Drinking Water Regulations

   
EPA Drinking Water Secondary Contaminant List

Table of Secondary Standards

Contaminant

Secondary MCL

Noticeable Effects above the Secondary MCL
Aluminum 0.05 to 0.2 mg/L* colored water
Chloride 250 mg/L salty taste
Color 15 color units visible tint
Copper 1.0 mg/L metallic taste; blue-green staining
Corrosivity Non-corrosive metallic taste; corroded pipes/ fixtures staining
Fluoride 2.0 mg/L tooth discoloration
Foaming agents 0.5 mg/L frothy, cloudy; bitter taste; odor
Iron 0.3 mg/L rusty color; sediment; metallic taste; reddish or orange staining
Manganese 0.05 mg/L black to brown color; black staining; bitter metallic taste
Odor 3 TON (threshold odor number) "rotten-egg", musty or chemical smell
pH 6.5 - 8.5 low pH: bitter metallic taste; corrosion
high pH: slippery feel; soda taste; deposits
Silver 0.1 mg/L skin discoloration; graying of the white part of the eye
Sulfate 250 mg/L salty taste
Total Dissolved Solids (TDS) 500 mg/L hardness; deposits; colored water; staining; salty taste
Zinc 5 mg/L metallic taste

*mg/L is milligrams of substance per liter of water.