How many water violations are in St. Tammany Parish?

St. Tammany Parish has 7,149 total drinking water violations across 213 water systems, of which 1,932 are health-based violations. 78.9% of systems have at least one violation.

How many people get water from St. Tammany Parish systems?

Water systems in St. Tammany Parish serve approximately 266,825 people through 213 public water systems.

Has PFAS been detected in St. Tammany Parish water?

Under EPA UCMR5, 1 of 19 tested systems in St. Tammany Parish had at least one PFAS detection (5.3% of the UCMR5-tested subset - not of all 213 SDWIS systems).

What types of water sources supply St. Tammany Parish?

Water systems in St. Tammany Parish use GW (213 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. 27.0% of St. Tammany Parish's violations are health-based. Among counties with any SDWIS violations, this extract puts St. Tammany Parish in the higher health-based share band. Not all violations indicate immediate health risk, but they require corrective action.

Counties → Louisiana

St. Tammany Parish, Louisiana

Compiled by PlainWater · May 15, 2026

SDWIS compliance plate

Sheet LA103 · St. Tammany Parish 213 sys · 7,149 viol · #263/3254

VIOL-SEVERE · HEALTH-MID · RANK-TOP · BELOW-PEER · PFAS-LOW · SRC-GW · SYS-LARGE · BOOK-FULL

VIOL-SEVERE 78.9% flagged
HEALTH-MID 27.0% health
RANK-TOP #263/3254
BELOW-PEER 4.5 pp cleaner
PFAS-LOW 5.3% detect
SRC-GW GW lead 100%
SYS-LARGE 213 systems
BOOK-FULL 7/7 fields

Nearest flagged-rate peer: St. Helena Parish (+ 4.5 pp flagged-rate)

According to EPA SDWIS county population served used on /counties, St. Tammany Parish ranks #263 of 3,254 counties by people served, and #5 of 64 counties in Louisiana. See methodology · corpus placement.

St. Tammany Parish standing, lower-flagged corpus third

Flagged-system rate 78.9% is at or below the corpus lower third (≤ 92.7% flagged) across 2,973 counties with ≥3 SDWIS systems . Health-based share 27.0% is health-based share above the upper third (> 24.5%) . UCMR5 detect rate 5.3% is UCMR5 detect rate in the tested-pool middle third (≤ 33.3%) . Population served ranks #263 of 3,254 · #5 of 64 in Louisiana.

Water Systems

System Name	Population	Violations	PFAS
Slidell Water Supply	35,547	98	Clean
St Tam Parish- Bedico -Faubourg-Coquille	18,372	9	Clean
St Tam Parish - Briarwood Terrace	17,536	48	Clean
Covington Water Supply	16,185	76	Clean
Mandeville Water Supply	13,000	23	Clean
Utilities Inc - North Park Water Supply	11,298	27	Clean
Bayou Liberty Water Association	10,791	65	Clean
Magnolia-Eden Isles	10,155	28	Clean
Magnolia-Greenleaves	8,031	47	Clean
St Tam Parish - Cross Gates SD	7,791	49	Detected
Magnolia-Resolve Whisperwood	6,867	13	Clean
Utilities Inc - Kingspoint Subdivision	6,351	13	Clean
Lee Road Water Corporation	6,048	25	Clean
St. Tammany Water District #2	5,200	36	Clean
Magnolia-The Meadows	4,701	21	Clean
Beau Chene Water System	4,650	12	Clean
Magnolia-Lakeshore Estates	4,146	36	-
Abita Springs Water System	3,693	47	Clean
Town of Pearl River	3,333	22	Clean
St Tammany Water District 3	2,920	106	-
Magnolia-Guste Island	2,847	9	-
Utilities Inc - Lake Village SD	2,724	4	-
St Tam Parish Pineland Park Subd	2,500	15	-
Utilities Inc - Green Brier Water Supply	2,250	36	-
Utilities Inc - Huntwyck Village	2,088	13	-
Pelican Park	2,000	28	-
Folsom Water Supply	1,992	32	Clean
St Tam Parish -Northridge Estates	1,653	3	-
Utilities Inc - Magnolia Forest Subd	1,635	11	-
Utilities Inc - Woodridge Subdivision	1,590	6	-
Utilities Inc - Quail Ridge Subdivision	1,563	13	-
Magnolia-Monterey Subdivision	1,356	39	-
Tchefuncta Club Estates	1,245	38	-
Magnolia-Penn Mill Lakes	1,152	17	-
St Tam Parish - Medcath (la Heart)	1,001	6	-
Fontainebleau State Park	1,000	65	-
Knights of Columbus Bingo	1,000	4	-
Winn Dixie #1500	1,000	11	-
Lacombe Stores	999	3	-
St Tam Parish - River Oaks	930	1	-
Arby's	900	20	-
Villages of Bocage- Madisonville	894	18	-
Mayfield Elementary School	890	7	-
Madisonville Water Supply	871	8	-
Lake Ramsey	840	125	-
Magnolia-Money Hills Estates	825	18	-
Magnolia-River Park	822	0	-
Sunny Times 4 LLC	750	7	-
Lakeshore High School	750	4	-
Sun Water Supply	726	129	-

Compare beyond Louisiana

Lower-flagged peers for St. Tammany Parish

Cross-state counties nearest St. Tammany Parish on flagged-system share (78.9%) and cumulative violation count (7,149). 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. This page draws directly on EPA SDWIS data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.