The Secondary Drinking Water Standards or secondary maximum contaminant levels (SMCL) were established as guidelines by the EPA, and they may be enforced by your respective state. The secondary standards were set because of potential aesthetic problems and are divided into three subclasses: Aesthetic, Cosmetic, or Technical Effects.
Aesthetic Effects - undesirable tastes or odors
Cosmetic Effects - effects which do not damage the body but are undesirable, such as skin discoloration (from silver) and tooth mottling (from fluoride), effects on other things such as dingy laundry andstains/coatings on plumbing fixtures, and effects on the water itself such as cloudy or colored water.
Technical Effects - can damage or reduce the efficiency of water treatment equipment, household appliances, boilers, heat exchange units, or on-demand water heaters.
Exceeding a secondary standard does not mean that there is a health-based concern, but that there is a potential aesthetic or nuisance issue although there could be a health-based concern if the contaminant level is significantly higher than the SMCL. Secondary issues related to the water quality are taste, odor, appearance, or impacts or influence on the use of the water. In some cases, a number of these secondary contaminants have EPA Health Advisory Levels when the contaminant is present at levels significantly higher than the Secondary Drinking Water Standard.
Inorganic contaminants can include a combination of metals, salts, compounds, particles, and mineral complexes and, depending on the inorganic, can be regulated under Primary or Secondary Drinking Water Standards. In addition, there are a number of unregulated contaminants that may be a concern and these contaminants can be found in the No Standard section of this website. The common inorganic contaminants regulated under secondary standards include Aluminum, Chloride, Iron, Manganese, Silver, Sulfate / Hydrogen Sulfide / Sulfate-Reducing Bacteria /Sulfur, Total Dissolved Solids, and Zinc.
A condition is a combination of parameters (such as hardness), rather than a single contaminant or parameter, that can have a negative Aesthetic, Cosmetic, or Technical effect on your water quality. It also includes events that are not contaminants themselves but which will affect the water quality (like a broken pipe). Common conditions that can be measured in a water test include: Corrosivity, Foaming Agents, pH, and Color, Taste & Odor (Smell).