Wake County Water Quality: 4 Cities Ranked by the Records
Wake County, North Carolina: 4 city reports built from EPA and utility records. A county has many suppliers; each city shows the system that serves it.
Highest result for each contaminant
One row per contaminant: the highest result any system in the county reported, against its limit. Open a row for the systems behind it.
Perfluorooctanesulfonic acid (PFOS)Detected in 2 systems of 4 tested4.0 ng/L federal MCL (2024) · US EPAHighest12 ng/L
- HOLLY SPRINGS, TOWN OF12 ng/LSample date: 2024-02-06 to 2024-11-06
- RALEIGH, CITY OF5.6 ng/LSample date: 2023-04-03 to 2024-03-19
- APEX, TOWN OFNot detected · below 4.0 ng/L lab reporting limitSample date: 2023-08-29 to 2024-05-15
- CARY, TOWN OFNot detected · below 4.0 ng/L lab reporting limitSample date: 2025-02-11 to 2025-11-04
Perfluorooctanoic acid (PFOA)Detected in 1 system of 4 tested4.0 ng/L federal MCL (2024) · US EPAHighest5.9 ng/L
- HOLLY SPRINGS, TOWN OF5.9 ng/LSample date: 2024-02-06 to 2024-11-06
- APEX, TOWN OFNot detected · below 4.0 ng/L lab reporting limitSample date: 2023-08-29 to 2024-05-15
- CARY, TOWN OFNot detected · below 4.0 ng/L lab reporting limitSample date: 2025-02-11 to 2025-11-04
- RALEIGH, CITY OFNot detected · below 4.0 ng/L lab reporting limitSample date: 2023-04-03 to 2024-03-19
Total trihalomethanes (TTHM)Detected in 1 system80 ppb federal MCL · US EPAHighest37 ppb
- CARY, TOWN OF37 ppbReporting year: 2025
Perfluorohexanesulfonic acid (PFHxS)Detected in 1 system of 4 tested10 ng/L federal MCL (2024) · US EPAHighest3.2 ng/L
- HOLLY SPRINGS, TOWN OF3.2 ng/LSample date: 2024-02-06 to 2024-11-06
- APEX, TOWN OFNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-08-29 to 2024-05-15
- CARY, TOWN OFNot detected · below 3.0 ng/L lab reporting limitSample date: 2025-02-11 to 2025-11-04
- RALEIGH, CITY OFNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-04-03 to 2024-03-19
Haloacetic acids (HAA5)Detected in 1 system60 ppb federal MCL · US EPAHighest17 ppb
- CARY, TOWN OF17 ppbReporting year: 2025
Perfluorobutanesulfonic acid (PFBS)Detected in 4 systems2,000 ng/L EPA health advisory (screening, not a legal limit) · US EPAHighest4.5 ng/L
- HOLLY SPRINGS, TOWN OF4.5 ng/LSample date: 2024-02-06 to 2024-11-06
- APEX, TOWN OF4 ng/LSample date: 2023-08-29 to 2024-05-15
- CARY, TOWN OF3.4 ng/LSample date: 2025-02-11 to 2025-11-04
- RALEIGH, CITY OF3.3 ng/LSample date: 2023-04-03 to 2024-03-19
Perfluorohexanoic acid (PFHxA)Detected in 4 systems400,000 ng/L Michigan EGLE state MCL (strictest US state) · Michigan EGLEHighest7.4 ng/L
- HOLLY SPRINGS, TOWN OF7.4 ng/LSample date: 2024-02-06 to 2024-11-06
- APEX, TOWN OF6.8 ng/LSample date: 2023-08-29 to 2024-05-15
- CARY, TOWN OF6.6 ng/LSample date: 2025-02-11 to 2025-11-04
- RALEIGH, CITY OF4.2 ng/LSample date: 2023-04-03 to 2024-03-19
Water hardnessDetected in 2 systemsAesthetic, no federal health limit · USGSHighest1.6 gpg
- CARY, TOWN OF1.6 gpgReporting year: 2025
- RALEIGH, CITY OF1.5 gpgReporting year: 2025
3 more contaminants detectedShow
Perfluorobutanoic acid (PFBA)Detected in 4 systemsNo federal or state limit; shown for transparencyHighest9 ng/L
- RALEIGH, CITY OF9 ng/LSample date: 2023-04-03 to 2024-03-19
- APEX, TOWN OF8.9 ng/LSample date: 2023-08-29 to 2024-05-15
- CARY, TOWN OF7.3 ng/LSample date: 2025-02-11 to 2025-11-04
- HOLLY SPRINGS, TOWN OF7 ng/LSample date: 2024-02-06 to 2024-11-06
Perfluoroheptanoic acid (PFHpA)Detected in 1 system of 4 testedNo federal or state limit; shown for transparencyHighest3.4 ng/L
- HOLLY SPRINGS, TOWN OF3.4 ng/LSample date: 2024-02-06 to 2024-11-06
- APEX, TOWN OFNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-08-29 to 2024-05-15
- CARY, TOWN OFNot detected · below 3.0 ng/L lab reporting limitSample date: 2025-02-11 to 2025-11-04
- RALEIGH, CITY OFNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-04-03 to 2024-03-19
Perfluoropentanoic acid (PFPeA)Detected in 4 systemsNo federal or state limit; shown for transparencyHighest8.1 ng/L
- HOLLY SPRINGS, TOWN OF8.1 ng/LSample date: 2024-02-06 to 2024-11-06
