where does water in modern plumbing come from and where does it go?

Question

I don’t understand how you can just leave the tap on–where does that water come from?

Is the water from your kitchen sink and your toilet the same water?

Is water really being “wasted”?

In: Engineering

Answer 1

Most water comes from either surface bodies of water (lakes, rivers) or from wells. Washington DC’s water comes from the [Potomac River](https://en.wikipedia.org/wiki/Washington_Aqueduct). New York City’s water comes from [large lakes in upstate New York](https://en.wikipedia.org/wiki/New_York_City_water_supply_system) and transported over miles of pipes down to the city. Other locations pump water from underground aquifers — places where water gets kind of ‘stuck’ underground in the soil due to the different layers of soil.

In municipal systems the water will be cleaned and filtered via various means, including chlorination and fluoridation. Failure to properly filter and clean the water can results in [people getting sick.](https://en.wikipedia.org/wiki/1993_Milwaukee_cryptosporidiosis_outbreak)

It will then be pumped into a network of water mains to pressurize the system. Various intermediate pumps may exist to keep the system pressurized with sufficient water to meet household demand.

Yes, the same water coming from your sink tap is also the water that goes into your toilet. Its also the same water that comes out of your shower head and garden hose.

The water once it goes down the drain will go to a sewage treatment plant. It will be treated to remove the worst-of-the-worst and allowed to return to the Earth.

Some places will discharge it to recharge basins where it can percolate down back to the aquifer, others will pump it several miles out in to the ocean or some other body of water.

If you’re not on a municipal sewer system, it will go to a septic system which allows water to percolate back into the Earth while separating out “sludge” and letting various bacteria eat and decompose the biological material.

The water down the drain is wasted in some sense, but not others.

The water eventually returns to the Earth.

However, our supplies of clean accessible water are dwindling. It also takes a lot of effort/energy to convert water from “raw” to safe and ready to drink.

Locations like the Colorado River, which is used to supply water to 5+ states, are at historic lows.