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St Peters PWSWater quality report

Standards for what was found here

5358
Serves
52,575
Connections
19,083
Water source
Surface water bought from another system
Based in
St. Peters, MO
County
St. Charles
Owner
Local government
The 6 ZIP codes it serves

63301, 63303, 63304, 63366, 63368, 63376

PWSID MO6010719 · EPA data

Read this first

  • PFOA was found in two of 6 samples, highest 4.9 ppt. Above the 4.0 ppt legal limit in at least one sample. Compliance is judged on a running annual average, not one sample.
  • Lithium was found in six of 6 samples, highest 53.1 ppb. Above EPA’s health reference level of 10 ppb, a screening level rather than an enforceable limit.

No health-based violations on file since 2016. EPA lists 1 monitoring or reporting violation, which are paperwork and testing lapses rather than water quality findings.

What handles it

What was found, stop by stop

  • Below the health goal
  • Above the health goal
  • Above the legal limit
  • No federal data

  1. At the source

    EPA UCMR 5 sampled this utility for 29 PFAS and lithium from March 12, 2024 to Dec. 17, 2024. Each tick under a result’s line is one sample where it was found, dated when you point at it.

    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.

  2. PFOA

    Above the legal limit

    4.9ppt

    Highest of 6 samples; found in two

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

    • NSF/ANSI 53 · Look for: PFOA ReductionSame claim, other certifiers’ wording: Total PFAS Reduction; Perfluorooctanoic Acid (PFOA)

    • NSF/ANSI 58 · Look for: Perfluorooctanoic Acid (PFOA)

  3. Lithium

    Above EPA’s health benchmark

    53.1ppb

    Highest of 6 samples; found in six

    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.

  4. 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
    PFBA10.6 ppt2 of 6None covers it
    PFPeA5.9 ppt2 of 6None covers it
    PFHxA5.9 ppt2 of 6None covers it

  5. In treatment

    No federal results for this stop. Disinfection byproduct, chlorine and fluoride levels are in St Peters PWS’s own annual report, which it must send you every year.

  6. In the pipes

    No lead and copper results on file with EPA for this utility.

  7. At your tap

    The last stretch is your own plumbing. A certified lab test is the only way to know what reaches your glass. Lead in your water: what to do

Tested and not found

Below EPA’s minimum reporting level in every sample taken from March 12, 2024 to Dec. 17, 2024. Not found means not measured above that level, which is not the same as zero.

All 26 compounds tested and not found
  • 11Cl-PF3OUdS
  • 4:2 FTS
  • 6:2 FTS
  • 8:2 FTS
  • 9Cl-PF3ONS
  • ADONA
  • HFPO-DA (GenX)
  • Lead
  • NEtFOSAA
  • NFDHA
  • NMeFOSAA
  • PFBS
  • PFDA
  • PFDoA
  • PFEESA
  • PFHpA
  • PFHpS
  • PFHxS
  • PFMBA
  • PFMPA
  • PFNA
  • PFOS
  • PFPeS
  • PFTA
  • PFTrDA
  • PFUnA

Violations since 2016

No health-based violations on file with EPA since 2016. There is 1 monitoring or reporting violation: a sample missed, late or not reported.

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.”

At the tap, or for the whole house?

These come with the water itself, so a whole-house system certified for the same claims treats every tap and shower. A filter at the tap treats drinking water for much less. 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 St Peters PWS’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 March 12, 2024 to Dec. 17, 2024.

Other Missouri utilities

All Missouri utilities

Sources

What to do next

  1. Start with PFOA

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

  2. Read the utility’s own report

    St Peters PWS must send you a water quality report every year. It lists nitrate, arsenic and byproduct levels this page cannot.

  3. Test your own tap for lead

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

  4. Compare five-year costs

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