Mandatory buffer zones are a way to protect water quality. Effective August 2000, 30-foot buffers must be established on all navigable waterways in twenty coastal counties. Most development is also banned in the buffer zone. Buffer zones filter nutrients, bacteria, and other pollutants from stormwater runoff, thereby reducing the pollutant flow into waterways. The Coastal Resources Commission adopted the buffer zone rule after two years of discussion on ways to protect water quality.