toilet flushes and hockey games

In keeping with my attempts at keeping abreast of events in "the old country", I came across an interesting item from The Big Game.

During the gold medal round of the Men's Hockey event at the Olympics, an estimated 80% of the country watched the game. That's 27 million people.

The water utility in Edmonton released a graph of water usage in the city that showed how the high viewership of the game impacted that usage. It's amazing.

I wonder what televised events could cause this to happen in Japan?