Tracking Water Quality in our Rivers and Lakes<\/h2>\n
Under Section 303(d) of the Clean Water Act<\/a>, states and Tribes are required to assess and report water bodies that do not meet water quality standards. These hydrologic features are classified as impaired<\/em> if they are affected by pollutants or conditions that limit their designated uses\u2014such as drinking water supply, fish consumption, recreation, and more.<\/p>\n Each state or Tribe submits its assessments to the U.S. Environmental Protection Agency (EPA), and in many cases, they also develop restoration plans that include Total Maximum Daily Loads (TMDLs)<\/a>\u2014the maximum amount of a pollutant that a water body can receive while still meeting standards.<\/p>\n The dataset includes informative pop-ups that summarize key findings from the latest study for each water body.<\/p>\n"},{"acf_fc_layout":"image","image":{"ID":2937470,"id":2937470,"title":"epa_pop-up","filename":"epa_pop-up.png","filesize":46841,"url":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2025\/08\/epa_pop-up.png","link":"https:\/\/www.esri.com\/arcgis-blog\/products\/arcgis-living-atlas\/natural-resources\/explore-epas-impaired-waters-data-in-arcgis-living-atlas-of-the-world\/epa_pop-up","alt":"","author":"9412","description":"","caption":"","name":"epa_pop-up","status":"inherit","uploaded_to":2937466,"date":"2025-08-27 14:05:10","modified":"2025-08-27 14:05:10","menu_order":0,"mime_type":"image\/png","type":"image","subtype":"png","icon":"https:\/\/www.esri.com\/arcgis-blog\/wp-includes\/images\/media\/default.png","width":442,"height":780,"sizes":{"thumbnail":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2025\/08\/epa_pop-up-213x200.png","thumbnail-width":213,"thumbnail-height":200,"medium":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2025\/08\/epa_pop-up.png","medium-width":148,"medium-height":261,"medium_large":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2025\/08\/epa_pop-up.png","medium_large-width":442,"medium_large-height":780,"large":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2025\/08\/epa_pop-up.png","large-width":442,"large-height":780,"1536x1536":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2025\/08\/epa_pop-up.png","1536x1536-width":442,"1536x1536-height":780,"2048x2048":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2025\/08\/epa_pop-up.png","2048x2048-width":442,"2048x2048-height":780,"card_image":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2025\/08\/epa_pop-up-264x465.png","card_image-width":264,"card_image-height":465,"wide_image":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2025\/08\/epa_pop-up.png","wide_image-width":442,"wide_image-height":780}},"image_position":"center","orientation":"horizontal","hyperlink":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2025\/08\/epa_pop-up.png"},{"acf_fc_layout":"content","content":" It\u2019s important to note that reporting methods vary by state. For instance, some states report impairments using subwatershed units, offering a drainage-area perspective. Other states focus on the specific water courses affected within those subwatersheds, providing a more localized view of water quality conditions.<\/p>\n"},{"acf_fc_layout":"image","image":{"ID":2937473,"id":2937473,"title":"epa_2","filename":"epa_2.png","filesize":872460,"url":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2025\/08\/epa_2.png","link":"https:\/\/www.esri.com\/arcgis-blog\/products\/arcgis-living-atlas\/natural-resources\/explore-epas-impaired-waters-data-in-arcgis-living-atlas-of-the-world\/epa_2","alt":"","author":"9412","description":"","caption":"","name":"epa_2","status":"inherit","uploaded_to":2937466,"date":"2025-08-27 14:08:44","modified":"2025-08-27 