Cornerstone Living
What EPA’s and Pennsylvania’s records show in this utility’s water: PFAS; nitrate, arsenic and other regulated chemicals; and violations since 2016, with the certification that handles each result.
- Serves
- 44 people
- Connections
- 1
- Water source
- Groundwater
- Based in
- New Tripoli, PA
- County
- Lehigh
- Owner
- Private
The short answer
2 results are above EPA’s new limit, which takes effect in 2029, and 1 more is above the health goal. The worst: PFOA, above EPA’s new limit (2029). 2 health-based violations since 2016.
What handles itWhat was found
PFAS: Pennsylvania’s own results under its PFAS rule, entry point samples taken from March 20, 2025 to Aug. 25, 2026.
Arsenic, nitrate, haloacetic acids (HAA5), total trihalomethanes (TTHM), chromium (total) and fluoride: Pennsylvania’s own results, samples taken from Feb. 24, 2020 to Aug. 25, 2026, with EPA’s 2012 to 2019 file for earlier years.
Uranium: EPA’s compliance monitoring file, samples taken from Sept. 28, 2017 to Oct. 26, 2017. Newer results are in the utility’s annual water quality report.
PFAS: PFOA, PFOS, PFHxS, PFNA and PFBS were found, of the six PFAS in EPA’s 2024 drinking water rule; their results are below. Two other PFAS with no federal limit were found, the highest PFHxA at 9.2 ppt: see them below.
EPA’s 2024 PFAS rule, compound by compound
| PFAS | EPA’s limit | Result |
|---|---|---|
| PFOA | 4.0 ppt | Above EPA’s new limit (2029)11 ppt highest, found in 6 of 7 samples. Details |
| PFOS | 4.0 ppt | Above EPA’s new limit (2029)8.6 ppt highest, found in 4 of 7 samples. Details |
| PFHxS | 10 ppt | Below EPA’s limits4.2 ppt highest, found in 3 of 7 samples. Details |
| PFNA | 10 ppt | Below EPA’s limits1.5 ppt highest, found in 1 of 7 samples. Details |
| HFPO-DA (GenX) | 10 ppt | Not foundNot found in any of 7 samples |
| PFBS | Index only | Below EPA’s limits7.3 ppt highest, found in 3 of 7 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 EPA’s new limit, which takes effect in 20292
PFOA
Comes from the source
11ppt
Highest sample, Dec. 18, 2025; found in 6 of 7
2026 average: 2.1 ppt
The highest sample was 11 ppt, about 2.8 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 4.3 ppt, for the year to Sept. 30, 2026: 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 three samples averaged 2.1 ppt.
What handles it
- NSF/ANSI 53 look for “PFOA Reduction”
- NSF/ANSI 58 look for “Perfluorooctanoic Acid (PFOA)”
PFOS
Comes from the source
8.6ppt
Highest sample, Dec. 18, 2025; found in 4 of 7
2026 average: 0.7 ppt
The highest sample was 8.6 ppt, about twice 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 3.5 ppt, for the year to March 31, 2026: below Pennsylvania’s limit of 18 ppt and below EPA’s new limit of 4.0 ppt. In 2026, the latest year on file, its three samples averaged 0.7 ppt.
What handles it
- NSF/ANSI 53 look for “PFOS Reduction”
- NSF/ANSI 58 look for “Perfluorooctane Sulfonate (PFOS)”
Above the health goal1
Arsenic
Comes from the source
2.0ppb
Highest yearly average, 2021 to 2024
2024: not found
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. In 2024, the latest year on file, it wasn’t found in its one sample.
What handles it
- NSF/ANSI 58 look for “Arsenic (Pentavalent)<=50 ppb Reduction”
- NSF/ANSI 53 look for “Arsenic (Pentavalent)<=50 ppb Reduction”
Below EPA’s limits6
Nitrate
Comes from the source
9.7ppm
Highest sample; found in 29 of 29
2026 average: 5.6 ppm
The highest sample, in 2022, was 9.7 ppm, below EPA’s legal limit of 10 ppm. In 2026, the latest year on file, its three samples averaged 5.6 ppm. Earlier, from 2012 to 2019, EPA’s file shows a highest sample of 6.7 ppm, in 2019.
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
4.2ppt
Highest sample, Dec. 18, 2025; found in 3 of 7
2026: not found
The highest sample was 4.2 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 1.6 ppt, for the year to Dec. 31, 2025: below EPA’s new limit of 10 ppt. In 2026, the latest year on file, it wasn’t found in any of its three samples.
What handles it
- NSF/ANSI 53 look for “Total PFAS Reduction”
PFNA
Comes from the source
1.5ppt
Highest sample, Dec. 18, 2025; found in 1 of 7
2026: not found
The highest sample was 1.5 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 0.38 ppt, for the year to Dec. 31, 2025: below EPA’s new limit of 10 ppt. In 2026, the latest year on file, it wasn’t found in any of its three samples.
What handles it
- NSF/ANSI 53 look for “Total PFAS Reduction”
Haloacetic acids (HAA5)
Forms or is added in treatment
8.8ppb
Highest yearly average, 2020 to 2025
2025: not found
Averaged by year, the highest was 8.8 ppb, in 2020, below EPA’s legal limit of 60 ppb. In 2025, the latest year on file, it wasn’t found in its one sample. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 1.6 ppb, in 2018.
What handles it
No certification claim covers this compound yet.
Total trihalomethanes (TTHM)
Forms or is added in treatment
2.5ppb
Highest yearly average, 2020 to 2025
2025: not found
Averaged by year, the highest was 2.5 ppb, in 2020, below EPA’s legal limit of 80 ppb. In 2025, the latest year on file, it wasn’t found in its one sample. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 1.1 ppb, in 2018.
