Is there PFAS in Commonwealth Utilities Corp (Saipan) water?

Yes. EPA's final UCMR 5 results show Commonwealth Utilities Corp (Saipan) averaged 32.1 ppt of PFOS at its worst sampling point, 8.0 times the EPA limit of 4 ppt.

Commonwealth Utilities Corp (Saipan) is a public water system drawing on groundwater, based in Saipan, Northern Mariana Islands, serving about 48,524 people. Under EPA's Fifth Unregulated Contaminant Monitoring Rule it was tested for 29 PFAS and lithium 27 times across 15 sampling points between Oct 2023 and Sep 2024.

Every PFAS detected

Not detected: PFHpS, 4:2 FTS, 8:2 FTS, PFMPA, PFMBA, PFEESA, PFTrDA, PFTA, NMeFOSAA, NFDHA, PFDoA, NEtFOSAA, PFNA, PFDA, PFUnA, 11Cl-PF3OUdS, 9Cl-PF3ONS, ADONA, HFPO-DA, PFOA.

Lithium, tested in the same program: highest 58.4 ppb, detected in 14 of 30 samples. EPA's health-based screening level is 10 ppb.

What the EPA limits mean here

In April 2024 EPA set enforceable limits of 4 ppt for PFOA and PFOS, 10 ppt each for PFHxS, PFNA and GenX, and a hazard index of 1 for mixtures. Utilities were given until 2029 to comply. In May 2026 EPA proposed keeping only the PFOA and PFOS limits and moving that deadline to 2031. Until that proposal is final, the 2024 limits stand.

Compliance is judged on a running annual average at each entry point, so we show the average at this system's worst sampling point next to its single highest result. UCMR 5 results do not by themselves put a utility in or out of compliance.

What you can do at home

Two routes work for PFAS. For drinking and cooking water only, a reverse osmosis system certified to NSF/ANSI 58 with a PFOA/PFOS reduction claim is the cheapest proven option. To treat every tap and shower, a whole-house carbon system with enough contact time works, but check that the maker has PFAS test data, not just a marketing claim. See the best filters for PFAS and how PFAS removal works.

Other systems in Northern Mariana Islands

All 2 tested systems in Northern Mariana Islands

ZIP codes served

96950

As reported by the utility to EPA. Neighbouring ZIPs are often split between systems; your water bill names yours.

Cite this page

Well & Tap. "PFAS in Commonwealth Utilities Corp (Saipan) water: EPA UCMR 5 results." Data: U.S. EPA Fifth Unregulated Contaminant Monitoring Rule, final release August 2026, PWSID MP0000001. https://wellandtap.com/pfas/northern-mariana-islands/commonwealth-utilities-corp-saipan/

About this data

Source: U.S. EPA, UCMR 5 occurrence data, final release August 2026 (PWSID MP0000001). Population: EPA SDWIS. Averages count results below the reporting level as zero, the same convention EPA uses for running annual averages. Full method.