Water Quality [Washington (State)]
State of Washington Geospatial Open Data Portal · 2025 Full Details
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Full Details
- Title
- Water Quality [Washington (State)]
- Description
- This data is included as part of the Environmental Health Disparities Version 3.0 map. To see this map, visit our webpage . For more technical information on this map and the model used, visit our technical report (link) . Background Water is vital for drinking, aquatic life, agriculture, and recreation. It is also crucial for ecosystems and has cultural significance. This measure assesses the quality of waterbodies, which can affect aquatic life and impact human and animal health. For example, pollutants like dioxins can impact the reproduction and development of both people and fish. People who use well water are more affected by environmental water quality because their water is not treated or regulated like water from municipal systems. Water quality and health risk vary by location. This puts some communities at greater risk. These communities often have less economic access and more people of color. Testing w ater quality is important for the health of humans, animals and aquatic life. Under the federal Clean Water Act, all states must keep a list of polluted waters. In Washington, the Department of Ecology (ECY) assesses waterbodies based on the credible data submitted to the agency. From the data that is submitted, Ecology determines which waters are polluted, which are clean, and which do not have enough data to make a determination. Assessing water quality helps find where water is most impacted by pollutants. This information guides water quality improvement plans. Evidence Polluted water is linked to sickness in both humans and animals, aquatic habitat damage, and bad smells [1, 2]. Communities with both less economic access and more of people of color often face more pollution in their waters [3]. Climate extremes, such as droughts, can impact water quality by concentrating pollutants and increasing water temperature. This can affect health and safety [4]. Heavy rain can also wash pollutants into waterways [5]. Data source Washington State Ecology Water Quality Atlas: Water Quality Atlas - Start Page Washington State Ecology Water Quality Assessment: Assessment of state waters 303d - Washington State Department of Ecology Method This measur e displays the total number of unique pollutants in each census tract, based on findings from all water bodies within that tract assessed by ECY as falling under categories 4a, 4b, or 5. This measure is modeled after CalEnviroScreen's Impaired Water Bodies Measure. Caveats This measure is not comprehensive. Areas that do not have the resources for water assessment, or that capture their water quality by different metrics, are not included. This measure should be used as a starting point, and not as a sole basis for funding decisions. Water quality on Tribal lands i s not included. Tribal governments have requested that Ecology not assess Tribal waters as part of the State's Water Quality Assessment. Some Tribes in Washington have their own Clean Water Act standards. We plan to confer with Tribes about their level of interest in exploring a process for including their data in this measure, and how we might collaborate on other ways Tribes would like water quality to be represented. This measure represents the entire ce nsus tra ct, no t indiv idual areas wit hin it. These data should always be supplemented with local data and equitable engagement for more accurate insights. Additional Resources California Office of Environmental Health Hazard Assessment CalEnviroScreen, Impaired Water Bodies Northwest Indian Fisheries Commission, New home for Treaty Rights at Risk Tribal Water Quality Resources: EPA Actions on Tribal Water Quality Standards and Contacts , US EPA, FAQs CWA TAS IR , US EPA ARCHIVE DOCUMENT Washington State Department of Ecology, Water Quality Water Quality Standards: Water quality standards - Washington State Department of Ecology Ecology Data Credibility Standards: Water Quality Policy 1-11 Chapter 2. Ensuring Credible Data for Water Quality Management Sources Lin, L., Yang, H., & Xu, X. (2022). Effects of water pollution on human health and disease heterogeneity: a review. Frontiers in environmental science , 10 , 880246. Haxton, T. J., & Findlay, C. S. (2008). Meta-analysis of the impacts of water management on aquatic communities. Canadian Journal of Fisheries and Aquatic Sciences , 65 (3), 437-447. Liévanos, R. S. (2018). Impaired Water Hazard Zones: Mapping Intersecting Environmental Health Vulnerabilities and Polluter Disproportionality. ISPRS International Journal of Geo-Information , 7 (11), 433. https://doi.org/10.3390/ijgi7110433 Health impacts of drought . (2024, March 28). Drought and Health. https://www.cdc.gov/drought-health/health-implications/index.html National Climate Assessment. (2023.). National Climate Assessment. https://nca2014.globalchange.gov/ Citation Washington Tracking Network, Washington State Department of Health. Web. "Water Quality". Data obtained from the Department of Ecology, 2018 Water Quality Assessment Data. Published September 2025.
- Creator
- WADOH
- Publisher
- State of Washington Geospatial Open Data Portal
- Temporal Coverage
- Last Modified: 2025-07-16
- Date Issued
- 2025-07-08
- Rights
- Neither the Washington State Department of Health (WADOH), nor any agency, officer, or employee of the WADOH warrants the accuracy, reliability or timeliness of any information published by this system, nor endorses any content, viewpoints, products, or services linked from this system, and shall not be held liable for any losses caused by reliance on the accuracy, reliability, or timeliness of such information. Portions of such information may be incorrect or not current. Any person or entity who relies on any information obtained from this system does so at their own risk.
- Access Rights
- Public
- Format
- ArcGIS FeatureLayer
- Language
- English
- Date Added
- February 02, 2026
- Provenance Statement
- The metadata for this resource was last retrieved from State of Washington Geospatial Open Data Portal on 2026-02-02.
Cite and Reference
-
Citation
WADOH (2025). Water Quality [Washington (State)]. State of Washington Geospatial Open Data Portal. https://geo.wa.gov/datasets/cc2d461afcac47368c3351971f73c258_0 (web service) -
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