National Secondary Drinking Water

A National Secondary Drinking Water Regulation (NSDWR or secondary standard) is a non-enforceable guideline regarding contaminants that may cause cosmetic effects (such as skin or tooth discoloration) or aesthetic effects (such as taste, odor, or color) in drinking water. EPA recommends secondary standards to water systems but does not require systems to comply. However, states may choose to adopt them as enforceable standards. This information focuses on national primary standards. 

Table 6. Summary of National Secondary Drinking Water Regulations.

EPA ODW National Secondary Drinking Water Regulations—Secondary maximum contaminant levels 0.05 to 0.2 mg/L 40 CFR 143.3 EPA 1979a... 

National Secondary Drinking Water Regulations (1991) Final Rule. Fed Reg 56 20 3526... 

National Secondary Drinking Water Regulations (secondary standard) are nonenforceable criteria/ guidelines. They are set at levels that protect against aesthetic effects (e.g., taste, odor, or color) and/or cosmetic effects (e.g., teeth and skin discoloration). Secondary standards are not enforceable under the federal SDWA, however, states can adopt them as enforceable standards. 

Table 8.9 National Secondary Drinking Water Regulations (NSDWRs) for Potable Water in the United States...

EPA. 1979a. National secondary drinking water regulations. U.S. Environmental Protection Agency. Federal Register 44 42198 40 CFR 143. 

EPA also sets National Secondary Drinking Water Regulations for contaminants that affect the aesthetic (e.g., taste, color or odor), cosmetic (e.g., skin or tooth discoloration) or technical (e.g., corrosivity or scaling) qualities of drinking water. These non-enforceable guidelines include secondary MCLs and recommendations for monitoring (EPA, 2004b). 

USEPA (1998). National Secondary Drinking Water Regulations. Code of Federal Regulations, 40, Sections 143.1-143.5. 

Secondary maximum contaminant levels given in 40 CFR Part 143 (July 1987) "National Secondary Drinking Water Regulations."... 

National Primary Drinking Water Standards and National Secondary Drinking Water Standards. Visit the EPA Web site at http //water.epa.gov/lawsregs/rulesregs/sdwa/curren-tregulations.cfm (accessed October 15, 2010). 

NSDWR National secondary drinking water regulations... 

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