Chlorine
EPA Designation Regulated
EPA Classification Disinfectants
EPA Levels 1,2 MRDLG=41 MCLG (mg/L)
MRDL=4.01 MCLG (mg/L)
Alternative Names none
Sources Water additive used to control microbes
Water additive used to control microbes

Overview

The gaseous or liquid form of chlorine (CL2) is a water additive used by municipal water systems to control microbes. It is relatively inexpensive and has the lowest production and operating costs and longest history for large continuous disinfection operations. Chlorine is a powerful oxidant.

Uses

Used as a water additive in many municipal water systems to control microbes.

Health Effects

Some people who use water containing chlorine in excess of the maximum residual disinfectant level could experience irritating effects to their eyes, nose and skin. Some people who drink water containing chlorine well in excess of the maximum residual disinfectant level could experience stomach discomfort.

EPA Data Source: Chlorine

EPA Definitions:

1Maximum Contaminant Level Goal (MCLG) - The level of a contaminant in drinking water below which there is no known or expected risk to health. MCLGs allow for a margin of safety and are non-enforceable public health goals.

Maximum Contaminant Level (MCL) - The highest level of a contaminant that is allowed in drinking water. MCLs are set as close to MCLGs as feasible using the best available treatment technology and taking cost into consideration. MCLs are enforceable standards.

Maximum Residual Disinfectant Level Goal (MRDLG) - The level of a drinking water disinfectant below which there is no known or expected risk to health. MRDLGs do not reflect the benefits of the use of disinfectants to control microbial contaminants.

(TT) Treatment Technique - A required process intended to reduce the level of a contaminant in drinking water.

Maximum Residual Disinfectant Level (MRDL) - The highest level of a disinfectant allowed in drinking water. There is convincing evidence that addition of a disinfectant is necessary for control of microbial contaminants.

2 Units are in milligrams per liter (mg/L) unless otherwise noted. Milligrams per liter are equivalent to parts per million.