Drinking water quality · 2025
· Verified
· PWSID NC0392020
What's in Cary, NC tap water
Only 8 of 27 core regulated contaminants were reported for Cary, NC. What was measured is clean — but most of the picture is missing.
- !2 contaminants within 20% of a limit
- !8 of 27 core regulated contaminants reported — 19 never appear in this report
- ✓Nothing over a federal limit
- ✓No open federal violations
+How this score is calculated
Every system starts at 100. Points come off for measured levels, for the federal violation record, and for how much of the core regulated set the utility actually reported. All three inputs are the utility's own published numbers and EPA's own records.
- −0 contaminants at or above a federal limit
- −8 contaminants within 20% of a limit
- −0 open health-based violations
- −0 open monitoring / reporting violations
- −2 health-based violations resolved in the last 5 years
- −17 core regulated contaminants never reported (8/27)
A 90–100 · B 80–89 · C 70–79 · D 60–69 · F below 60. A system reporting under a third of the core set is capped at C however clean its numbers look — a short report is not a clean bill of health.
Full grading methodology, constant for constant →What to worry about
- Chloramine98% of the federal limit1.33–3.91 mg/L · limit 4 mg/L
Holds disinfection further into the pipe network, but is regulated under the same residual-disinfectant cap as chlorine.
higher than 90% of U.S. systems
- Chlorine82% of the federal limit0.37–3.29 mg/L · limit 4 mg/L
Effective and necessary, but high residual levels can cause taste and odor issues; the EPA caps the residual disinfectant level.
higher than 90% of U.S. systems
+17 contaminants were measured and came in below the limitShow all
| Contaminant | Measured | Federal limit |
|---|---|---|
| TTHM | 37 ug/L | 80 ug/L |
| PFOA | 1.3 ng/L | 4 ng/L |
| Bromate | 0–3 ug/L | 10 ug/L |
| HAA5 | 17 ug/L | 60 ug/L |
| Fluoride | 0.65 mg/L | 4 mg/L |
| Turbidity | 0.1 NTU | 1 NTU |
| Copper | 0.096 mg/L | 1.3 mg/L |
| Lead | 0.0 mg/L | 0.015 mg/L |
| Hexafluoropropylene oxide dimer acid | Not detected ng/L | 10 ng/L |
| Perfluoroheptanoic acid | 1.1 ng/L | — |
| Perfluorohexanesulfonic acid | Not detected ng/L | 10 ng/L |
| PFOS | Not detected ng/L | 4 ng/L |
| TOC | 1.36–1.72 | — |
| PFHxA | 6.6 ng/L | — |
| PFPeA | 7 ng/L | — |
| PFBS | 3.4 ng/L | — |
| PFBA | 7.3 ng/L | — |
What this report doesn't tell you
19 of the 27 contaminants a community water system normally reports do not appear anywhere in Cary, NC's data. Absent is not the same as absent-from-the-water — it means nobody published a number.
+Full detail: PFAS testing, water source, historical monitoring, and the federal violation record
PFAS — EPA UCMR5 (2023–2025)
4 PFAS compounds detected in Cary, NC
The EPA finalized the first-ever federal drinking-water limits for six PFAS compounds in April 2024. These numbers come straight from EPA's UCMR5 lab dataset — every U.S. system serving more than 3,300 people tested every PFAS sample at an entry point to its distribution system. PFAS not listed below were either tested and not detected, or not yet sampled.
PFHxA
● Detected (no federal limit)PFPeA
● Detected (no federal limit)PFBS
● Detected (no federal limit)PFBA
● Detected (no federal limit)Where your water comes from · EPA SDWIS
Cary, NC's drinking water comes from surface water, drawn from 1 source.
Source
- JORDAN LAKE
Treatment
- TREATMENT_PLT_CARY/APEX WTP
Distribution
Also buys water from DURHAM, CITY OF, RALEIGH, CITY OF, and 2 more.
Compliance history
Federal Safe Drinking Water Act violation & enforcement records (EPA SDWIS). A violation is a regulatory determination by the state or EPA — separate from the measured levels above.
- Maximum contaminant level exceededHealth-based2 violations on record · most recent May 2023resolved
Source: EPA SDWIS / ECHO. View the full federal record on EPA ECHO ↗