Turbidity
microbial contaminant
Soil runoff; disturbance of sediment; inadequate filtration.
EPA regulatory status
Legal limit (MCL)
No numeric MCL
Goal (MCLG)
Not set
Treatment technique, not an MCL. Under the Surface Water Treatment Rules, conventional/direct filtration must achieve turbidity of 0.3 NTU or less in at least 95% of monthly samples and never exceed 1 NTU. There is no MCLG.
Health effects
Turbidity is a measure of water cloudiness. It is not a health concern in itself, but high turbidity can shield microorganisms from disinfection and indicates that filtration may not be working effectively.
This is general public-health information, not medical advice — consult your physician with any health concerns.
National violations
676
EPA's enforcement data (SDWIS/ECHO) records 676 violations of Turbidity's rule nationally.
How to remove Turbidity
Frequently asked questions
What is Turbidity?
Turbidity is a microbial contaminant regulated in US drinking water. Soil runoff; disturbance of sediment; inadequate filtration.
What is the legal limit for Turbidity in drinking water?
Treatment technique, not an MCL. Under the Surface Water Treatment Rules, conventional/direct filtration must achieve turbidity of 0.3 NTU or less in at least 95% of monthly samples and never exceed 1 NTU. There is no MCLG.
What health effects does Turbidity have?
Turbidity is a measure of water cloudiness. It is not a health concern in itself, but high turbidity can shield microorganisms from disinfection and indicates that filtration may not be working effectively.
How many violations of Turbidity limits are on record nationally?
EPA's enforcement data (SDWIS/ECHO) records 676 violations of Turbidity's rule nationally.
How do I remove Turbidity from my water?
Filter technologies certified to reduce Turbidity include: reverse osmosis (NSF/ANSI 58). Look for a filter independently certified against the specific NSF/ANSI standard for this contaminant — general "reduces contaminants" marketing claims are not the same as a contaminant-specific certification.
Source: EPA National Primary Drinking Water Regulations · Data as of 2026-07-16