PFAS in tap water: Iwate 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

• The Morioka City water utility (盛岡市水道事業) and the bulk water supplier Oshu-Kanegasaki Administrative Association (奥州金ケ崎行政事務組合) were nd in every year they measured. Ofunato City (大船渡市), Kamaishi City (釜石市), Kuji City (久慈市) and Rikuzentakata City (陸前高田市) measure in raw water (water before treatment at the plant).
• Among private water supplies (for a facility), an exceedance has been confirmed at one national-government system: raw water at the Japan Air Self-Defense Force (JASDF) Yamada Sub Base (航空自衛隊山田分屯基地) measured 59 ng/L (the maximum from FY2020 to the end of August 2025). According to the national documents, it is being handled with water filters as an emergency measure, and removal equipment is planned to be installed during FY2025. This is a raw water value, which is not subject to the water quality standard.
• The national table shows “the highest value for each utility in that fiscal year.” → How to read the national table

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, “Results of the follow-up survey on PFOS and PFOA in water supplies” (December 25, 2025)
• Same, list of survey results (updated), Excel (annual maximums, FY2020–FY2025)
• Same, follow-up survey annex (status of private water supplies by prefecture; national-government private water supplies above the provisional target value)

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

• Aomori Prefecture
• Miyagi Prefecture
• Akita Prefecture
• Yamagata Prefecture
• Fukushima Prefecture