With excessive heat spreading across the country, people are seeking relief by retreating indoors, turning up the AC, and staying well hydrated. In many parts of the country, particularly the Southeast and Southwest, the heat is exacerbated by ongoing drought, which means water is on everyone's mind and is being used at increased rates.

It's common during extended periods of hot and dry weather, like we're experiencing now, for water use to increase, emailed Nancy Barber, Hydrologist with USGS Georgia Water Science Center.

Most noticeable, explained Barber, is the increased demand for electricity for air conditioning, which means more water use at thermoelectric power plants – an amount that's already high. According to the USGS, 53 percent of fresh surface water extracted for human use (in 2005) was used to produce electricity.

Irrigation is also greatly affected by the heat. As temperatures increase, so too does evapotranspiration, and in turn, agriculture's thirst. On a smaller scale, household use also increases due to more people spraying their gardens, jumping in the shower for another rinse, and the occasional topper to the backyard pool.

On a personal level, the best thing to do besides staying hydrated and taking it easy, is to be aware of one's water use and conserve it where possible. Take shorter showers, stuff your dishwasher and clothes washer full before starting the load and, if necessary, only water the yard at an effective time (1pm, or solar noon, is not that time).