PFAS in tap water: Fukui Prefecture

Levels by utility (PFOS + PFOA combined, ng/L)

These are the highest values in each fiscal year reported by each utility to the national government (MLIT and the Ministry of the Environment). A utility with several sources or treatment plants can have different levels in different parts of its area. Samples are taken at the tap in principle, but some utilities only measured raw water (water before treatment), and raw-water values are not covered by the tap-water standard. nd = below the detection or quantification limit; — = no value reported. *FY2025 covers results up to the end of August 2025. Utility names are left in Japanese as in the official table.

>50 a year above 50 ng/L (for utilities that also sampled raw water, the value may be from raw water)　raw above 50 ng/L, but measured in raw water only

Good to know

• Of the 66 rows with a value for FY2024, 65 were nd (below the quantification limit, the smallest amount that can be measured). The only supplier with a number was the Awara Onsen Water Supply Property District waterworks, whose testing points are the tap and raw water (before treatment) (table published in 2024). Fukui City Waterworks (福井市水道事業) reported 8 (FY2021–FY2023), then nd in FY2024 and FY2025.
• Among private water supplies (for a facility, such as company housing, hospitals and schools), 1 of the 11 operators tested in the prefecture exceeded the provisional target value (50 ng/L) (FY2020 through the end of August 2025). The facility is not named in the national documents.
• In FY2025, 4 rows say “to be tested within the fiscal year,” and no value is listed yet. The national table gives only one value per supplier per year (the maximum), so check each supplier’s own water quality reports for details. → How to check

Put it in terms of your own intake

Related explainers

• How do you check PFAS in your local tap water? Reading the national tables and working out “what percent of the TDI”
• Japan’s PFAS standard for tap water, “50 ng/L”: how was it set, and how does it differ from the U.S. and EU?
• Water filters and PFAS

Sources

• Ministry of the Environment and MLIT, “Survey on PFOS and PFOA in Water Supply,” follow-up survey: list of results (published December 25, 2025)
• Ministry of the Environment and MLIT, list of results (published November 29, 2024; testing point column)
• Same follow-up survey, attachment (status of private water supplies by prefecture)

Last checked 2026.10.04 (against the original government documents and papers, collected and cross-checked in Gemini Notebook). Utility values are as in the national table; Urayomi sorted and summarized them.

Other prefectures

• Niigata Prefecture
• Toyama Prefecture
• Ishikawa Prefecture
• Yamanashi Prefecture
• Nagano Prefecture
• Gifu Prefecture
• Shizuoka Prefecture
• Aichi Prefecture