14:08:44","menu_order":0,"mime_type":"image\/png","type":"image","subtype":"png","icon":"https:\/\/www.esri.com\/arcgis-blog\/wp-includes\/images\/media\/default.png","width":780,"height":480,"sizes":{"thumbnail":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2025\/08\/epa_2-213x200.png","thumbnail-width":213,"thumbnail-height":200,"medium":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2025\/08\/epa_2.png","medium-width":424,"medium-height":261,"medium_large":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2025\/08\/epa_2.png","medium_large-width":768,"medium_large-height":473,"large":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2025\/08\/epa_2.png","large-width":780,"large-height":480,"1536x1536":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2025\/08\/epa_2.png","1536x1536-width":780,"1536x1536-height":480,"2048x2048":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2025\/08\/epa_2.png","2048x2048-width":780,"2048x2048-height":480,"card_image":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2025\/08\/epa_2-756x465.png","card_image-width":756,"card_image-height":465,"wide_image":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2025\/08\/epa_2.png","wide_image-width":780,"wide_image-height":480}},"image_position":"center","orientation":"horizontal","hyperlink":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2025\/08\/epa_2.png"},{"acf_fc_layout":"content","content":" Additionally, water courses may be classified differently across state boundaries due to differences in the types of impairments assessed or gaps in available information.<\/p>\n"},{"acf_fc_layout":"image","image":{"ID":2937474,"id":2937474,"title":"epa_3","filename":"epa_3.png","filesize":915148,"url":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2025\/08\/epa_3.png","link":"https:\/\/www.esri.com\/arcgis-blog\/products\/arcgis-living-atlas\/natural-resources\/explore-epas-impaired-waters-data-in-arcgis-living-atlas-of-the-world\/epa_3","alt":"","author":"9412","description":"","caption":"","name":"epa_3","status":"inherit","uploaded_to":2937466,"date":"2025-08-27 14:09:44","modified":"2025-08-27 14:09:44","menu_order":0,"mime_type":"image\/png","type":"image","subtype":"png","icon":"https:\/\/www.esri.com\/arcgis-blog\/wp-includes\/images\/media\/default.png","width":780,"height":430,"sizes":{"thumbnail":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2025\/08\/epa_3-213x200.png","thumbnail-width":213,"thumbnail-height":200,"medium":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2025\/08\/epa_3.png","medium-width":464,"medium-height":256,"medium_large":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2025\/08\/epa_3.png","medium_large-width":768,"medium_large-height":423,"large":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2025\/08\/epa_3.png","large-width":780,"large-height":430,"1536x1536":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2025\/08\/epa_3.png","1536x1536-width":780,"1536x1536-height":430,"2048x2048":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2025\/08\/epa_3.png","2048x2048-width":780,"2048x2048-height":430,"card_image":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2025\/08\/epa_3.png","card_image-width":780,"card_image-height":430,"wide_image":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2025\/08\/epa_3.png","wide_image-width":780,"wide_image-height":430}},"image_position":"center","orientation":"horizontal","hyperlink":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2025\/08\/epa_3.png"},{"acf_fc_layout":"content","content":" This variability reflects how each state implements the Clean Water Act, while still contributing valuable data to a unified national dataset.<\/p>\n This dataset is a valuable resource for:<\/p>\n The USA Impaired or Threatened Waterbodies<\/a> item can be easily filtered to focus on specific types of impairments. For instance, the USA Impaired or Threatened Waterbodies by Heavy Metals<\/a> item uses a view definition query<\/a> to display only features where:<\/p>\n This allows you to isolate and analyze only those water bodies impacted by heavy metals.<\/p>\n Similarly, you can create custom views based on:<\/p>\n This approach enables you to focus on the most relevant data for your analysis and integrate it into your own applications.<\/p>\n"},{"acf_fc_layout":"content","content":" Notice that the USA Polluted Waters<\/a> map service is being retired and replaced by the USA Impaired or Threatened Waterbodies<\/a> item. If you’re currently using the USA Polluted Waters<\/a> or USA Polluted Waters Heavy Metals<\/a> layers, please update your maps and applications to use the new layers<\/a>.<\/p><\/blockquote>\n The EPA Impaired Water Bodies dataset is now part of ArcGIS Living Atlas<\/a>, where it can be used alongside more than 11,000 curated layers including land cover, hydrology, climate, and infrastructure, making it a powerful resource for data-driven decision-making. Among these layers is the National Hydrography Dataset (NHD) Plus High Resolution (HR)<\/a>, which serves as a foundational layer for the EPA impaired waters dataset.