We read 18 results from Commonwealth Utilities Corp (Saipan)’s 2025 water quality report. No results over a legal limit; 8 above a health goal or guideline.
Serves about 48,524 people · Water system ID MP0000001 · Read the district’s 2025 report (opens in a new tab)
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Results from the 2025 report
Each number is copied from the district’s report and links to the page it’s printed on. Where the report lists several plants, wells or purchased water, the highest is shown.
| Contaminant | Result | Health goal | Legal limit | What it means |
|---|---|---|---|---|
| Chlorideaverage · range 25 to 3,730 · Wells · 2025 report, page 4 | 683 ppm | — | 250 ppm guideline | Above the guideline2.7x the guideline (taste, odor or stains; not a health limit) |
| Gross alpha (radioactivity)highest measured · range ND to 2.9 · listed as a violation in the report · Wells · 2025 report, page 4 | 2.9 pCi/L | 0 pCi/L | 15 pCi/L | Above the health goalThe health goal is zero |
| Lead90th percentile of homes tested, 0 over the action level · listed as a violation in the report · sampled 2023 · Customer taps · 2025 report, page 4 | 2.5 ppb | 0.2 ppb | 15 ppb (action level) | Above the health goal13x the health goal |
| PFOA (a PFAS)highest measured · range ND to 5.7 · listed as a violation in the report · Wells · 2025 report, page 4 | 5.7 ppt | 0.007 ppt | 4 ppt from 2029 | Above the federal limit that takes effect in 20291.4x the 4 ppt federal limit that takes effect in 2029Not a violation yet: EPA's 4 ppt limit is final, but water systems don't have to meet it until 2029. |
| PFOS (a PFAS)highest measured · range ND to 60 · listed as a violation in the report · Wells · 2025 report, page 4 | 60 ppt | 1 ppt | 4 ppt from 2029 | Above the federal limit that takes effect in 202915x the 4 ppt federal limit that takes effect in 2029Not a violation yet: EPA's 4 ppt limit is final, but water systems don't have to meet it until 2029. |
| Radium (combined 226 + 228)highest measured · range ND to 1.3 · listed as a violation in the report · Wells · 2025 report, page 4 | 1.3 pCi/L | 0 pCi/L | 5 pCi/L | Above the health goalThe health goal is zero |
| Total dissolved solidsaverage · range 319 to 6,980 · Wells · 2025 report, page 4 | 1,559 ppm | — | 500 ppm guideline | Above the guideline3.1x the guideline (taste, odor or stains; not a health limit) |
| Uraniumhighest measured · range 0.5 to 2.2 · listed as a violation in the report · Wells · 2025 report, page 4 | 2.2 ppb | 0.6 ppb | 30 ppb | Above the health goal3.7x the health goal |
| Bariumhighest measured · range 0.0022 to 0.0093 · listed as a violation in the report · Wells · 2025 report, page 4 | 0.0093 ppm | 2 ppm | 2 ppm | Below the health goal |
| Chlorinehighest running annual average · range 0.02 to 5.4 · listed as a violation in the report · Distribution system · 2025 report, page 4 | 1.5 ppm | None set | 4 ppm | Below the legal limit |
| Chromium (total)highest measured · range ND to 4.2 · listed as a violation in the report · Wells · 2025 report, page 4 | 4.2 ppb | None set | 100 ppb | Below the legal limit |
| Copper90th percentile of homes tested, 0 over the action level · listed as a violation in the report · sampled 2023 · Customer taps · 2025 report, page 4 | 0.06 ppm | 0.3 ppm | 1.3 ppm (action level) | Below the health goal |
| Disinfection byproducts (HAA5)highest running annual average · range ND to 2.3 · listed as a violation in the report · Distribution system · 2025 report, page 4 | 1.1 ppb | None set | 60 ppb | Below the legal limit |
| Disinfection byproducts (TTHM)highest running annual average · range ND to 11 · listed as a violation in the report · Distribution system · 2025 report, page 4 | 8.8 ppb | None set | 80 ppb | Below the legal limit |
| Fluoridehighest measured · range ND to 0.16 · listed as a violation in the report · Wells · 2025 report, page 4 | 0.16 ppm | 1 ppm | 4 ppm | Below the health goal |
| Nitrate (as N)highest measured · range 1.3 to 5.8 · listed as a violation in the report · Wells · 2025 report, page 4 | 5.8 ppm | 10 ppm | 10 ppm | Below the health goal |
| Sulfateaverage · range 5.2 to 450 · Wells · 2025 report, page 4 | 96 ppm | — | 250 ppm guideline | Within the guideline |
| Sodiumhighest measured · range 15 to 1,700 · listed as a violation in the report · Wells · 2025 report, page 4 | 1,700 ppm | None set | None | No health limit |
Utility results describe the whole system, measured where water enters the pipes, not your tap. Your home’s plumbing can add lead or copper. 2 numbers we weren’t sure about are held back until a person checks.
EPA testing for PFAS and lithium
EPA’s own nationwide testing (UCMR 5) found these in Commonwealth Utilities Corp (Saipan)’s water between Oct 2023 and Sep 2024. These are EPA lab results, separate from the district’s report. Anything not listed was not detected.
- PFOS32.1 pptFound in 7 of 27 samples · highest resultAbove the federal limit that takes effect in 2029 (4 ppt)
- PFHxS19.6 pptFound in 4 of 27 samples · highest resultNo federal limit in force for this one
- PFBS14.6 pptFound in 4 of 27 samples · highest resultNo federal limit in force for this one
- Lithium58.4 ppbFound in 14 of 30 samples · highest resultAbove EPA’s health reference level of 10 ppb (a guide, not a legal limit)
Source: EPA UCMR 5 occurrence data. The highest single result is shown; one high sample doesn’t mean every glass is that high.
What you can do
Nothing here is an emergency notice: if the district has a violation, it must tell customers directly. If you’d like to lower these at your tap, these are the treatments that remove them, and the catalog shows the models certified for each. Ranking is by certified removal; commissions never change the order.
Salty taste / high TDS
Found: Chloride, Total dissolved solids
What removes it: Reverse osmosis.
Radium and uranium
Found: Gross alpha (radioactivity), Radium (combined 226 + 228), Uranium
What removes it: Reverse osmosis.
Lead
Found: Lead
What removes it: Certified carbon block or RO.
PFAS ("forever chemicals")
Found: PFOA (a PFAS), PFOS (a PFAS), PFOS (EPA testing)
What removes it: Reverse osmosis.
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