The US Environmental Protection Agency (EPA) has published water quality criteria for turbidity. These criteria are scientific assessments of the effects of turbidity, which are used by states to develop water quality standards for water bodies. (States may also publish their own criteria.) Some states have promulgated water quality standards for turbidity, including:
* Louisiana. 25, 50 or 150 NTU, or background plus 10 percent, depending on the water body.
* Vermont. 10 NTU or 25 NTU, depending on water body classification.
* Washington. 5 NTU over background (when background is 50 NTU or less), or 10 percent increase when background is over 50 NTU.