What handles it
- NSF/ANSI 53 look for “Trihalomethanes (TTHM) Reduction”
- NSF/ANSI 58 look for “Trihalomethanes (TTHM) Reduction”
PFBS
Comes from the source
7.3ppt
Highest sample, Dec. 18, 2025; found in 3 of 7
2026: not found
The highest sample was 7.3 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, it wasn’t found in any of its three samples.
What handles it
- NSF/ANSI 53 look for “Total PFAS Reduction”
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.
| Compound | Highest sample | Found in | Certification claim |
|---|---|---|---|
| PFHxA | 9.2 ppt | 3 of 3 | None covers it |
| PFHpA | 5.8 ppt | 3 of 3 | NSF/ANSI 53: Total PFAS Reduction |
14 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
- Uranium
PFAS, from Pennsylvania’s own monitoring
- 11Cl-PF3OUdS
- 9Cl-PF3ONS
- ADONA
- HFPO-DA (GenX)
- NEtFOSAA
- NMeFOSAA
- PFDA
- PFDoA
- PFTA
- PFTrDA
- 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: PFOA Reduction, PFOS Reduction, Arsenic (Pentavalent)<=50 ppb Reduction
For: 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: Perfluorooctanoic Acid (PFOA), Perfluorooctane Sulfonate (PFOS), Arsenic (Pentavalent)<=50 ppb Reduction
For: PFOA, PFOS, Arsenic
Other certifiers’ wording: Arsenic (Pentavalent)<=300 ppb Reduction; Arsenic (V) (300 ppb influent level)
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.
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
Countertop reverse osmosis
- IAPMO listing:NSF/ANSI 42NSF/ANSI 53NSF/ANSI 58NSF/ANSI 401checked Oct. 4, 2026
Certified for: PFOA, PFOS, Arsenic
Aquasana SmartFlow Reverse Osmosis (AQ-SFRO2)
Under-sink reverse osmosis
- WQA listing:NSF/ANSI 42NSF/ANSI 53NSF/ANSI 58NSF/ANSI 401checked Oct. 9, 2026
Certified for: PFOA, PFOS, Arsenic
Brondell Capella RC250 Reverse Osmosis System
Under-sink reverse osmosis
- WQA listing:NSF/ANSI 42NSF/ANSI 53NSF/ANSI 58NSF/ANSI 401checked Oct. 9, 2026
Certified for: PFOA, PFOS, Arsenic
ZeroWater 10 Cup Pitcher (ZP-010)
Pitcher
- IAPMO listing:NSF/ANSI 42NSF/ANSI 53checked Oct. 4, 2026
Certified for: PFOA, PFOS
Aquasana Claryum Direct Connect (AQ-MF-1)
Under-sink carbon
- IAPMO listing:NSF/ANSI 42NSF/ANSI 53NSF/ANSI 401checked Oct. 16, 2026
Certified for: PFOA, PFOS
Violations since 2016
| Contaminant or rule | Type | Period | Measured | Status |
|---|---|---|---|---|
| Groundwater Rule | Required treatment for surface water or groundwater was not met.EPA: Treatment Technique (SWTR and GWR) | June 1, 2025 to June 30, 2025 | — | Resolved |
| Groundwater Rule | Required treatment for surface water or groundwater was not met.EPA: Treatment Technique (SWTR and GWR) | Dec. 1, 2022 to Dec. 31, 2022 | — | Resolved |
| Health-based violations only. Resolved and archived mean the utility returned to compliance or the state closed the record. 38 monitoring or reporting violations not shown. | ||||
What this report can’t tell you
Everything else. Arsenic, nitrate, haloacetic acids (HAA5), total trihalomethanes (TTHM), chromium (total) and fluoride results here are Pennsylvania’s own from 2020 on, with EPA’s national file for 2012 to 2019. Uranium comes from EPA’s file alone, which ends in 2019. Cornerstone Living’s own annual report, which it must send you every year, has newer results for those and 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 Feb. 24, 2020 to Aug. 25, 2026; EPA’s compliance samples are from Sept. 28, 2017 to Oct. 26, 2017; Pennsylvania’s PFAS results run from March 20, 2025 to Aug. 25, 2026.
Testing your own tap
No lab Pennsylvania certifies is within 75 miles of the area Cornerstone Living serves on the state’s list. Some take samples by mail; the state’s page lists them all.
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 PennsylvaniaSources
- EPA UCMR 5 occurrence data, file of Oct. 15, 2026
- Pennsylvania Department of Environmental Protection, Drinking Water Reporting System, PFAS results read Oct. 17, 2026
- EPA SDWA bulk download (SDWIS federal data), 2026 Q3
- Pennsylvania Department of Environmental Protection, Drinking Water Reporting System, results from Jan. 2, 2020 to Oct. 8, 2026, read Oct. 17, 2026
- EPA Six-Year Review 4 compliance monitoring data, 2012 to 2019, file of Feb. 5, 2024
- Limits and goals: each contaminant’s page, with its EPA source.
- How this page is built: methodology.
PWSID PA3391038. Rebuilt from EPA data on Oct. 18, 2026.
What to do next
- Read up on the 3 results above a lineWhat each one does to health, where it comes from, and the certification claim that addresses it.Start with PFOA
- Get the utility’s own reportCornerstone Living must send you a water quality report every year. It covers contaminants this page does not show, and has newer results than EPA’s national file for the ones here that come from it.How to read it
- Test your own tap for leadYour 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 filtersWhat the filters certified for these results cost over five years, cartridges included.Compare five-year costs