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Yerkes Water Association

What EPA’s and Pennsylvania’s records show in this utility’s water: PFAS; nitrate, arsenic and other regulated chemicals; lead and copper; and violations since 2016, with the certification that handles each result.

Serves
165 people
Connections
59
Water source
Groundwater
Based in
Collegeville, PA
County
Montgomery
Owner
Private
The ZIP code it serves

19426

The short answer

1 result is above EPA’s legal limit, 2 more are above EPA’s new limit, which takes effect in 2029, and 2 more are above the health goal. The worst: Lead, above the action level. 8 health-based violations since 2016.

What handles it

What was found

PFAS: Pennsylvania’s own results under its PFAS rule, entry point samples taken from Jan. 27, 2025 to Aug. 17, 2026.

Lead and copper: EPA SDWIS monitoring periods ending 1995 to 2010.

Arsenic, uranium, total trihalomethanes (TTHM), nitrate, haloacetic acids (HAA5), chromium (total) and fluoride: Pennsylvania’s own results, samples taken from Oct. 6, 2020 to Oct. 6, 2025, with EPA’s 2012 to 2019 file for earlier years.

PFAS: PFOA, PFOS, PFHxS, PFNA and PFBS were found, of the six PFAS in EPA’s 2024 drinking water rule; their results are below. Four other PFAS with no federal limit were found, the highest PFPeA at 7.5 ppt: see them below.

EPA’s 2024 PFAS rule, compound by compound

PFASEPA’s limitResult
PFOA4.0 pptAbove EPA’s new limit (2029)10.8 ppt highest, found in 8 of 12 samples. Details
PFOS4.0 pptAbove EPA’s new limit (2029)9.2 ppt highest, found in 8 of 12 samples. Details
PFHxS10 pptBelow EPA’s limits2.5 ppt highest, found in 5 of 12 samples. Details
PFNA10 pptBelow EPA’s limits1.9 ppt highest, found in 3 of 12 samples. Details
HFPO-DA (GenX)10 pptNot foundNot found in any of 12 samples
PFBSIndex onlyBelow EPA’s limits9.6 ppt highest, found in 12 of 12 samples. Details
Results from Pennsylvania’s own PFAS monitoring, samples where water enters the pipes; each compound’s card has its four-quarter averages, the way limits are judged. The limits are EPA’s 2024 rule, with compliance due from 2029; EPA has since proposed changes to some of them, explained on each compound’s page. Pennsylvania’s own limits for PFOA and PFOS are in force now. PFBS has no limit of its own and counts only toward EPA’s Hazard Index, which TapBuff works out only from UCMR 5’s averages, so it isn’t given here.

About PFAS certifications

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.

Above the legal limit1

Lead

Comes from pipes, often your own

Above the action level

160ppb

90th percentile, 2010

In the latest period, 9 in 10 homes sampled were at or below 160 ppb, above EPA’s action level of 15 ppb. The action level drops to 10 ppb on Nov. 1, 2027, and this result is at or above that. EPA’s health goal for lead is zero.

What handles it

Above EPA’s new limit, which takes effect in 20292

PFOA

Comes from the source

Above EPA’s new limit (2029)

10.8ppt

Highest sample, Jan. 27, 2025; found in 8 of 12

2026 average: 7.5 ppt

The highest sample was 10.8 ppt, about 2.7 times EPA’s new limit of 4.0 ppt, which takes effect in 2029. EPA’s health goal is zero. Compliance will be judged on a running annual average, not one sample. Averaged over four quarters at one entry point, the way both Pennsylvania’s limit and EPA’s are judged, the highest was 8.0 ppt, for the year to Dec. 31, 2025: below Pennsylvania’s limit of 14 ppt and above EPA’s new limit of 4.0 ppt. In 2026, the latest year on file, its four samples averaged 7.5 ppt.

What handles it

PFOS

Comes from the source

Above EPA’s new limit (2029)

9.2ppt

Highest sample, Aug. 17, 2026; found in 8 of 12

2026 average: 8.2 ppt

The highest sample was 9.2 ppt, about 2.3 times EPA’s new limit of 4.0 ppt, which takes effect in 2029. EPA’s health goal is zero. Compliance will be judged on a running annual average, not one sample. Averaged over four quarters at one entry point, the way both Pennsylvania’s limit and EPA’s are judged, the highest was 8.0 ppt, for the year to Sept. 30, 2026: below Pennsylvania’s limit of 18 ppt and above EPA’s new limit of 4.0 ppt. In 2026, the latest year on file, its four samples averaged 8.2 ppt.

What handles it

Above the health goal2

Arsenic

Comes from the source

Above the health goal

2.0ppb

Highest yearly average, 2021 to 2024

2024 average: 1.5 ppb

Averaged by year, the highest was 2.0 ppb, in 2021: below EPA’s legal limit of 10 ppb, but above its health goal of zero. Its highest single sample was 3.0 ppb. In 2024, the latest year on file, its two samples averaged 1.5 ppb. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 2.5 ppb, in 2018.

