From stream to sink
Did you know that the average American family of four uses about 400 gallons of water per day in and around their home? This added up to about 27.4 billion gallons of water per day being drawn for households across the United States in 2010 to be used for drinking, washing clothes, watering the lawn, flushing toilets, cooking food, showering, and more. The majority of this water that flows through the pipes in our homes comes from the public supply (remember this term from lesson one?), about 63% of which is drawn from surface water sources, and the remaining 37% is pumped from underground sources such as aquifers. Not one of the homes on the public supply? If your family draws their own water, it's very likely from a well, which pumps up groundwater to meet your needs.
What goes up must come down, and water that is pumped into your home is very likely going to be drained away from it as well, whether that's to a backyard septic tank or a large-scale wastewater treatment facility. Either way, the water needs to be treated, or cleaned, after it's used by people and before it can be returned to the watershed. While lesson one covered many ways in which the ecosystems of the watershed work to maintain good water quality, these systems are delicate, and would be overwhelmed with the amount of pollution they would receive if steps were not first taken to treat the used water, also called wastewater. When communities' wastewater is sent through a wastewater treatment facility, it goes through several steps of filtration and purification, where the facility can remove large pieces of debris, kill disease-causing bacteria, reduce the levels of nutrients such as nitrogen and phosphorous in the water, and more, improving the quality of the water that is released back into the watershed. (If you want to learn more about how wastewater treatment facilities work, check out this virtual visit to a wastewater treatment plant from the US Geological Survey. If you're interested in how water is made safe to drink before it arrives to your home, take a look at this explainer from the same agency.)
In this manner, each one of us touches a significant portion of this lifeblood of the watershed, as billions of gallons of water move from rivers, reservoirs, and aquifers, into our homes, and then eventually back out to the watershed each day. As the mighty waters of the watershed take a pit stop in our sinks, bathtubs, hoses, and toilets, small actions we take at home with this water can have a big impact on water quality down the line.