Ever hear the story about people across America flushing their toilets simultaneously during the Super Bowl halftime break, destroying the nation’s sewerage systems? 

It’s a great story! But turns out the Super Flush is actually a bit of a… Super Myth.

The source? Back in 1984, a water main break occurred in Salt Lake City on – you guessed it – Superbowl Sunday. Rumour spread that it was due to this synchronised toilet flushing, but the reality was, it was such an old sewerage infrastructure; water main breaks were occurring regularly on days either side of the big event too.

It did however get us thinking – what would happen if everyone on the planet flushed the toilet at the same time? Would the plumbing explode? Would sewerage flood the streets? 

Now let’s not try this at home, folks (or if you do, make sure you’ve got the support of a plumber specialised in repairing damaged and blocked drains at the ready!) – but we decided to investigate based on info from qualified people in-the-know. 

The Flushing Process

Firstly, what exactly happens when we flush the toilet? 

The button or lever you press activates a valve that releases water from the tank into the bowl. This sudden rush of water propels waste and water through the drainpipe, carrying it into the sewer system. 

It initially enters a system of pipes directly under your street, and from here it continues into much larger pipes that journey all the way to your local wastewater treatment facility, undergoing a series of conveyance and treatment processes along the way.

Now, these pipes are sizable, but are they really equipped to handle everyone flushing at once? 

According to a civil engineer at the Utah Water Research Laboratory called Michael Johnson, the effects would not be entirely disastrous but more localised. In some cities, the biggest issue would be the inability for toilets to refill for a while following the communal flush. However, in time, their robust water supply systems will catch up and return to normal.

In other areas with older or less developed sewerage systems, this mass exit of water may result in a far more severe plumbing concern. When a supply line dries out and air is introduced, there is the possibility that the compressed air and pressure build-up could cause a pipe explosion.

Even without a pipe burst – with this much flushing going on there’s also the risk the pipes could get completely overwhelmed with excess wastewater and push it upwards. And you know what that means? It could be heading straight back up to where it came from, potentially oozing out your toilets, sinks, drains, and even out into the streets. Yuk! 

However, there’s also the question of whether everyone’s water ends up in the sewerage system at the exact same time. After all, our toilets are all located at slightly different distances away from the sewer connections. Not to mention differences in water pressure and the like. The system may be able to cope with the situation better than we think.

Systems are in Place

And fortunately, most city water supply operators are pretty prepared for something like this. They continuously monitor and track patterns and the demand for water, and can even send extra gallons down into the distribution system to assist as needed.

So, in short … It’s all a bit of an unknown what would happen. While its certainly got us curious, with around 5 billion people in the world living with proper sanitation (a.k.a toilets as we’re privileged enough to know them today) we’re not sure we want to risk it with an experiment … How about you?