What handles it

  • NSF/ANSI 58 look for “Arsenic (Pentavalent)<=50 ppb Reduction”
  • NSF/ANSI 53 look for “Arsenic (Pentavalent)<=50 ppb Reduction”

Uranium

Comes from the source

Above the health goal

3.3ppb

Highest yearly average, 2025

Averaged by year, the highest was 3.3 ppb, in 2025: below EPA’s legal limit of 30 ppb, but above its health goal of zero. Its highest single sample was 3.5 ppb. That is the only year on file. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 3.8 ppb, in 2013.

What handles it

Below EPA’s limits6

Total trihalomethanes (TTHM)

Forms or is added in treatment

Below EPA’s limits

47.2ppb

Highest yearly average, 2021 to 2024

Averaged by year, the highest was 47.2 ppb, in 2024, below EPA’s legal limit of 80 ppb. That was also the latest year on file. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 3.2 ppb, in 2018.

What handles it

  • NSF/ANSI 53 look for “Trihalomethanes (TTHM) Reduction”
  • NSF/ANSI 58 look for “Trihalomethanes (TTHM) Reduction”

Nitrate

Comes from the source

Below EPA’s limits

3.2ppm

Highest sample; found in 11 of 12

2025 average: 2.5 ppm

The highest sample, in 2023, was 3.2 ppm, below EPA’s legal limit of 10 ppm. In 2025, the latest year on file, its two samples averaged 2.5 ppm. Earlier, from 2012 to 2019, EPA’s file shows a highest sample of 3.3 ppm, in 2018.

What handles it

  • NSF/ANSI 58 look for “Nitrate/Nitrite Reduction”
  • NSF/ANSI 53 look for “Nitrate/Nitrite (30 ppm challenge)”

PFHxS

Comes from the source

Below EPA’s limits

2.5ppt

Highest sample, Aug. 17, 2026; found in 5 of 12

2026 average: 1.1 ppt

The highest sample was 2.5 ppt, below EPA’s new limit of 10 ppt, which takes effect in 2029. Averaged over four quarters at one entry point, the way EPA’s limit is judged, the highest was 1.4 ppt, for the year to Dec. 31, 2025: below EPA’s new limit of 10 ppt. In 2026, the latest year on file, its four samples averaged 1.1 ppt.

What handles it

PFNA

Comes from the source

Below EPA’s limits

1.9ppt

Highest sample, Jan. 27, 2025; found in 3 of 12

2026 average: 0.45 ppt

The highest sample was 1.9 ppt, below EPA’s new limit of 10 ppt, which takes effect in 2029. Averaged over four quarters at one entry point, the way EPA’s limit is judged, the highest was 0.95 ppt, for the year to Dec. 31, 2025: below EPA’s new limit of 10 ppt. In 2026, the latest year on file, its four samples averaged 0.45 ppt.

What handles it

Haloacetic acids (HAA5)

Forms or is added in treatment

Below EPA’s limits

4.2ppb

Highest yearly average, 2021 to 2024

Averaged by year, the highest was 4.2 ppb, in 2024, below EPA’s legal limit of 60 ppb. That was also the latest year on file.

What handles it

No certification claim covers this compound yet.

PFBS

Comes from the source

Below EPA’s limits

9.6ppt

Highest sample, Aug. 17, 2026; found in 12 of 12

2026 average: 7.5 ppt

The highest sample was 9.6 ppt, below EPA’s hazard index benchmark of 2,000 ppt. PFBS has no legal limit or health goal of its own. In 2026, the latest year on file, its four samples averaged 7.5 ppt.

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
PFPeA7.5 ppt1 of 1None covers it
PFHxA7.4 ppt1 of 1None covers it
PFBA6.6 ppt1 of 1None covers it
PFHpA4.4 ppt1 of 1NSF/ANSI 53: Total PFAS Reduction
18 compounds tested and not foundBelow the reporting level in every sample. Not found is not the same as zero.

From routine monitoring

  • Chromium (total)
  • Fluoride

PFAS, from Pennsylvania’s own monitoring

  • 11Cl-PF3OUdS
  • 4:2 FTS
  • 6:2 FTS
  • 8:2 FTS
  • 9Cl-PF3ONS
  • ADONA
  • HFPO-DA (GenX)
  • NFDHA
  • PFDA
  • PFDoA
  • PFEESA
  • PFHpS
  • PFMBA
  • PFMPA
  • PFPeS
  • PFUnA

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: Lead Reduction, PFOA Reduction, PFOS Reduction, Arsenic (Pentavalent)<=50 ppb Reduction

    For: Lead, PFOA, PFOS, Arsenic

    Other certifiers’ wording: Total PFAS Reduction; Perfluorooctanoic Acid (PFOA); Perfluorooctane Sulfonate (PFOS); Arsenic (III) (50 ppb influent level)

  • NSF/ANSI 58

    Claims: Lead Reduction, Perfluorooctanoic Acid (PFOA), Perfluorooctane Sulfonate (PFOS), Arsenic (Pentavalent)<=50 ppb Reduction, Uranium

    For: Lead, PFOA, PFOS, Arsenic, Uranium

    Other certifiers’ wording: Arsenic (Pentavalent)<=300 ppb Reduction; Arsenic (V) (300 ppb influent level)

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.

