89 records

What is the PFAS drinking water limit in my state?

89 records, one fact each. Every value is transcribed from the source that states it and carries the sentence it was taken from: 5 sources across 5 sites, last checked 2026-08-14, due for re-check by 2027-02-10. Every record is listed below, each linking the page its value came from.

About this data

State-by-state comparison of legally enforceable and advisory concentration limits for PFAS compounds in drinking water. Each record is one state–chemical pair with the concentration limit (in parts per trillion), the regulation type (MCL, notification level, action level, health advisory, or guideline), the effective date, the statutory or regulatory citation, and whether the state limit is stricter than the federal EPA MCL. The federal MCLs are 4 ppt for PFOA and PFOS (affirmed May 2025); EPA proposed rescinding the MCLs for PFHxS, PFNA and HFPO-DA on 18 May 2026, but that is a proposal only and those MCLs still stand. State limits range from 3 ppt (California, PFHxS) to 400,000 ppt (Michigan, PFHxA). Only drinking water limits are in scope — contaminated-site screening values and groundwater quality standards are excluded even where a state publishes them for the same compounds. Answers 'what is the legal PFAS limit in my state', 'is my state stricter than the federal standard', and 'which PFAS compounds does my state regulate'.

The data

Where this came from

Every record above links the page it was taken from and quotes the sentence that states it. These are the 5 sources this dataset was assembled from.

• bclplaw.comhttps://www.bclplaw.com/en-US/events-insights-news/pfas-drinking-water-standards-state-by-state-regulations.html
• epa.govhttps://www.epa.gov/sdwa/and-polyfluoroalkyl-substances-pfas
• maine.govhttps://www.maine.gov/dep/spills/topics/pfas/
• michigan.govhttps://www.michigan.gov/pfasresponse/drinking-water/mcl
• health.ri.govhttps://health.ri.gov/water/about/pfas/

Machine-readable

• data.jsonThe whole dataset — every record with its source URL and source quote.
• Open Knowledge Format bundleOne JSON object per line — every record's frontmatter and quoted span exactly as it is held here, in one fetch.
• data.csvThe same records as one flat table, for a spreadsheet or a dataframe. The last four columns are the source URL, the quoted sentence it was read from, the date we last checked it, and which columns are our reading rather than the page's words.
• How this is made and checkedWhat "verified against source" does and does not mean.

From your own code

Same records, same quotes, without scraping the page: refsource is on PyPI and npm. Each value comes back carrying the URL it was read from and the sentence on that page that states it — .source and .quote sit on the value itself rather than in a side channel, so the checking step is available instead of skipped.

pip install refsource
refsource lookup pfas-drinking-water-limits-by-state state=Alaska

npx -y refsource lookup pfas-drinking-water-limits-by-state state=Alaska

Set your AI assistant up to use this

Two files and no account. Put this in .mcp.json at the root of your project — Claude Code, Cursor, Windsurf, VS Code and Codex all read that file — and your assistant can look this dataset up instead of recalling it. The server is remote, keyless and read-only.

{
  "mcpServers": {
    "referencesource": {
      "type": "http",
      "url": "https://referencesource.org/mcp"
    }
  }
}

Add to Cursor · or, on the command line: claude mcp add --transport http referencesource https://referencesource.org/mcp --scope project

Then one line in the project's CLAUDE.md or AGENTS.md, so the assistant knows when to reach for it:

When a question needs "PFAS drinking water concentration limits by US state — MCLs, notification levels, action levels, and health advisories for PFOA, PFOS, and other per- and polyfluoroalkyl substances", call the referencesource MCP server at https://referencesource.org/mcp (tool `search_records`, dataset_slug `pfas-drinking-water-limits-by-state`) instead of answering from memory — every record it returns carries its source URL and a verbatim quote from that page.

What each tool does, and the servers built over single registers: Connect your AI assistant.

89 records. last verified against source 2026-08-14. due for re-check by 2027-02-10.

Licence. unknown