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Commonwealth Utilities Corp (Saipan) water quality report, rewritten

Serves
48,524
Connections
11,317
Water source
Groundwater
Based in
Saipan, MP
Owner
State government
The ZIP code it serves

96950

PWSID MP0000001 · EPA data

Read this first

  • PFOS (above the health goal) was found in seven of 27 samples, highest 32.1 ppt. Above the 4.0 ppt legal limit in at least one sample. Compliance is judged on a running annual average, not one sample.
  • PFHxS (above the health goal) was found in four of 27 samples, highest 19.6 ppt. Above the 10 ppt legal limit in at least one sample. Compliance is judged on a running annual average, not one sample.
  • Lithium (above EPA’s health benchmark) was found in 14 of 30 samples, highest 58.4 ppb. Above EPA’s health reference level of 10 ppb, a screening level rather than an enforceable limit.
  • Lead (above the health goal) In the latest period, 9 in 10 homes sampled were at or below 2.5 ppb, below the 15 ppb action level. The action level drops to 10 ppb on Nov. 1, 2027. EPA’s health goal for lead is zero.

14 health-based violations since 2016. Details are below.

What handles it

What was found

Highlighted: above the health goal, or EPA’s health benchmark where there is no goal. Circled: above the legal limit in at least one sample, or the action level. Every scale puts that line at its middle.

PFAS and lithium: EPA UCMR 5, samples taken from Oct. 18, 2023 to Sept. 9, 2024. Each blue tick on a scale is one sample where it was found.

Lead and copper: EPA SDWIS monitoring periods ending 2019 to 2025. The pointer marks the latest period; each blue tick is an earlier one.

NSF’s PFAS claims are tested to below 20 ppt. EPA’s limit is 4.0 ppt, and EPA says no certification yet shows a filter reaching its levels.

PFOS (above the health goal)

Comes from the source

32.1 (above the legal limit in at least one sample)ppt

Highest of 27 samples; found in seven

Above the 4.0 ppt legal limit in at least one sample. Compliance is judged on a running annual average, not one sample.

What handles it

PFHxS (above the health goal)

Comes from the source

19.6 (above the legal limit in at least one sample)ppt

Highest of 27 samples; found in four

Above the 10 ppt legal limit in at least one sample. Compliance is judged on a running annual average, not one sample.

What handles it

58.4ppb

Highest of 30 samples; found in 14

Above EPA’s health reference level of 10 ppb, a screening level rather than an enforceable limit.

What handles it

No certification claim covers this compound yet.

Lead (above the health goal)

Comes from pipes, often your own

2.5ppb

90th percentile, 2023 to 2025

In the latest period, 9 in 10 homes sampled were at or below 2.5 ppb, below the 15 ppb action level. The action level drops to 10 ppb on Nov. 1, 2027. EPA’s health goal for lead is zero.

What handles it

PFBS

Comes from the source

14.6ppt

Highest of 27 samples; found in four

Below EPA’s hazard index benchmark of 2,000 ppt. PFBS has no legal limit or health goal of its own.

What handles it

Also found, with no federal limit

EPA measured these PFAS to learn how often they occur. None has a legal limit or a health goal yet.

CompoundHighest sampleFound inCertification claim
PFPeA134 ppt6 of 27None covers it
PFHxA122 ppt5 of 27None covers it
PFBA32.3 ppt1 of 27None covers it
PFHpA22.9 ppt4 of 27NSF/ANSI 53: Total PFAS Reduction
6:2 FTS12.5 ppt2 of 27None covers it
PFPeS5.4 ppt1 of 27None covers it

Tested and not found

Below EPA’s minimum reporting level in every sample taken from Oct. 18, 2023 to Sept. 9, 2024. Not found means not measured above that level, which is not the same as zero.

All 20 compounds tested and not found
  • 11Cl-PF3OUdS
  • 4:2 FTS
  • 8:2 FTS
  • 9Cl-PF3ONS
  • ADONA
  • HFPO-DA (GenX)
  • NEtFOSAA
  • NFDHA
  • NMeFOSAA
  • PFDA
  • PFDoA
  • PFEESA
  • PFHpS
  • PFMBA
  • PFMPA
  • PFNA
  • PFOA
  • PFTA
  • PFTrDA
  • PFUnA

