How many water violations are in Johnston County?

Johnston County has 7,155 total drinking water violations across 54 water systems, of which 736 are health-based violations. 94.4% of systems have at least one violation.

How many people get water from Johnston County systems?

Water systems in Johnston County serve approximately 204,441 people through 54 public water systems.

Has PFAS been detected in Johnston County water?

Under EPA UCMR5, 9 of 9 tested systems in Johnston County had at least one PFAS detection (100.0% of the UCMR5-tested subset - not of all 54 SDWIS systems).

What types of water sources supply Johnston County?

Water systems in Johnston County use GW (32 systems), SW (22 systems) as their primary water sources.

Are health-based violations serious?

Health-based violations indicate that drinking water exceeded Maximum Contaminant Levels (MCLs) set by the EPA or failed treatment technique requirements. 10.3% of Johnston County's violations are health-based. Among counties with any SDWIS violations, this extract puts Johnston County in the lower health-based share band. Not all violations indicate immediate health risk, but they require corrective action.

Counties → North Carolina

County profile · EPA SDWIS + UCMR5

Johnston County, North Carolina

54 SDWIS-listed public water systems serve 204,441 people in Johnston County. Violation rates use that full inventory; PFAS rates use only the UCMR5-tested subset.

Compiled by PlainWater · May 15, 2026

54
SDWIS water systems Larger third of counties: 7,155
Total violations Upper third of counties: 94.4%
SDWIS systems w/ a violation Middle third of counties: 100.0%
UCMR5 PFAS rate (9 tested) Upper third of counties with tests

SDWIS compliance plate

Sheet NC101 · Johnston County 54 sys · 7,155 viol · #333/3254

VIOL-SEVERE · HEALTH-LOW · RANK-TOP · PHOTO-FINISH · PFAS-HIGH · SRC-GW · SYS-MID · BOOK-FULL

VIOL-SEVERE 94.4% flagged
HEALTH-LOW 10.3% health
RANK-TOP #333/3254
PHOTO-FINISH ±0.0 pp
PFAS-HIGH 100.0% detect
SRC-GW GW lead 59%
SYS-MID 54 systems
BOOK-FULL 7/7 fields

Nearest flagged-rate peer: Hoke County (+ 0 pp flagged-rate)

According to EPA SDWIS county population served used on /counties, Johnston County ranks #333 of 3,254 counties by people served, and #13 of 100 counties in North Carolina. See methodology · corpus placement.

Johnston County standing, mid-flagged corpus third

Flagged-system rate 94.4% is in the corpus middle third (≤ 100.0% flagged) across 2,973 counties with ≥3 SDWIS systems . Health-based share 10.3% is health-based share at or below the lower third (≤ 10.3%) . UCMR5 detect rate 100.0% is UCMR5 detect rate above the tested-pool upper third (> 33.3%) . Population served ranks #333 of 3,254 · #13 of 100 in North Carolina.

Water Systems

System Name	Population	Violations	PFAS
Johnston Co-West	92,365	20	Detected
Clayton, Town Of	29,689	121	Detected
Johnston Co-East	22,967	3	Detected
Smithfield, Town Of	12,900	238	Detected
Flowers Plantation	11,643	45	Detected
Selma, Town Of	6,190	190	Detected
Town of Clayton - North	4,523	5	-
Benson, Town Of	4,293	64	Detected
Four Oaks, Town Of	2,854	159	-
Pine Level, Town Of	2,413	425	-
Kenly, Town Of	2,301	223	-
Princeton, Town Of	1,326	207	-
Winston Pointe S/D	1,326	0	-
Smithfield South Water Dist	803	23	-
Buffalo Creek S/D	721	73	-
Southhills Southwoods SD	716	181	-
Selma, Town of (County Line)	642	43	Detected
Riverwood S/D	553	12	-
White Oak Plantation	521	74	-
Creekstone S/D	505	9	-
Micro, Town Of	470	764	-
Willowbrook Development	432	100	-
Creekside Place S/D	361	8	-
South Plantation S/D	357	7	-
Ole Mill Stream S/D	325	6	-
Stephanie Woods S/D	245	10	-
Pine Level, Town of (Firetower)	238	238	-
Winston Plantation	229	0	-
Tucker Lake	200	93	-
Neuse Colony S/D Section B	190	56	-
Dutchess Downs Mh S/D	185	151	-
Southgate S/D	160	56	Detected
Country Hills S/D	152	112	-
Tippetts Chapel Fwb Church	130	136	-
Southfort S/D	125	3	-
Deerfield S/D	120	6	-
Garner Estates Mh S/D	114	130	-
Heather Downs Mh S/D	112	13	-
Cleveland MHP	107	654	-
Micro, Town of (County Line)	107	245	-
Smithfield Moose Lodge	100	89	-
Shadow Lakes S/D	99	3	-
Albany Acres S/D	81	6	-
Stoneybrook Estates S/D	80	35	-
Adams MHP	80	1,585	-
Gibson Glen S/D	60	3	-
Neighbor`s Walk S/D	60	0	-
Paceville S/D	58	137	-
Clemmons State Forest	50	34	-
Heatherstone S/D	48	6	-

Compare beyond North Carolina

Mid-flagged peers for Johnston County

Cross-state counties nearest Johnston County on flagged-system share (94.4%) and cumulative violation count (7,155). In-state neighbours stay on the compliance plate above.

Similar flagged-system rate

Nearest cross-state counties by % of SDWIS systems with at least one violation on record.

4 peers

Similar violation load

Nearest cross-state counties by cumulative SDWIS violation count (all systems in the county).

4 peers

Read our methodology · Check your water system - how this data is sourced, computed, and verified.

Data sourced from EPA SDWIS and UCMR5 PFAS monitoring data. See our methodology for details. Retrieved and formatted by PlainWater

Compiled by PlainWater, Drinking Water Quality Editorial Process · May 15, 2026

Every figure on PlainWater is rendered directly from EPA SDWIS drinking-water data, no number is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.