PFAS in tap water: Miyazaki 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 prefecture tested 6 wells and 3 river points within about 500 m of Kobayashi City’s water source, and 1 well on the east side had 200 ng/L (above the guideline value). The rivers had 9.8–12. The prefecture says it will survey along the direction of groundwater flow to identify the area that exceeds the value (announcement of October 23, 2025). The announcement does not state a cause.
• In the November 2024 table, 43 of the prefecture’s 76 rows were measured only in raw water (water before treatment). The 15 for Nichinan City (日南市) (FY2024) was measured only in raw water. The 17 for Aya Town (綾町) and the 12 for Miyakonojo City (都城市) (both FY2025) are values for utilities whose testing point was “raw water only” in the November 2024 table (the table does not list the testing points for the FY2025 values). A raw water value is not necessarily the value of the water delivered to homes.
• There are 46 private water supplies (for a facility: in-house water systems for company housing, hospitals, bases and so on). Of the 26 that were tested, 1 exceeded 50: the private water supply set up by the national government at JASDF Nyutabaru Air Base (航空自衛隊新田原基地), 560 ng/L (raw water). A national document says it was “switched to the public water supply.”
• The national document of December 2025 says that of the 19 utilities nationwide that have exceeded 50, 18 have taken measures and 1 is still under emergency response, but it does not say which utility that is.

Rivers and groundwater (environmental monitoring)

These measure rivers or groundwater themselves, not tap water. The water is not necessarily used for drinking.

• The 200 ng/L in a well near Kobayashi City’s water source came from the prefecture’s groundwater (well) survey. The guideline value is a benchmark for rivers and groundwater and is separate from the tap water standard. → High levels in rivers or groundwater = high levels in tap water?

Put it in terms of your own intake

Related explainers

• What happened in areas where high PFAS values were found in tap water? A timeline of Kibichuo, Tama, Okinawa and more
• 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
• Water filters and PFAS

Sources

• Ministry of the Environment and MLIT: List of results of the follow-up survey of PFOS and PFOA in water supplies (published December 25, 2025)
• Ministry of the Environment and MLIT: Results of the follow-up survey (December 25, 2025; including exceedances at private water supplies set up by the national government)
• Miyazaki Prefecture: “Results of the PFAS survey around Kobayashi City’s tap water source” (October 23, 2025)
• Ministry of the Environment and MLIT: List of survey results (published November 29, 2024; testing point column)

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

• Fukuoka Prefecture
• Saga Prefecture
• Nagasaki Prefecture
• Kumamoto Prefecture
• Oita Prefecture
• Kagoshima Prefecture