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About Drinking Water Contaminants Data

Overview

This site provides data about common drinking water contaminants: arsenic, atrazine, perchloroethene (PCE), trichloroethene (TCE), di(2-ethylhexyl)phthalate (DEHP), trihalomethanes (TTHM), haloacetic acids (HAA5), nitrate, perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), 1,4-dioxane, radium and uranium. Data are presented for each public water system by year and in some cases by quarter. The table below shows key information about drinking water data.

Data Source	Safe Drinking Water Information System (SDWIS) Suffolk County Department of Health Services Suffolk County Water Authority
Time Frame	2000-2022
Geographic Coverage	New York State by Water System
Last Update	April 2023
Data Methodology	See Technical Notes

Interpreting Data

The Environmental Public Health Tracker presents New York State drinking water data collected by individual public water systems by contaminant and year. Data reported to NYS Safe Drinking Water Information system is reported to EPA’s national database that manages and collects monitoring and compliance information. Suffolk County and New York City water system data are maintained in separate information systems.
Public water systems are listed by county. Public drinking water monitoring is used to ensure that drinking water meets public health standards and helps inform people about water contaminant levels in their water system. More about New York State Drinking Water Protection Program.
New York State regulates how often public water systems monitor their water for contaminants and report the monitoring results to the local health departments and the State according to both federal Safe Drinking Water Act requirements and specific state regulations. Generally, the larger the population served by a water system, the more frequent the monitoring and reporting requirements are. When specific contaminants are detected, water systems are often required to sample and report more often than those who have not found contaminants. When a system’s contaminant levels exceed public health standards, corrective action is required, and more frequent sampling may be mandated. Find out more about Public Water Supply Compliance Reports.
Environmental Public Health Tracker data are not used for compliance determination with section 1414(c)(3) of the Safe Drinking Water Act or Part 5 of the State Sanitary Code, or for evaluating the system's return to compliance. The table data are presented based on average and maximum analytical results without consideration of non-compliance with health standards - the focus here is on level of specific contaminants found in individual water systems. However, the map colors indicate whether maximum contaminant levels (MCLs) are exceeded or not. MCLs are regulatory limits that are set far below levels that cause health effects.
The Environmental Public Health Tracker data present summary values for each water system, while contaminant levels may vary within a system. For Nitrate and arsenic, levels may vary depending on how close the consumer is to a specific well for groundwater systems with multiple wells. For disinfection by-products, levels may vary depending on how far a consumer is from a treatment plant that adds chlorine (or other disinfectants) and the level of natural organic material in source water, which may vary by season for surface water systems. For PFOA, PFOS and 1,4-dioxane, the data presented may be source water monitoring data prior to any available treatment or being delivered to the customer. Data may also include water sources that are out of service. As a result, these data may not reflect the actual levels that people are drinking. People should always contact their water supplier or refer to their Annual Water Quality Report to find out more about levels of contaminants in finished drinking water.
All data are for public drinking water and do not include private well water data.

View Statewide Water System Data

Users can view local water systems by contaminant, average concentration measures, maximum concentration measures, and either an annual or quarterly reporting period. Users can view a map, charts and results showing the selected drinking water contaminants by concentration, measure, period and population served by county. Not all contaminants display quarterly concentration reports, and the maximum concentration measure is not available for quarterly concentration reports.

The Statewide Water System Map view allows users to interact with it in several ways: 1) Zoom the map to the extent of a particular county boundary by selecting a county from the drop-down list at the bottom of the map and hitting the Zoom to County button. 2) In county view, get contaminant information for a particular water system by clicking on a water system, which will result in an identify window displaying the information you want for that system. Data tables show population and concentrations by individual water systems by county.

1,4-Dioxane by Water System, Measure and Reporting Period

Users can view average and maximum 1,4-dioxane concentrations annually by water system in New York State. Users can also view average 1,4-dioxane concentrations quarterly by water system in New York State. The data presented may be source water monitoring data prior to any available treatment or being delivered to the customer. Data may also include water sources that are out of service. As a result, these data may not reflect the actual levels that people are drinking. People should always contact their water supplier or refer to their Annual Water Quality Report to find out more about levels of contaminants in finished drinking water.

