Skip to main content
U.S. flag

An official website of the United States government


The color of natural waters is imparted by suspended sediment or dissolved constituents such as tannins or iron. The color of water with low amounts of suspended sediments is assessed using a visual comparison to a colored glass disc, called a color wheel (pictured below). Too much color in natural waters can be detrimental to the ecosystem. The color blocks some light from entering the water and can then inhibit aquatic plant growth. Highly colored water is also undesirable for drinking and other household uses as it can cause stains and impart a bad taste to water.