Lake Tahoe is losing its crystal water clarity at the alarming rate of more than a foot a year. At the current rate of decline, it is estimated that Lake Tahoe will lose its blue brilliance in just ten years.  Non-point source (NPS) pollution, or pollution originating from many diffuse sources is contributing to the decline in Lake Tahoe's water clarity. NPS pollution is caused when rain or snowmelt causes overland flow that transports various pollutants from the ground's surface directly into the surface waters that lead to Lake Tahoe.

Research has found that the addition of sediment and nutrients such as nitrogen and phosphorus from non-point source pollution to Lake Tahoe promotes algal blooms that result in a further loss of water clarity. The best way to prevent this is to slow and store runoff using BMPs.