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Collected Wisdom's Philip Jackman (Louie Palu/The Globe and Mail)
Collected Wisdom's Philip Jackman (Louie Palu/The Globe and Mail)

collected wisdom

Help! The water in my toilet is moving Add to ...

Hello. Drain-You-Dry Plumbing Services here. What? You need a small adjustment to your bathroom sink? No problem. That will be $500.


Why does the water in the toilet move on very windy days? Graham Duncan of Mahone Bay, N.S., wants to know.


“It's due to the little black pipe that sticks out of every building's roof, commonly called the stink pipe,” writes Peter A. Lewis-Watts of Barrie, Ont. That pipe, properly called a vent stack, is critical to the proper functioning of all drains, be they on sinks, tubs, showers or toilets.

Each time a toilet is flushed (or a plug is pulled out), water enters the drainage system, displacing air. The air must escape through the vent stack, he says, otherwise it could bubble back through the water draining from the toilet (or bathtub/sink), allowing sewer gases, which are always present in drainage pipes, to enter the residence.

At the same time, water flows down the drainage pipes freely because air entering through the vent stack prevents a vacuum from forming, he says. “Without the vent stack, the vacuum would suck the water out of the water traps (the standing water in the toilet and in the curved pipe under every sink forms a water trap), again allowing sewer gases to enter the dwelling.”

As wind gusts over the top of the vent stack, he says, the air pressure in the drain system rises and falls, attempting alternately to push and suck the water out of the water traps. (It might succeed in a hurricane or tornado). “That's why the water in the toilet (and in all other drain traps) moves on windy days.”


Why do we have to have manholes in the road? asks T.J. Machado of Mississauga. They crater and make for bad driving conditions. Why can't we have them on the sidewalk instead?


Manholes provide access to underground structures such as sewers and tunnels for cables, writes Brij Seoni of Waterloo, Ont. Therefore, a manhole is normally placed directly above the structure it serves. Underground tunnels and sewers don't normally follow the path of sidewalks, he says, so we sometimes have manholes in the middle of the road.


In response to our item last week about why there are jogs in the Saskatchewan-Manitoba boundary, Charles Grierson of Surrey, B.C., offers this reminiscence.

“Nearly 60 years ago, as a university student, I worked one summer for Hudson Bay Mining and Smelting in Flin Flon, Man. I spent a month in the copper smelter, which consisted of a large furnace that just happened to lie across the border line.

“The front of the furnace, where most of the action occurred, was in Saskatchewan and the back was in Manitoba. It was generally known that if you had an accident at the back of the furnace, you crawled around to the front to be found, because the Saskatchewan Workers' Compensation Board paid 75 per cent compensation while the Manitoba WCB paid only 66 per cent.”


  • Jackie Phillips of Toronto asks: Why don't woodpeckers bash their brains out?
  • “Is there any evidence that animals can appreciate music?” asks Micki Honkanen of Toronto. “It seems to me that a drumbeat would resonate with any animal with a heartbeat.”
  • Based on the top 100 earners, what is the most lucrative professional sport? Geoff Houghton of Sudbury wants to know.

Let's hear from you: If you have the answer to one of these questions (or a question of your own) send an e-mail to wisdom@globeandmail.com. Please include your location and a daytime phone number.

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