- APEX, TOWN OF7.8 ng/LSample date: 2023-08-29 to 2024-05-15
- CARY, TOWN OF7 ng/LSample date: 2025-02-11 to 2025-11-04
- RALEIGH, CITY OF4.3 ng/LSample date: 2023-04-03 to 2024-03-19
23 substances tested, none detected in any systemShow
Tested in these 4 systems: APEX, TOWN OF, CARY, TOWN OF, HOLLY SPRINGS, TOWN OF, RALEIGH, CITY OF
- 11-Chloroeicosafluoro-3-oxaundecane-1-sulfonic acid (11Cl-PF3OUdS)
- 1H, 1H, 2H, 2H-perfluorodecane sulfonic acid (8:2 FTS)
- 1H, 1H, 2H, 2H-perfluorohexane sulfonic acid (4:2 FTS)
- 1H, 1H, 2H, 2H-perfluorooctane sulfonic acid (6:2 FTS)
- 4,8-Dioxa-3H-perfluorononanoic acid (ADONA)
- 9-Chlorohexadecafluoro-3-oxanone-1-sulfonic acid (9Cl-PF3ONS)
- Hexafluoropropylene oxide dimer acid (HFPO-DA) (GenX chemicals)
- Lead (90th percentile)
- Lithium
- N-ethyl perfluorooctanesulfonamidoacetic acid (NEtFOSAA)
- N-methyl perfluorooctanesulfonamidoacetic acid (NMeFOSAA)
- Nonafluoro-3,6-dioxaheptanoic acid (NFDHA)
- Perfluoro (2-ethoxyethane) sulfonic acid (PFEESA)
- Perfluoro-3-methoxypropanoic acid (PFMPA)
- Perfluoro-4-methoxybutanoic acid (PFMBA)
- Perfluorodecanoic acid (PFDA)
- Perfluorododecanoic acid (PFDoA)
- Perfluoroheptanesulfonic acid (PFHpS)
- Perfluorononanoic acid (PFNA)
- Perfluoropentanesulfonic acid (PFPeS)
- Perfluorotetradecanoic acid (PFTA)
- Perfluorotridecanoic acid (PFTrDA)
- Perfluoroundecanoic acid (PFUnA)
Cities ranked by the records
Ranked by the Purity Score of each city's main water system, highest first. Scores belong to water systems; there is no county score. The score is computed only from contaminants measured in the published EPA record, so this ranks the record, not which city's water is safest. How the score works.
0of 4 cities above the 15 µg/L action level
Based on each system's 90th-percentile result. Lead from household plumbing isn't in this record.
Lead in North Carolina2cities report hardness · hardest Cary, 1.6 gpg
None above 7 gpg, the USGS threshold for hard water. An aesthetic measure with no federal health limit.
Hard water explainedLargest water systems
- RaleighRALEIGH, CITY OF · NC0392010650,000 served
- CaryCARY, TOWN OF · NC0392020227,300 served
- ApexAPEX, TOWN OF · NC039204583,001 served
- Holly SpringsHOLLY SPRINGS, TOWN OF · NC039205051,947 served
Frequently asked
How does Wake County tap water compare across cities?
PurityMap ranks 4 cities in Wake County by the Purity Score of each city's main water system, computed only from contaminants measured in the published EPA record. Scores belong to water systems, not to cities. The highest published score is Apex's main water system: APEX, TOWN OF · PWSID NC0392045 · Purity Score 100 (Excellent) · Confidence: moderate · Assessed at the water-system level. The ranking compares the records, not which city's water is safest, and your own tap can differ with household plumbing.
How many Wake County cities had a PFAS sample above a 2024 EPA limit?
2 of 4 Wake County city reports had a PFAS sample above a 2024 EPA limit in EPA's UCMR 5 testing, including Holly Springs (PFOS 12 ng/L), Raleigh (PFOS 5.6 ng/L). That limit is judged on a yearly average, and water systems have until 2029 to meet it, so a single sample is not a violation. PFAS were detected at any level in 4.
Is there lead in Wake County tap water?
Utilities report lead as a 90th-percentile result from home taps. 0 of 4 Wake County cities reported a value above zero, and none was above the 15 µg/L federal action level. Lead usually comes from a building's own pipes and fixtures, so only a test at your tap tells you what you drink.
Have Wake County water systems had drinking-water violations?
1 city in Wake County has a health-based violation in the federal SDWIS record within about the last ten years. Each city report lists the contaminant, year and whether it was resolved.
Does Wake County have hard water?
Hardness is published in utility water-quality reports for 2 Wake County cities on record; the hardest is Cary at 1.6 grains per gallon. Hardness affects scale and appliances; it is not a health finding.
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