THE LAW
One law sets the limits on your tap water.
The Safe Drinking Water Act, passed in 1974, lets EPA set national standards for public water systems.
THE TWO NUMBERS
Goal and limit.
For each regulated contaminant, EPA sets a health goal (MCLG) and an enforceable limit (MCL). For contaminants EPA considers likely to cause cancer, the health goal is generally set at zero. The legal limit is set as close to the goal as treatment and cost allow.
COVERED
Who has to follow it.
- Public water systems: cities, towns and other systems serving the public
- More than 90 contaminants have national limits
NOT COVERED
Who doesn’t.
- Private wells, which owners test and treat themselves
- Bottled water, which the FDA regulates instead
SOURCES
Where these facts come from.
QUESTIONS
Straight answers.
Why is the goal zero for some contaminants?
For contaminants likely to cause cancer, EPA generally sets the health goal at zero.