Sligo Water System Incorporated
What EPA’s and CDC’s records show in this utility’s water: nitrate, arsenic and other regulated chemicals; lead and copper; and violations since 2016, with the certification that handles each result.
- Serves
- 2,850 people
- Connections
- 950
- Water source
- Groundwater
- Based in
- Coushatta, LA
- County
- Bossier Parish
- Owner
- Private
The ZIP code it serves
The short answer
1 result is above EPA’s legal limit, and 1 more is above the health goal. The worst: Copper, above the action level. 8 health-based violations since 2016.
What handles itWhat was found
Lead and copper: EPA SDWIS monitoring periods ending 2017 to 2020.
Arsenic, total trihalomethanes (TTHM), nitrate, haloacetic acids (HAA5) and uranium: Louisiana’s yearly averages per water system, as CDC’s Environmental Public Health Tracking Network publishes them, 2020 to 2022, with EPA’s 2012 to 2019 file for earlier years.
Fluoride and chromium (total): EPA’s compliance monitoring file, samples taken from Oct. 27, 2014 to Oct. 2, 2017. Newer results are in the utility’s annual water quality report.
Above the legal limit1
Copper
Comes from pipes, often your own
1.9ppm
90th percentile, 2020
In the latest period, 9 in 10 homes sampled were at or below 1.9 ppm, above EPA’s action level of 1.3 ppm.
What handles it
- NSF/ANSI 53 look for “Copper Reduction”
- NSF/ANSI 58 look for “Copper Reduction”
Above the health goal1
Arsenic
Comes from the source
4.1ppb
Highest yearly average, 2020 to 2022
2022 average: 4.0 ppb
Averaged by year, the highest was 4.1 ppb, in 2021: below EPA’s legal limit of 10 ppb, but above its health goal of zero. In 2022, the latest year on file, it averaged 4.0 ppb. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 16.9 ppb, in 2018, and EPA recorded a violation in 2018.
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 limits4
Total trihalomethanes (TTHM)
Forms or is added in treatment
21.6ppb
Highest yearly average, 2020 to 2022
2022 average: 2.2 ppb
Averaged by year, the highest was 21.6 ppb, in 2020, below EPA’s legal limit of 80 ppb. In 2022, the latest year on file, it averaged 2.2 ppb. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 11.6 ppb, in 2013.
What handles it
- NSF/ANSI 53 look for “Trihalomethanes (TTHM) Reduction”
- NSF/ANSI 58 look for “Trihalomethanes (TTHM) Reduction”
Nitrate
Comes from the source
0.8ppm
Highest yearly average, 2022
Averaged by year, the highest was 0.8 ppm, in 2022, below EPA’s legal limit of 10 ppm. That is the only year on file. Earlier, from 2012 to 2019, EPA’s file shows a highest sample of 1.2 ppm, in 2017.
What handles it
- NSF/ANSI 58 look for “Nitrate/Nitrite Reduction”
- NSF/ANSI 53 look for “Nitrate/Nitrite (30 ppm challenge)”
Fluoride
Forms or is added in treatment
0.16ppm
Highest yearly average, 2014 to 2017
Averaged by year, the highest was 0.16 ppm, in 2017, below EPA’s legal limit of 4.0 ppm. Its highest single sample was 0.21 ppm. That was also the latest year on file.
What handles it
- NSF/ANSI 58 look for “Fluoride Reduction”
- NSF/ANSI 53 look for “Fluoride”
Haloacetic acids (HAA5)
Forms or is added in treatment
1.6ppb
Highest yearly average, 2020 to 2022
2022 average: 0.77 ppb
Averaged by year, the highest was 1.6 ppb, in 2021, below EPA’s legal limit of 60 ppb. In 2022, the latest year on file, it averaged 0.77 ppb. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 9.3 ppb, in 2013.
What handles it
No certification claim covers this compound yet.
3 compounds tested and not foundBelow the reporting level in every sample. Not found is not the same as zero.
- Chromium (total)
- Lead
- Uranium
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: Copper Reduction, Arsenic (Pentavalent)<=50 ppb Reduction
For: Copper, Arsenic
Other certifiers’ wording: Arsenic (III) (50 ppb influent level)
- NSF/ANSI 58
Claims: Copper Reduction, Arsenic (Pentavalent)<=50 ppb Reduction
For: Copper, Arsenic
Other certifiers’ wording: Arsenic (Pentavalent)<=300 ppb Reduction; Arsenic (V) (300 ppb influent level)
At the tap, or for the whole house?
