Many people might not realize the dramatic effect sprawl development has on the water quality of a region. However, with sprawl comes pavement, and this pavement decreases the land's natural ability to absorb and filter rainwater before it returns to the water table. In areas that are developed and paved over with malls, parking lots, and highways, rainwater can not be absorbed into the ground and filtered, and it instead enters our lakes and streams in the form of "runoff," which is a mix of rainwater and the many pollutants the water has picked up from our roadways and parking lots (gasoline, chemicals, oil, etc.). When natural buffers are destroyed our water is much more vulnerable, which, in turn, puts all other components of the natural environment, including humans, more at risk.

Open spaces also improve the capacity of the land to absorb and filter rainwater. Christie Whitman, former Administrator of the U.S. Environmental Protection Agency explains, "Some watershed land simply must not be developed. Its natural value in buffering, storing, filtering and recharging far exceeds whatever commercial value it may hold."