Arsenic by Water System, Measure and Reporting Period

Users can view average and maximum arsenic concentrations by water system annually in New York State.

Atrazine by Water System, Measure and Reporting Period

Users can view average and maximum atrazine concentrations by water system annually in New York State. Users can also view average Atrazine concentrations quarterly by water system in New York State.

Di(2-ethylhexyl)phthalate (DEHP) by Water System, Measure and Reporting Period

Users can view average and maximum DEHP concentrations annually by water system in New York State.

Halocetic Acids (HAA5) by Water System, Measure and Reporting Period

Users can view average and maximum HAA5 concentrations annually by water system in New York State. Users can also view average HAA5 concentrations quarterly by water system in New York State.

Nitrate, by Water System, Measure and Reporting Period

Users can view average and maximum Nitrate concentrations annually by water system in New York State. Users can also view average Nitrate concentrations quarterly by water system in New York State.

Perchloroethene (PCE) by Water System, Measure and Reporting Period

Users can view average and maximum PCE concentrations annually by water system in New York State.

Perfluorooctanoic acid (PFOA), by Water System, Measure and Reporting Period

Users can view average and maximum PFOA concentrations annually by water system in New York State. Users can also view average PFOA concentrations quarterly by water system in New York State. The data presented may be source water monitoring data prior to any available treatment or being delivered to the customer. Data may also include water sources that are out of service. As a result, these data may not reflect the actual levels that people are drinking. People should always contact their water supplier or refer to their Annual Water Quality Report to find out more about levels of contaminants in finished drinking water.

Perfluorooctane sulfonic acid (PFOS), by Water System, Measure and Reporting Period

Users can view average and maximum PFOS concentrations annually by water system in New York State. Users can also view average PFOS concentrations quarterly by water system in New York State. The data presented may be source water monitoring data prior to any available treatment or being delivered to the customer. Data may also include water sources that are out of service. As a result, these data may not reflect the actual levels that people are drinking. People should always contact their water supplier or refer to their Annual Water Quality Report to find out more about levels of contaminants in finished drinking water.

Radium by Water System, Measure and Reporting Period

Users can view average and maximum radium concentrations annually by water system in New York State.

Trichloroethene (TCE) by Water System, Measure and Reporting Period

Users can view average and maximum TCE concentrations annually by water system in New York State.

Trihalomethanes (TTHM) by Water System, Measure and Reporting Period

Users can view average and maximum TTHM concentrations annually by water system in New York State. Users can also view average TTHM concentrations quarterly by water system in New York State.

Uranium by Water System, Measure and Reporting Period

Users can view average and maximum Uranium concentrations annually by water system in New York State.

View Statewide Summary Charts

Users can view charts and tables showing contaminants, average concentration measures, maximum concentration measures, and either an annual or quarterly reporting period by the number of people in all of New York State served by public water systems with drinking water containing selected contaminant concentrations.

These displays focus on the number of people potentially exposed to mid and high concentrations of contaminants. These data are broken out by individual water system in the Water System Data Table below each Summary Table.

1,4-Dioxane by Measure and Reporting Period, Statewide

Users can view bar charts displaying the number of people served by water systems reporting annual average and maximum 1,4-dioxane concentrations at each level in New York State. The data presented may be source water monitoring data prior to any available treatment or being delivered to the customer. Data may also include water sources that are out of service. As a result, these data may not reflect the actual levels that people are drinking. People should always contact their water supplier or refer to their Annual Water Quality Report to find out more about levels of contaminants in finished drinking water.

Arsenic by Measure and Reporting Period, Statewide

Users can view bar charts displaying the number of people served by water systems reporting annual average and maximum arsenic concentrations at each level in New York State.

Atrazine by Measure and Reporting Period, Statewide

Users can view bar charts displaying the number of people served by water systems reporting annual average and maximum atrazine concentrations at each level in New York State. Users can also view bar charts displaying the number of people served by water systems reporting quarterly average Atrazine concentrations at each level in New York State.

Di(2-ethylhexyl)phthalate (DEHP) by Measure and Reporting Period, Statewide

Users can view bar charts displaying the number of people served by water systems reporting annual average and maximum DEHP concentrations at each level in New York State.

