FEMA National Flood Insurance Program:  

"Flood risk can, and does, change over time. Flood risks change for many reasons: new development, changes in levee classification, and environmental changes, to name a few. As a result FEMA is updating flood hazard maps across the country. These new flood maps, also, known as Digital Flood Insurance Rate Maps (DFIRMs), show flood risk at a property-by-property level.

Underground injection wells, where water and/or other substances are injected into the Earth, are used for a wide variety of purposes. The U.S. Environmental Protection Agency (EPA) regulates around 850,000 underground injection wells through its Underground Injection Control program under the Safe Drinking Water Act. The EPA defines six classes of wells based on their use^[1]:

The Environmental Protection Agency (EPA) provides a range of resources which address the health effects of contaminants in drinking water. Their Drinking Water Contaminants page provides a useful background on the sources and effects of drinking water contaminants for the following contaminant types: