Due to prolonged drought in the Western part of the U.S., Lake Mead has experienced historic lows. Lake Mead provides water to Arizona, California, and Nevada.

EPA works with drinking water utilities to provide clean and safe drinking water. This goal can be challenging under some extreme weather events such as drought.

Climate change is projected to intensify short-term (seasonal or shorter) drought risk across most of the U.S. as well as intensify long-term droughts in large areas of the Southwest, southern Great Plains, and Southeast. Short term and long term drought both threaten the ability of drinking water utilities' efforts to maintain safe and effective service now and into the future.

During drought, water utilities may face a reduced volume of water or loss of water supply sources, while at the same time experiencing increased demand from customers. A drought can reduce short term water sources, such as reservoirs or lakes. Drought can also affect longer-term water storage or supply such as mountain snowpack. An increase in drought risk can necessitate drinking water utilities to reassess and revise long-term plans to ensure access to source water availability.

A reduction in available source water can concentrate contaminate levels in source waters and lead to diminished source water quality. Poor source water quality can affect treatment costs and the ability to meet drinking water standards.

The reduction in available water supply can also lead to the consideration and development of alternative water sources, such as groundwater. In coastal areas, increased groundwater withdrawals may exacerbate other climate impacts such as saltwater intrusion.

In some areas, drought and associated periods of high temperatures will contribute to dry conditions that drive wildfires. Wildfires can threaten water facilities, increase erosion and adversely affect source water quality. Wildfires also pose significant public health affects by diminishing air quality.