Violations since 2016

Contaminant or ruleTypePeriodMeasuredStatus
Revised Total Coliform RuleE. coli was confirmed in the water system.EPA: Maximum Contaminant Level Violation, E. coli (RTCR)Nov. 1, 2023 to Nov. 30, 2023—Resolved
Revised Total Coliform RuleColiform results required a check of the system, and the check or its fixes were not done on time.EPA: Treatment Technique, Level 1 Assessment (RTCR)Oct. 1, 2023—Resolved
Groundwater RuleA significant problem found in a state inspection was not fixed on time.EPA: Failure To Address DeficiencyDec. 1, 2021—Resolved
Groundwater RuleA significant problem found in a state inspection was not fixed on time.EPA: Failure To Address DeficiencySept. 1, 2021—Resolved
Groundwater RuleA significant problem found in a state inspection was not fixed on time.EPA: Failure To Address DeficiencyApril 1, 2021—Resolved
Groundwater RuleA significant problem found in a state inspection was not fixed on time.EPA: Failure To Address DeficiencyApril 1, 2021—Resolved
Groundwater RuleA significant problem found in a state inspection was not fixed on time.EPA: Failure To Address DeficiencyOct. 30, 2019—Resolved
Groundwater RuleA significant problem found in a state inspection was not fixed on time.EPA: Failure To Address DeficiencyOct. 30, 2019—Resolved
Revised Total Coliform RuleE. coli was confirmed in the water system.EPA: Maximum Contaminant Level Violation, E. coli (RTCR)Oct. 1, 2019 to Oct. 31, 2019—Resolved
Groundwater RuleA significant problem found in a state inspection was not fixed on time.EPA: Failure To Address DeficiencyMarch 31, 2019—Resolved
Groundwater RuleA significant problem found in a state inspection was not fixed on time.EPA: Failure To Address DeficiencyMarch 31, 2019—Resolved
Groundwater RuleA significant problem found in a state inspection was not fixed on time.EPA: Failure To Address DeficiencyMarch 31, 2019—Resolved
Groundwater RuleA significant problem found in a state inspection was not fixed on time.EPA: Failure To Address DeficiencyMarch 31, 2019—Resolved
Coliform (TCR)Too many samples in a month tested positive for coliform bacteria.EPA: Maximum Contaminant Level Violation, Monthly (TCR)March 1, 2016 to March 31, 2016—Resolved
Health-based violations only. Resolved and archived mean the utility returned to compliance or the state closed the record.

What handles it

A certification covers specific claims, not a whole standard. Look for these claims on the certifier’s listing, not the box. Wording varies a little: NSF writes “Lead Reduction,” WQA just “Lead.”

  • NSF/ANSI 53

    Claims: PFOS Reduction, Total PFAS Reduction, Lead Reduction

    Other certifiers’ wording: Perfluorooctane Sulfonate (PFOS); Perfluorohexane Sulfonic Acid (PFHxS)

    For: PFOS, PFHxS, Lead

  • NSF/ANSI 58

    Claims: Perfluorooctane Sulfonate (PFOS), Lead Reduction

    For: PFOS, Lead

At the tap, or for the whole house?

Lead and copper usually come from pipes and fixtures inside or near your home. A whole-house system sits where water enters, so it cannot catch what your own plumbing adds after it. For those, the filter that counts is the one at the tap. How whole-house systems compare.

Compare five-year costs

Filters with those claims on a certifier’s listing

TapBuff earns a commission if you buy through some links on this page. It does not change which standard or filter we name. As an Amazon Associate, TapBuff earns from qualifying purchases. How TapBuff makes money

What this report cannot tell you

  • Levels of everything else. Federal bulk data carries results for PFAS, lithium, lead and copper, and violations for the rest. Nitrate, arsenic, disinfection byproducts and other levels are in Commonwealth Utilities Corp (Saipan)’s own annual report, which it must send you every year.
  • Your own plumbing. Lead results are the 90th percentile across homes the utility samples. Your home’s service line, solder and fixtures decide yours. A certified lab test is the only way to know.
  • Anything after the latest data. SDWIS data is from 2026 Q2; UCMR 5 samples are from Oct. 18, 2023 to Sept. 9, 2024.

Other Northern Mariana Islands utilities

    All Northern Mariana Islands utilities

    Sources

    What to do next

    • Read up on the 4 marked results

      What each one does to health, where it comes from, and the certification claim that addresses it.

      Start with PFOS

    • Get the utility’s own report

      Commonwealth Utilities Corp (Saipan) must send you a water quality report every year. It lists nitrate, arsenic and byproduct levels this page cannot.

      How to read it

    • Test your own tap for lead

      Your service line, solder and fixtures decide the lead at your faucet, not the utility’s average.

      Lead in your water: what to do

    • Compare certified filters

      What the filters certified for these results cost over five years, cartridges included.

      Compare five-year costs