<\/p>\n Visit the official Assessment, Total Maximum Daily Load (TMDL) Tracking and Implementation System (ATTAINS)<\/a> website. Interested in water resources and GIS? visit the Esri Water Resources<\/a> industry page or join the Esri Community<\/a> and ask questions to our experts.<\/p>\n"}],"authors":[{"ID":9412,"user_firstname":"Gonzalo","user_lastname":"Espinoza Davalos","nickname":"Gonzalo Espinoza","user_nicename":"gespinoza","display_name":"Gonzalo Espinoza","user_email":"gespinoza@esri.com","user_url":"http:\/\/www.gespinozadav.com","user_registered":"2019-04-04 19:02:26","user_description":"Gonzalo Espinoza specializes in hydrologic modeling, real time climate and hydro-informatic tools such as flood mapping and forecasting using National Water Model data. He masters the full geospatial tech stack required to develop scalable and operational services relying on large volumes of EO data in the fields of water and environment. Gonzalo holds a PhD in Civil Engineering from the University of Texas at Austin.\r\n\r\nFor questions about ArcGIS Living Atlas, contact environment@esri.com","user_avatar":"What You\u2019ll Find in the Pop-Up<\/h2>\n
\n
Variability in State Reporting<\/h2>\n
Use Cases<\/h2>\n
\n
Filtering by Impairments and Upcoming Layer Retirement<\/h2>\n
\n
\n
Summary<\/h2>\n
More Information<\/h2>\n
"}],"related_articles":[{"ID":2375712,"post_author":"9412","post_date":"2024-06-13 12:00:36","post_date_gmt":"2024-06-13 19:00:36","post_content":"","post_title":"Global Streamflow Forecast from GEOGLOWS Available in Living Atlas","post_excerpt":"","post_status":"publish","comment_status":"open","ping_status":"closed","post_password":"","post_name":"global-streamflow-forecast-from-geoglows-available-in-living-atlas","to_ping":"","pinged":"","post_modified":"2024-06-13 13:43:17","post_modified_gmt":"2024-06-13 20:43:17","post_content_filtered":"","post_parent":0,"guid":"https:\/\/www.esri.com\/arcgis-blog\/?post_type=blog&p=2375712","menu_order":0,"post_type":"blog","post_mime_type":"","comment_count":"0","filter":"raw"},{"ID":2498032,"post_author":"9412","post_date":"2024-10-16 11:05:36","post_date_gmt":"2024-10-16 18:05:36","post_content":"","post_title":"Announcing the Enhanced Drought Aware App in Living Atlas","post_excerpt":"","post_status":"publish","comment_status":"open","ping_status":"closed","post_password":"","post_name":"announcing-the-enhanced-drought-aware-app-in-living-atlas","to_ping":"","pinged":"","post_modified":"2024-10-16 11:06:44","post_modified_gmt":"2024-10-16 18:06:44","post_content_filtered":"","post_parent":0,"guid":"https:\/\/www.esri.com\/arcgis-blog\/?post_type=blog&p=2498032","menu_order":0,"post_type":"blog","post_mime_type":"","comment_count":"0","filter":"raw"},{"ID":1204632,"post_author":"9412","post_date":"2021-04-29 03:43:55","post_date_gmt":"2021-04-29 10:43:55","post_content":"","post_title":"Precipitation Layers in ArcGIS Living Atlas of the World","post_excerpt":"","post_status":"publish","comment_status":"open","ping_status":"closed","post_password":"","post_name":"precipitation-layers-in-arcgis-living-atlas-of-the-world","to_ping":"","pinged":"","post_modified":"2022-03-23 12:32:33","post_modified_gmt":"2022-03-23 19:32:33","post_content_filtered":"","post_parent":0,"guid":"https:\/\/www.esri.com\/arcgis-blog\/?post_type=blog&p=1204632","menu_order":0,"post_type":"blog","post_mime_type":"","comment_count":"0","filter":"raw"},{"ID":1528442,"post_author":"9412","post_date":"2022-03-31 09:00:16","post_date_gmt":"2022-03-31 16:00:16","post_content":"","post_title":"Evapotranspiration Data in ArcGIS Living Atlas of the World","post_excerpt":"","post_status":"publish","comment_status":"open","ping_status":"closed","post_password":"","post_name":"evapotranspiration-data-in-arcgis-living-atlas-of-the-world","to_ping":"","pinged":"","post_modified":"2024-08-12 12:35:13","post_modified_gmt":"2024-08-12 19:35:13","post_content_filtered":"","post_parent":0,"guid":"https:\/\/www.esri.com\/arcgis-blog\/?post_type=blog&p=1528442","menu_order":0,"post_type":"blog","post_mime_type":"","comment_count":"1","filter":"raw"}],"show_article_image":false,"card_image":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2025\/08\/epa_card.jpg","wide_image":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2025\/08\/epa_banner.jpg"},"yoast_head":"\n