skip navigation
Health EffectsEnvironmental HazardsTopics A-ZTopics A-ZPublicationsResourcesFrequently Asked QuestionsAbout Us
NH Environmental Public Health Tracking Program
Environmental Public Health Tracking Data
 

Key Contaminants in Public Drinking Water

New Hampshire community water systems (public water suppliers) are required to provide drinking water that meets federal standards established under the federal Safe Drinking Water Act (SDWA). NH Department of Environmental Services (DES) is the agency designated to supervise public water systems under SDWA, including maximum contaminant levels (MCLs), monitoring schedules, and water system inspections.

Three types of indicators are used to track public drinking water: public water use measures, level of contaminant, and potential population exposure. The public water use measures provide information about the segment of the population to which the measures apply. The level of contaminant shows how well the water systems are producing high-quality water. The potential population exposure measures use estimates of the population served by water supplies to show the potential for exposure to contaminants in drinking water on a population basis. These measures together indicate the potential for public health impacts from contaminant levels of concern.

The EPHT Program uses public drinking water data provided by the NH DES to compile nationally consistent measures for the following key contaminants in public drinking water: arsenic, disinfection by-products, lead, and nitrates/nitrites. NCDMS are used by the national Environmental Public Health Tracking Network for comparison state-wide. These measures are available on the Environmental Health Data Integration Network (EHDIN).

Measures for Key Contaminants in Public Drinking Water

1. Population Served By Community Water Systems (CWS)

A. Disinfection by-products (DBP)

  1. Number and percent of community water system with any DBP MCL violation, by year
  2. Number and percent of community water system with any DBP MCL violation, by quarter
  3. Number and percent of community water systems by the number of DBP MCL violations the system had each year

B. Arsenic

  1. Number and percent of community water system with any arsenic MCL violation, by year
  2. Distribution of mean arsenic concentrations across community water system, by 3-year compliance (sampling) period (cut-points: <3, 5, 10, 15, >15 ppb arsenic)

C. Lead

  1. Number and percent of community water system with any action level exceedance, by year. (NOTE: An Action Level (AL) exceedence is not an MCL violation.)

D. Nitrate

  1. Number and % of community water system with any nitrate MCL violation, by year
  2. Distribution of mean nitrate concentration across community water system, by year (cut points: <=1, 3, 5, 10, 20, >20 mg/l nitrate-nitrogen)
  3. Distribution of maximum nitrate concentration across community water system, by year (cut points: <=1, 3, 5, 10, 20, >20 mg/l nitrate-nitrogen)

2. Potential Population Exposure to Contaminants in Finished Drinking Water

A. Disinfection by-products (DBP)

  1. Number and percent of people served by community water system with any DBP MCL violation, by year
  2. Number and percent of people served by community water system with any DBP MCL violation, by quarter
  3. Number and percent of people receiving water from community water system by the number of DBP MCL violations the system had each year.
  4. Percent of person-months for which no DBP violation occurred, by year
  5. Number and percent of people receiving water from community water system with a mean DBP concentration greater than specific reference levels. Reference levels will be the 50th, 75th, 90th and 95th percentiles of the distribution of mean DBP levels in 2005.
  6. Distribution of number of people by mean DBP concentration, by quarter and year

B. Arsenic

  1. Number and percent of people served by community water system with any arsenic MCL violation, by year
  2. Distribution of number of people by mean arsenic concentration, by 3-year compliance (sampling) period (cumulative frequency distribution).

C. Lead

(NOTE: Due to the nature of the lead sampling, no measure linking population data by community water system is being recommended for lead at this time.)

D. Nitrate

  1. Number and percent of people served by community water system with any nitrate MCL violation, by year
  2. Distribution of number of people by mean nitrate concentration of finished water, by year (cut points: <=1, 3, 5, 10, 20, >20 mg/l nitrate-nitrogen)
  3. Distribution of number of people by maximum nitrate concentration of finished water, by year (cut points: <=1, 3, 5, 10, 20, >20 mg/l nitrate-nitrogen)

For more information about public drinking water.

For specific information about key contaminants in public drinking water:

logo_ehdin GET EPHT DATA

Environmental Public Health Tracking Program
NH Department of Health and Human Services, Division of Public Health Services
29 Hazen Drive, Concord, NH 03301
Tel: (603) 271-4988 800-852-3345 ext.4988

copyright 2009. State of New Hampshire