Official Water Quality Resources
All the official sources, certification bodies, and research institutions we cite throughout Filter Authority—organized in one place for easy reference.
UK Government & Regulatory Bodies
Drinking Water Inspectorate (DWI)
Independent regulator of drinking water quality in England and Wales. Publishes annual compliance reports, triennial reviews, and water quality data by region.
Visit DWI WebsiteKey Resources:
Ofwat (Water Services Regulation Authority)
Economic regulator of the water sector in England and Wales. Monitors water company performance, sets price controls, and enforces penalties for failures.
Visit Ofwat WebsiteEnvironment Agency
Protects and improves the environment in England. Monitors water quality in rivers, lakes, and groundwater. Regulates water abstraction and pollution.
Visit Environment AgencyDAERA Northern Ireland
Department of Agriculture, Environment and Rural Affairs. Regulates drinking water quality in Northern Ireland through the Drinking Water Inspectorate for Northern Ireland.
Visit DAERA WebsiteCertification & Testing Standards
NSF International
Independent organization that develops public health standards and certifies products. NSF/ANSI standards 42, 53, 58, and 401 are the gold standard for water filter testing.
Visit NSF InternationalKey Standards:
- • NSF/ANSI 42: Aesthetic effects (taste, odor, chlorine)
- • NSF/ANSI 53: Health effects (lead, cysts, VOCs)
- • NSF/ANSI 58: Reverse osmosis systems
- • NSF/ANSI 401: Emerging contaminants (PFAS, pharmaceuticals)
Water Quality Association (WQA)
International trade association representing the water treatment industry. Provides Gold Seal certification for water treatment products and systems.
Visit WQA WebsiteMajor UK Water Companies
Research & Health Organizations
Environmental Working Group (EWG)
Non-profit research organization focused on environmental health. Publishes tap water database and research on emerging contaminants like PFAS.
Visit EWG WebsiteUS CDC / ATSDR
Centers for Disease Control and Prevention / Agency for Toxic Substances and Disease Registry. Publishes health effects research on water contaminants including PFAS.
Visit ATSDR PFAS PageUS EPA (Environmental Protection Agency)
Sets drinking water standards in the United States. Often ahead of UK regulations on emerging contaminants. Publishes extensive research on water quality and treatment.
Visit EPA Drinking WaterPubMed / NIH
US National Library of Medicine database of peer-reviewed biomedical research. Search for studies on water contaminants, microplastics, and health effects.
Visit PubMedAbout These Links
All links on this page are checked quarterly (March, June, September, December) to ensure they remain active and accurate. Government websites occasionally restructure their URLs or move content.
Last Link Check: December 2025 | Next Check: March 2026
If you encounter a broken link, please contact us and we'll update it promptly.