How Do Contaminants Get in the Water Supply?
The sources of drinking water( both tap water and bottled water) include rivers, lakes, streams, ponds, reservoirs, springs, and wells. As water travels over the surface of the land or through the ground, it dissolves naturally occurring minerals and, in some cases, radioactive material, and can pick up substances resulting from the presence of animals or human activity.
Contaminants that may be present in source water include:
Inorganic contaminants: Includes salts and metals, which can be naturally occurring or result from urban stormwater runoff, industrial or domestic wastewater discharges, oil and gas production, mining, or farming.
Microbial contaminants: Includes viruses and bacteria, and may come from sewage treatment plants, septic systems, agricultural livestock operations and wildlife.
Organic chemical contaminants: Includes synthetic and volatile organic chemicals, which are by-products of industrial processes, and can also come from gas stations, urban stormwater runoff and septic systems.
Pesticides and herbicides: Come from a variety of sources such as agriculture, urban stormwater runoff and residential uses.
Radioactive contaminants: Can be naturally occurring or be the result of oil and gas production and mining activities.
Contaminant Regulations
To ensure that tap water is safe to drink, the EPA prescribes regulations, which limit the amount of certain contaminants in water provided by public water systems. The U. S. Food and Drug Administration( FDA) regulations establish limits for contaminants in bottled water, which must provide the same protection for public health.
Ensuring Water is Safe to Drink
Your water is monitored for many substances on a strict sampling schedule to ensure it meets specific health standards and maintains the high quality that residents know and expect.
The tables included in this report list substances that may be found in your tap water, as well as the U. S. Environmental Protection Agency’ s( EPA) established acceptable levels of these contaminants.
Keep in Mind
• The State allows some contaminants to be monitored less often than once per year because the concentration of these elements does not change frequently. In these instances, the most recent sample data is included along with the year in which the sample was taken.
• Drinking water, including bottled water, may reasonably be expected to contain at least small amounts of some contaminants. The presence of contaminants does not necessarily indicate that the water poses a health risk. More information about contaminants and potential health effects can be obtained by calling the Environmental Protection Agency’ s Safe Drinking Water Hotline at 1-800-426-4791.
Understanding Our Test Results
Below are definitions of the terms used in this report.
Action Level( AL): The concentration of a contaminant that, if exceeded, triggers treatment or other requirements that a water system must follow.
Contaminant: Any unwanted physical, chemical, biological or radiological substance or matter in water.
Maximum Contaminant Level or MCL: The highest level of a contaminant that is allowed in drinking water. MCLs are set as close to the MCLGs as feasible using the best available treatment technology.
Maximum Contaminant Level Goal or 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.
Maximum Residual Disinfectant Level or MRDL: The highest level of a disinfectant allowed in drinking water. There is convincing evidence that the addition of a disinfectant is necessary for control of microbial contaminants.
Maximum Residual Disinfectant Level Goal or 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.
N / A: Not applicable ND: Not detected and indicates that the substance was not found by laboratory analysis. Picocurie Per Liter( pCi / L): Measure of the radioactivity in water.
Parts Per Billion( PPB) or Micrograms Per Liter( mg / l): One part by weight of analyte to 1 billion parts by weight of the water sample.
Parts Per Million( PPM) or Milligrams Per Liter( mg / l): One part by weight of analyte to 1 million parts by weight of the water sample.
What is PPM? Many of the utilities’ test results are reported as“ parts per million”( ppm) or“ parts per billions( ppb).
PPM( Parts Per Million)
Means one part per 1,000,000 parts. This is equivalent to two thirds of a gallon in an Olympic-sized swimming pool which holds 660,000 gallons.
PPB( Parts Per Billion)
Means one part per 1,000,000,000 parts. This is equivalent to half of a teaspoon in an Olympicsized swimming pool.