Open space, such as farmland, helps protect the quality of our drinking water by allowing rainwater to soak slowly into the soil, naturally filtering out pollutants. Water does not drain through concrete or asphalt, however, and in highly developed areas contaminants quickly make their way into nearby rivers and streams and combined-sewer systems. Heavy rain storms can cause these systems to overflow, tainting drinking-water sources such as Lake Michigan and posing serious health risks to both humans and nature. Unmanaged rainwater runoff, or stormwater, can also flood homes and businesses. 

Additionally, farmland’s natural percolation process recharges the groundwater, a major source of drinking water. But as the region grows, water supplies become increasingly taxed—development in McHenry County, for example, is outpacing the ability of its groundwater aquifers to recharge.