Under Pressure: How the Hell Does Running Water Work?

Ever taken a moment to consider what the hell goes into being able to turn a handle on a sink pretty much anywhere you’ve ever lived and have clear, clean(ish?) running water?  Me neither.

That’s because it’s a perk I’ve come to associate as a given – it’s not like I was born into a world where running water was this new, cutting edge technology like it was the Internet or the Chipotle burrito.  So let’s just take a second to appreciate this little facet of our daily lives that may be considered the cornerstone of modern civilization.  

THE SOURCE

Where you get your water depends largely upon where you live.  If you live in a city, 99% of the time your water is getting supplied by a water treatment facility.  If you live out in the country, you’re more likely to live on a well, i.e. from a natural, underground source already on or near your property.  Two completely different living situations, two completely different mechanisms:

THE WELL

Since a well is underground, there needs to be a mechanism to get that water out and up into your home.  To do that, an electric pump is used to get the ‘ground’ water out of the well, and up into a pressure tank in your home.  The water that most wells pump comes out of your pipes ‘as is’ – it was originally precipitation that seeped into the ground and was filtered through rocks.  Additional filtration can be used to remove excess minerals and make the water less ‘hard,' but comes up 100% drinkable which, in the day and age of reverse osmosis and Montezuma's revenge, is pretty freaking amazing.  

The pressure tank that the pump fills is airtight, and as water gets pumped in it creates a pressure against the air within the tank... think the reverse of a Super Soaker: water is already in the tank, you pump the AIR in instead of the water, press the trigger and your result is your crying sibling or destroyed anthill. 

As that water supply is used, the pump will kick-in to pump more into the tank to keep the pressure consistent.   One minor flaw: this system relies exclusively on electricity.  When the power goes out, you’ll get as much water as was pumped into your tank and has been pressurized.  After that initial supply runs out, you’re on your own.

THE TOWER

In most cases, ‘public’ water starts out at a water treatment facility that’s been collected from excess runoff in the form of open reservoirs – the water you use on a day-to-day basis probably traveled hundreds if not thousands of miles (maybe drop a quiet 'thanks!' next time you turn on the faucet?).  These reservoirs collect millions upon millions of gallons of water throughout the year and are replenished from other bodies of water and rainwater.  Since they’re so out in the open (see pic below), its contents are funneled into the treatment facility to be filtered for sediment and treated with other chemicals like fluoride and chlorine.  In fact, they’re sometimes too wide open – in 2014 a reservoir in Portland, Oregon flushed over 38 million gallons of water because some idiot thought it would be cool to piss into it (this happens more often than you think, and the punishment is a lot less severe than you’d probably anticipate). 

From the treatment plants, a water pump (one of a various assortment) is used to get the cleaned H20 moving toward you, the customer.  The water gets pumped out to the city and in most cases up into a water tower.  These towers are designed to handle upwards of a day’s worth of water for their designated communities and have a mechanism that refills much like a toilet does – when it reaches a certain level, it opens up to the pump to refill. 

From there, as it turns out, there’s a reason all these massive water towers are up on stilts: what goes up must come down.  For each foot off the ground the water is raised, a percentage of pounds per square inch (PSI) is applied to it.  Considering the sheer amount of water and how high up off the ground it is, the pressure from gravity is immense - enough to push itself out into our homes and out of our sinks.  I mean... that is a lot of damn pressure, right?!  When you turn that handle, you’re activating pressure generated miles and miles away from your city’s pump and water tower just because you were thirsty. 

If your town’s pump fails or you have a massive power outage, that tower contains enough pressure to keep that water flowing into your home.  As long as there’s a pump to get that water up to the tower, you’ll be supplied (hence why the treatment plant pumps normally have backup power in the event of an emergency). 

UP ON THE ROOF...

A small caveat: living in a large apartment building… that pressure can only fight against gravity for so long on its own.  If you live in a tall apartment building, odds are that you have your own water tower on top of your building, as well your own water pump below the building.  The water comes in from the pipes via the method mentioned above, and your building’s pump then forces that water to your roof and into your tower.  Though they’re generally not as big as the towers you see out there in the open, they’re so high up that the pressure is enough to push its way back down into the building all on its own. 

It’s the ultimate ‘if it ain’t broke’ framework - in a world of constantly evolving technological advances, it’s kind of astounding that the mechanisms behind the scenes of the running water are literally thousands of years old (elevated water towers were used as early as 3000 BC).