Where does your water come from?

As more and more people move to urban areas, our reliance on public water suppliers has increased. In the United States 86% of people get their water from a municipal supply, while a shrinking minority use private wells. Check your water bill for the name of your water supplier, or search online using the EPA Watershed database or this interactive site from Pur water filters.

There are 155,000 water supply companies in the U.S. and most people don’t have a choice about where their water comes from. Find your suppliers website and look for an annual report; the government requires them to test and release this information every July. This is the fastest way to find out what’s in your water.

When you open your faucet, you’re drinking water that originated from one of these natural sources.

Mountain snowmelt can accumulate in reservoirs; lakes and rivers can provide water for communities; or, for about a third of the U.S. their water comes from groundwater (which flows between gravel and sediment layers, and is not, in fact, a big underground lake).

Click the arrows to follow the path of municipal water.

Water treatment facilities are designed to make your water safe to drink. Water passes through screens to filter out large material like sticks, organisms, or that soda bottle you threw out last weekend.

As the water is pumped towards it’s destination, it is kept open to the air to allow gaseous contaminants to escape.

Further material is removed by coagulation—adding electrically charged chemicals that attract participles suspended in the water. Then, during flocculation, the water is gently stirred so that the clumps (flocs) accumulate and grow large enough to sink to the bottom of the water.

The water passes through several layers of filters to remove even the smallest particles.

Once the water is as clean as it’s going to get, treatment plants actually add some additional chemicals. Chlorine gas is injected to kill any harmful bacteria, and fluoride is added for dental health benefits. Chemicals can also be added to remove natural minerals like calcium to make the water “softer.”

Treated water is then stored under pressure so that it will readily flow into your pipes. Electric pumps can squeeze a reservoir of water to keep it pressurized, or water can be pumped into water towers to let gravity to do the work of pushing water to your faucet.

Like any resource, treated water is stockpiled for emergencies.

Water mains take the final product throughout the city, where individual waterlines branch off to their final destinations.