Halocetic Acids (HAA5) by Measure and Reporting Period, Statewide

Users can view bar charts displaying the number of people served by water systems reporting annual average and maximum HAA5 concentrations at each level in New York State. Users can also view bar charts displaying the number of people served by water systems reporting quarterly average HAA5 concentrations at each level in New York State.

Nitrate by Measure and Reporting Period, Statewide

Users can view bar charts displaying the number of people served by water systems reporting annual average and maximum nitrate concentrations at each level in New York State. Users can also view bar charts displaying the number of people served by water systems reporting quarterly average nitrate concentrations at each level in New York State.

Perchloroethene (PCE) by Measure and Reporting Period, Statewide

Users can view bar charts displaying the number of people served by water systems reporting annual average and maximum PCE concentrations at each level in New York State.

Perfluorooctanoic acid (PFOA) by Measure and Reporting Period, Statewide

Users can view bar charts displaying the number of people served by water systems reporting annual average and maximum PFOA concentrations at each level in New York State. The data presented may be source water monitoring data prior to any available treatment or being delivered to the customer. Data may also include water sources that are out of service. As a result, these data may not reflect the actual levels that people are drinking. People should always contact their water supplier or refer to their Annual Water Quality Report to find out more about levels of contaminants in finished drinking water.

Perfluorooctane sulfonic acid (PFOS) by Measure and Reporting Period, Statewide

Users can view bar charts displaying the number of people served by water systems reporting annual average and maximum PFOS concentrations at each level in New York State. the data presented are initial source water monitoring data prior to any available treatment or being delivered to the customer. The data presented may be source water monitoring data prior to any available treatment or being delivered to the customer. Data may also include water sources that are out of service. As a result, these data may not reflect the actual levels that people are drinking. People should always contact their water supplier or refer to their Annual Water Quality Report to find out more about levels of contaminants in finished drinking water.

Radium by Measure and Reporting Period, Statewide

Users can view bar charts displaying the number of people served by water systems reporting annual average and maximum radium concentrations at each level in New York State.

Trichloroethene (TCE) by Measure and Reporting Period, Statewide

Users can view bar charts displaying the number of people served by water systems reporting annual average and maximum TCE concentrations at each level in New York State.

Trihalomethanes (TTHM) by Measure and Reporting Period, Statewide

Users can view bar charts displaying the number of people served by water systems reporting annual average and maximum TTHM concentrations at each level in New York State. Users can also view bar charts displaying the number of people served by water systems reporting quarterly average TTHM concentrations at each level in New York State.

Uranium by Measure and Reporting Period, Statewide

Users can view bar charts displaying the number of people served by water systems reporting annual average and maximum uranium concentrations at each level in New York State.

View County Water System Results

Users can select a county from all counties in New York State to view a table of all contaminants, measures, annual and quarterly reporting periods by water system in that county.

Technical Notes

Public water systems that reported concentrations below the detection limit for that analyte (or contaminant) are reported as half the detection limit and show in range as non-detect or "ND". For more information on specific local water systems contact your water supply provider.
In 2006, regulations on disinfection by-product sampling changed the location and number of samples taken; these changes, reflected in the data, do not necessarily mean exposure to DBPs is increasing.
In 2020, New York State added regulations for PFOA, PFOS and 1,4-dioxane. These additions to the data do not mean that exposure to these contaminants is new or increasing. In addition, because PFOA, PFOS and 1,4-dioxane are new regulated contaminants, the data presented may be source water monitoring data prior to any available treatment or being delivered to the customer. Data may also include water sources that are out of service. As a result, these data may not reflect the actual levels that people are drinking. People should always contact their water supplier or refer to their Annual Water Quality Report to find out more about levels of contaminants in finished drinking water.

On Calculating Population:

System populations reported here reflect the number of residents for that system - reported counts do not include transitory populations such as daily workforce commuters. Indicators are calculated using the most recent population estimate available. While populations do fluctuate over time this should not have a significant impact on the display of population served by public water supplies.

On Calculating Indicators:

For systems with very low levels of a selected contaminant, sampling requirements may be reduced so that a sample was not taken in the year selected. In these cases, the last available sample result is presented as the value representing the selected year.

Department of Health