Filters with those claims on a certifier’s listing

Disclosure: 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

Compare five-year costs

The best water filters for lead, ranked

The best water filters for PFAS, ranked

The best reverse osmosis systems, ranked

Violations since 2016

Contaminant or ruleTypePeriodMeasuredStatus
Groundwater RuleRequired treatment for surface water or groundwater was not met.EPA: Treatment Technique (SWTR and GWR)Aug. 1, 2025 to Aug. 31, 2025—Resolved
Groundwater RuleRequired treatment for surface water or groundwater was not met.EPA: Treatment Technique (SWTR and GWR)Sept. 1, 2019 to Sept. 30, 2019—Resolved
Groundwater RuleRequired treatment for surface water or groundwater was not met.EPA: Treatment Technique (SWTR and GWR)March 1, 2019 to March 31, 2019—Resolved
Groundwater RuleRequired treatment for surface water or groundwater was not met.EPA: Treatment Technique (SWTR and GWR)Jan. 1, 2019 to Jan. 31, 2019—Resolved
Groundwater RuleRequired treatment for surface water or groundwater was not met.EPA: Treatment Technique (SWTR and GWR)July 1, 2018 to July 31, 2018—Resolved
Groundwater RuleRequired treatment for surface water or groundwater was not met.EPA: Treatment Technique (SWTR and GWR)June 1, 2018 to June 30, 2018—Resolved
Groundwater RuleRequired treatment for surface water or groundwater was not met.EPA: Treatment Technique (SWTR and GWR)Feb. 1, 2017 to Feb. 28, 2017—Resolved
Groundwater RuleRequired treatment for surface water or groundwater was not met.EPA: Treatment Technique (SWTR and GWR)Sept. 1, 2016 to Sept. 30, 2016—Resolved
Health-based violations only. Resolved and archived mean the utility returned to compliance or the state closed the record. 21 monitoring or reporting violations not shown.

What this report can’t tell you

  • Everything else. Arsenic, uranium, total trihalomethanes (TTHM), nitrate, haloacetic acids (HAA5), chromium (total) and fluoride results here are Pennsylvania’s own from 2020 on, with EPA’s national file for 2012 to 2019. Yerkes Water Association’s own annual report, which it must send you every year, has the contaminants this page does not show.

  • 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.

  • What it means for your health. This page reports what the records show and EPA’s limits and goals; it is not medical advice. If you are worried about a health effect, talk to a doctor or your local health department.

  • Anything after the latest data. SDWIS data is from 2026 Q3; UCMR 5 didn’t sample this utility; Pennsylvania’s results run from Oct. 6, 2020 to Oct. 6, 2025; Pennsylvania’s PFAS results run from Jan. 27, 2025 to Aug. 17, 2026.

Testing your own tap

Yerkes Water Association’s results are for the water it sends out. What your own service line, solder and fixtures add shows up only in a test of your tap, by a lab Pennsylvania certifies.

The 3 labs Pennsylvania certifies closest to the area Yerkes Water Association serves, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.

  • Analytical Laboratories, Inc

    Telford, PA · about 10 miles

    Certified for bacteria, nitrate

    (215) 723-6466

  • Aqua Pennsylvania, Inc.

    Bryn Mawr, PA · about 13 miles

    Certified for bacteria, nitrate, lead and copper, metals, minerals and other inorganics, organic chemicals, disinfection byproducts, PFAS, radioactivity

    (610) 525-1400

  • Eurofins Philadelphia - Horsham

    Horsham, PA · about 15 miles

    Certified for bacteria

    (215) 355-3900

Penn State Agricultural Analytical Services Laboratory: Drinking water test kits from many county Extension offices, mailed back to the lab overnight with payment. Packages cover bacteria and basic chemistry, with add-ons for nitrate, metals, lead, and mining or gas drilling concerns. The standard package of bacteria, pH and total dissolved solids is $60, or $70 with nitrate; bacteria alone is $40, nitrate $15 and lead $25. Drinking Water Testing, Penn State Agricultural Analytical Services Lab.

All 108 certified labs for Pennsylvania

Sources

PWSID PA1460064. Rebuilt from EPA data on Oct. 18, 2026.

Towns it serves

Also in Montgomery County

All Pennsylvania utilities

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