Understanding the Terms

• Non-Detects (ND) - laboratory analysis indicates that the constituent is not present.
• ND/Low - High - For water systems that have multiple sources of water, the Utah Division of Drinking Water has given water systems the option of listing the test results of the constituents in one table, instead of multiple tables. To accomplish this, the lowest and highest values detected in the multiple sources are recorded in the same space in the report table.
• Parts per million (ppm) or Milligrams per liter (mg/L) - one part per million corresponds to one minute in two years or a single penny in $10,000.
• Parts per billion (ppb) or Micrograms per liter (µg/L) - one part per billion corresponds to one minute in 2,000 years, or a single penny in $10,000,000.
• Parts per trillion (ppt) or Nanograms per liter (ng/L) - one part per trillion corresponds to one minute in 2,000,000 years, or a single penny in $10,000,000,000.
• Parts per quadrillion (ppq) or Picograms per liter (pg/L) - one part per quadrillion corresponds to one minute in 2,000,000,000 years, or one penny in $10,000,000,000,000.
• Picocuries per liter (pCi/L) - a measure of the radioactivity in water.
• Millirems per year (mrem/yr) - measure of radiation absorbed by the body.
• Million fibers per liter (MFL) - measure of asbestos fibers longer than 10 micrometers.
• Nephelometric Turbidity Unit (NTU) - measure of water clarity; turbidity above 5 NTU is just noticeable to the average person.
• Action Level (AL) - the concentration of a contaminant which, if exceeded, triggers treatment or other requirements that a water system must follow.
• Treatment Technique (TT) - a required process intended to reduce the level of a contaminant in drinking water.
• Maximum Contaminant Level (MCL) - the highest level of a contaminant allowed in drinking water. MCLs are set as close to MCLGs as feasible using the best available treatment technology.
• Maximum Contaminant Level Goal (MCLG) - the level of a contaminant in drinking water below which there is no known or expected risk to health; allows for a margin of safety.
• Maximum Residual Disinfectant Level (MRDL) - the highest level of a disinfectant allowed in drinking water. There is convincing evidence that the addition of a disinfectant is necessary for the control of microbial contaminants.
• 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 disinfectants used to control microbial contaminants.
• Date - because of required sampling time frames (e.g., yearly, every 3, 4, or 6 years), sampling dates may appear outdated.
• Waivers (W) - some water systems receive waivers exempting them from sampling certain chemicals when those chemicals are not used or stored near drinking-water sources; waivers tie into Drinking Water Source Protection Plans.

Why Are There Contaminants in My Drinking Water?

Drinking water—whether it comes from a city tap, a household well, or a commercial bottling plant—begins as surface- or ground-water. As it moves over land or seeps through soil and rock, it can dissolve naturally occurring minerals, pick up radionuclides, and come into contact with substances introduced by people and animals. The resulting trace contaminants are not unusual and do not automatically signal a health hazard. To keep risk low, the U.S. Environmental Protection Agency (EPA) sets legal limits for public water systems, and the Food and Drug Administration (FDA) does the same for bottled water. You can learn more from the EPA’s Safe Drinking Water Hotline at 800-426-4791.

Common contaminant categories include:

• Microbial contaminants – viruses or bacteria from sewage treatment plants, septic systems, livestock operations, and wildlife.
• Inorganic contaminants – salts and metals that occur naturally or enter water through urban storm-water runoff, industrial discharge, oil and gas production, mining, or farming.
• Pesticides and herbicides – chemicals used in agriculture, landscaping, and residential yards that can wash into streams or soak into groundwater.
• Organic chemical contaminants – synthetic and volatile compounds generated by industrial processes, petroleum production, gas stations, and septic systems.
• Radioactive contaminants – elements released from natural deposits, mining activities, or oil and gas production.

Regulated treatment, extensive monitoring, and clear public reporting—such as this Consumer Confidence Report—help ensure that Herriman’s drinking water remains well within EPA standards and safe for everyday use.