This color-coded map shows the estimated median sound levels for areas of the 48 contiguous states of the U.S. The range goes from deep blue (low decibels) to brown (high decibels). The estimates were derived using a computer model that accounts for the factors influencing natural sounds (wind, vegetation, water flow) as well as human-caused noise. The highest level on the color scale is 64 decibels, roughly equivalent to the sound of a clothes washer heard a distance of 3 feet (1 meter).