Lead and copper usually come from pipes and fixtures inside or near your home. A whole-house system sits where water enters, so it cannot catch what your own plumbing adds after it. For those, the filter that counts is the one at the tap. 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
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: Copper, 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: Copper, Arsenic
Countertop reverse osmosis
- IAPMO listing:NSF/ANSI 42NSF/ANSI 53NSF/ANSI 58NSF/ANSI 401checked Oct. 4, 2026
Certified for: Copper, Arsenic
Brita Tahoe Pitcher with Original Filter (OB60, OB03)
Pitcher
- WQA listing:NSF/ANSI 42NSF/ANSI 53checked Oct. 13, 2026
Certified for: Copper
Violations since 2016
| Contaminant or rule | Type | Period | Measured | Status |
|---|---|---|---|---|
| Groundwater Rule | A significant problem found in a state inspection was not fixed on time.EPA: Failure To Address Deficiency | June 2, 2021 | — | Resolved |
| Groundwater Rule | A significant problem found in a state inspection was not fixed on time.EPA: Failure To Address Deficiency | June 2, 2021 | — | Unaddressed |
| Lead and Copper Rule | A required study or plan for corrosion control was not done on time.EPA: OCCT/SOWT Study/Recommendation | Jan. 11, 2020 | — | Resolved |
| Arsenic | The running average was above the legal limit.EPA: Maximum Contaminant Level Violation, Average | Oct. 1, 2018 to Dec. 31, 2018 | 0.029 MG/L | Resolved |
| Lead and Copper Rule | A required study or plan for corrosion control was not done on time.EPA: OCCT/SOWT Study/Recommendation | July 31, 2018 | — | Resolved |
| Arsenic | The running average was above the legal limit.EPA: Maximum Contaminant Level Violation, Average | July 1, 2018 to Sept. 30, 2018 | 0.038 MG/L | Resolved |
| Lead and Copper Rule | A required study or plan for corrosion control was not done on time.EPA: OCCT/SOWT Study/Recommendation | Jan. 11, 2018 | — | Resolved |
| Arsenic | The running average was above the legal limit.EPA: Maximum Contaminant Level Violation, Average | Jan. 1, 2018 to March 31, 2018 | 0.056 MG/L | Resolved |
| Health-based violations only. Resolved and archived mean the utility returned to compliance or the state closed the record. 32 monitoring or reporting violations not shown. | ||||
What this report can’t tell you
Everything else. Arsenic, total trihalomethanes (TTHM), nitrate, haloacetic acids (HAA5) and uranium results here are Louisiana’s yearly averages as CDC publishes them, from 2020 on, with EPA’s national file for 2012 to 2019. Fluoride and chromium (total) come from EPA’s file alone, which ends in 2019. Sligo Water System Incorporated’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; CDC’s yearly averages for Louisiana cover 2020 to 2022; EPA’s compliance samples are from Oct. 27, 2014 to Oct. 2, 2017.
Testing your own tap
The lab Louisiana certifies closest to the area Sligo Water System Incorporated serves, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.
LDH Shreveport Regional Laboratory
Shreveport, LA · about 14 miles
Certified for bacteria
Sources
- EPA UCMR 5 occurrence data, file of Oct. 15, 2026
- EPA SDWA bulk download (SDWIS federal data), 2026 Q3
- CDC Environmental Public Health Tracking Network, yearly averages Louisiana supplied to CDC, 2020 to 2022, read Oct. 8, 2026. TapBuff’s comparisons with EPA’s limits are its own, not CDC’s or Louisiana’s.
- EPA Six-Year Review 4 compliance monitoring data, 2012 to 2019, file of Feb. 5, 2024
- Certified labs: LDH, laboratories certified by Louisiana for drinking water analysis, read Oct. 16, 2026; distances from the Census 2020 ZIP code tabulation area gazetteer
- Limits and goals: each contaminant’s page, with its EPA source.
- How this page is built: methodology.
PWSID LA1015044. Rebuilt from EPA data on Oct. 18, 2026.
What to do next
- Read up on the 2 results above a lineWhat each one does to health, where it comes from, and the certification claim that addresses it.Start with Copper
- Get the utility’s own reportSligo Water System Incorporated 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