitation, the load on the sewage treatment plant at the end of the pipe becomes too great to handle and raw sewage is dumped into holding tanks, and sometimes into surface water.
  
  Autonomous buildings can address precipitation in a number of ways:
   Section::::Design and location.:Location.
   Section::::Design and location.:Moderator.
   After flushing, the flapper valve in the water tank closes or the flush valve shuts; water lines and valves connected to the water supply refill the toilet tank and bowl. Then the toilet is again ready for use.
  
  Section::::Bowl design.:Siphonic bowls.:Double trap siphonic toilet.
   BULLET::::- Blow-out — Water droplets blown out of the cooling tower by wind, generally at the air inlet openings. Water may also be lost, in the absence of wind, through splashing or misting. Devices such as wind screens, louvers, splash deflectors and water diverters are used to limit these losses.
   Section::::Applied to the Earth.:Draining in bathtubs and toilets.
   Within the bowl, there are three main waterway design systems: the siphoning trapped system (found primarily in North American residential installations, and in North American light commercial installations), the non-siphoning trapped system (found in most other installations), and the valve-closet system (found in trains, passenger aircraft, buses, and other such installations around the world). Older style toilets called "washout" toilets are now only found in a few locations.
  
  Section::::Bowl design.:Siphonic bowls.
  
  Section::::Bowl design.:Siphonic bowls.:Single trap siphonic toilet.
  