Fluoride
inorganic chemical
Water additive for dental health; erosion of natural deposits; discharge from fertilizer and aluminum factories.
EPA regulatory status
Legal limit (MCL)
4 mg/L
Goal (MCLG)
4 mg/L
Primary MCL 4.0 mg/L (enforceable). MCLG = 4.0 mg/L. There is also a non-enforceable Secondary standard (SMCL) of 2.0 mg/L set to prevent dental fluorosis (tooth mottling) in children.
Health effects
At levels above the MCL, long-term exposure can cause skeletal fluorosis (bone pain and tenderness). Levels above the 2.0 mg/L secondary standard can cause dental fluorosis (mottled teeth) in children. Fluoride is intentionally added by many systems at ~0.7 mg/L for dental-health benefits.
This is general public-health information, not medical advice — consult your physician with any health concerns.
National violations
47,811
EPA's enforcement data (SDWIS/ECHO) records 47,811 violations of Fluoride's rule nationally.
How to remove Fluoride
distillation
NSF/ANSI 62
Frequently asked questions
What is Fluoride?
Fluoride is a inorganic chemical regulated in US drinking water. Water additive for dental health; erosion of natural deposits; discharge from fertilizer and aluminum factories.
What is the legal limit for Fluoride in drinking water?
Primary MCL 4.0 mg/L (enforceable). MCLG = 4.0 mg/L. There is also a non-enforceable Secondary standard (SMCL) of 2.0 mg/L set to prevent dental fluorosis (tooth mottling) in children.
What health effects does Fluoride have?
At levels above the MCL, long-term exposure can cause skeletal fluorosis (bone pain and tenderness). Levels above the 2.0 mg/L secondary standard can cause dental fluorosis (mottled teeth) in children. Fluoride is intentionally added by many systems at ~0.7 mg/L for dental-health benefits.
How many violations of Fluoride limits are on record nationally?
EPA's enforcement data (SDWIS/ECHO) records 47,811 violations of Fluoride's rule nationally.
How do I remove Fluoride from my water?
Filter technologies certified to reduce Fluoride include: reverse osmosis (NSF/ANSI 58), distillation (NSF/ANSI 62). 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