PFAS in tap water: Shizuoka 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

• Shizuoka City Waterworks (静岡市水道事業) reported 7 (FY2020), nd, 11, 8, 14 and 17 (FY2025), with testing points at the tap and the treatment plant outlet. Hamamatsu City Waterworks (浜松市水道事業) was nd (below the quantification limit) in every year from FY2020 to FY2025.
• Numazu City Waterworks (沼津市水道事業) was also nd in all six years, but its testing point is “raw water only” (raw water = water before treatment) in the table published in 2024. Of the 143 rows for the prefecture, 26 are “raw water only.”
• The prefecture’s four bulk water suppliers (which sell water to municipalities) — the Oigawa Regional Water Supply Authority (大井川広域水道企業団), Sunzu (駿豆), Shinnan (榛南) and Enshu (遠州) — were all nd, except 0.2–0.5 ng/L at the Oigawa Regional Water Supply Authority.
• In FY2024, 73 of the 100 rows with a value were nd; in FY2025, 61 of the 80 were nd. In FY2025, another 6 rows say “to be tested within the fiscal year.”
• Among private water supplies (for a facility, such as company housing or hospitals), none of the 192 tested in the prefecture was found to exceed the provisional target value (50 ng/L) (through the end of August 2025).
• The national table gives only one value per supplier per year (the maximum). For suppliers with more than one treatment plant, values can differ depending on which plant your water comes from (the supply line). → 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”
• Do high PFAS values in rivers or groundwater mean high values in tap water? How guideline values differ from the tap water standard
• 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
• Fukui Prefecture
• Yamanashi Prefecture
• Nagano Prefecture
• Gifu Prefecture
• Aichi Prefecture