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This is a rebuild of Drinking Water Watch and not yet the official record. Use the agency’s current Drinking Water Watch for anything you need to rely on.

Chemical and radiological sample results

MS0230001 , City of Bay St Louis

43 of the 75 analytes this system has been tested for have been detected at least once, across 676 samples on record.

The other 32 were tested for and never found. An analyte is counted here if any result on record measured it, so this covers the whole history and not the samples listed below.

Across all 676 samples on record, detections range from October 15, 1992 to July 8, 2026. These figures cover the whole record; the list of samples further down is narrowed.

What counts as a non-detect is defined in the help: Less than Indicator. This system’s violations.

What has been detected, ever

Every analyte measured above its reporting level at any point in this system’s record, most often detected first. This is not limited to the samples listed below.

Every analyte ever detected for City of Bay St Louis, with how many results found it and when it was first and last detected. Covers the whole record, not only the samples listed below.
Analyte Kind Detected in First detected Last detected
Copper, Free 1022 Inorganic Chemical 251 of 319 results Oct 15, 1992 Sep 26, 2024
Lead 1030 Inorganic Chemical 214 of 319 results Oct 15, 1992 Sep 26, 2024
Total Haloacetic Acids (Haa5) 2456 Organic Chemical 51 of 51 results Mar 17, 2004 Jun 30, 2026
TTHM 2950 Organic Chemical 51 of 51 results Mar 17, 2004 Jun 30, 2026
Fluoride 1025 Inorganic Chemical 46 of 46 results Jul 16, 2002 Jul 8, 2026
Barium 1010 Inorganic Chemical 42 of 42 results Jul 16, 2002 Jul 8, 2026
Chromium 1020 Inorganic Chemical 34 of 42 results Jul 16, 2002 Feb 5, 2025
Dichloroacetic Acid 2451 Organic Chemical 16 of 16 results Sep 17, 2008 Jun 30, 2026
Sodium 1052 Inorganic Chemical 16 of 16 results May 18, 2011 Jan 31, 2024
Chloroform 2941 Organic Chemical 15 of 16 results Sep 17, 2008 Jun 30, 2026
Nickel 1036 Inorganic Chemical 14 of 38 results Jul 16, 2002 Feb 5, 2025
Trichloroacetic Acid 2452 Organic Chemical 12 of 16 results Apr 13, 2009 Jun 30, 2026
Gross Alpha, Incl. Radon & U 4002 Radionuclide 11 of 11 results Mar 7, 2012 Apr 20, 2013
Gross Alpha Particle Activity 4109 Radionuclide 10 of 11 results Sep 17, 2009 Sep 16, 2013
Monochloroacetic Acid 2450 Organic Chemical 8 of 16 results Apr 13, 2009 Jul 25, 2018
Bromodichloromethane 2943 Organic Chemical 7 of 16 results Apr 13, 2009 Jun 30, 2026
Arsenic 1005 Inorganic Chemical 7 of 42 results Mar 9, 2005 Feb 5, 2025
Combined Radium (-226 & -228) 4010 Radionuclide 6 of 22 results Sep 17, 2009 Mar 3, 2010
Radium-226 4020 Radionuclide 6 of 22 results Sep 17, 2009 Mar 3, 2010
Gross Beta Particle Activity 4100 Radionuclide 6 of 6 results Sep 17, 2009 Mar 3, 2010
Selenium 1045 Inorganic Chemical 6 of 42 results Mar 9, 2005 Apr 2, 2008
Gross Alpha, Excl. Radon & U 4000 Radionuclide 5 of 6 results Sep 17, 2009 Mar 3, 2010
Dibromochloromethane 2944 Organic Chemical 4 of 16 results Apr 13, 2009 Jun 30, 2026
Calcium 1016 Inorganic Chemical 4 of 4 results May 18, 2011 Mar 29, 2017
Chloride 1017 Inorganic Chemical 4 of 4 results May 18, 2011 Mar 29, 2017
Magnesium 1031 Inorganic Chemical 4 of 4 results May 18, 2011 Mar 29, 2017
Manganese 1032 Inorganic Chemical 4 of 4 results May 18, 2011 Mar 29, 2017
Potassium 1042 Inorganic Chemical 4 of 4 results May 18, 2011 Mar 29, 2017
Residue, Total, Filterable 1057 Water Quality 4 of 4 results May 18, 2011 Mar 29, 2017
Alkalinity, Caco3 Stability 1067 Water Quality 4 of 4 results May 18, 2011 Mar 29, 2017
Color 1905 Water Quality 4 of 4 results May 18, 2011 Mar 29, 2017
Hardness, Total (As Caco3) 1915 Water Quality 4 of 4 results May 18, 2011 Mar 29, 2017
Alkalinity, Total 1927 Water Quality 4 of 4 results May 18, 2011 Mar 29, 2017
Calculated Sodium NACA Water Quality 4 of 4 results May 18, 2011 Mar 29, 2017
PH, Field Result PHFD Water Quality 4 of 4 results May 18, 2011 Mar 29, 2017
Monobromoacetic Acid 2453 Organic Chemical 4 of 16 results Sep 17, 2008 Jan 5, 2010
Iron 1028 Inorganic Chemical 3 of 4 results Mar 29, 2017 Mar 29, 2017
Sulfate 1055 Inorganic Chemical 3 of 12 results Jul 16, 2002 Mar 29, 2017
Radium-228 4030 Radionuclide 3 of 22 results Sep 17, 2009 Mar 3, 2010
Cyanide 1024 Inorganic Chemical 2 of 38 results Sep 19, 2011 Sep 19, 2011
Cadmium 1015 Inorganic Chemical 2 of 42 results Mar 9, 2005 Mar 9, 2005
Carbon Tetrachloride 2982 Organic Chemical 1 of 31 results May 4, 2022 May 4, 2022
Carbon Dioxide 1901 Water Quality 1 of 1 result May 18, 2011 May 18, 2011

Showing samples collected between September 26, 2024 and September 26, 2026. That is this page’s default, not a limit on what the agency records.

Show every sample on record

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The most recent samples, result by result

The table below lists 1–10 of 34 samples, newest first — collected June 18, 2025 to July 8, 2026. The summary above covers all 34.

56 results from the 10 samples listed here: 19 detected, 37 not detected. Across the whole record it is 905 of 2,496. A sample is analysed for many analytes at once, so one sample appears on as many rows as it had results.

We withheld the location of 2 sampling points below. The location on record identifies a private home, and we do not publish those. That is our decision, not the agency’s. The sampling point, its type and every result taken there are published unchanged.

Chemical and radiological sample results for City of Bay St Louis, every result from 1 to 10 of 34 samples shown, newest first. Not detected means the amount was below the level the laboratory can reliably report, which is given beside it.
Result Analyte Monitoring period
Collected
Jul 8, 2026
Sampling point
TF105 Treatment Plant T105
Sample type
Routine
Lab sample
35049767004
Laboratory
Pace Analytical Services, LLC
Not detected below 1 ug/l Minimum Reporting Level , sample collected Jul 8, 2026, sampling point TF105 Arsenic 1005 EPA method 200.8 Jan 1, 2026 – Dec 31, 2031
14.3 ug/l , sample collected Jul 8, 2026, sampling point TF105 Barium 1010 EPA method 200.8 Jan 1, 2026 – Dec 31, 2031
Not detected below 0.2 ug/l Minimum Reporting Level , sample collected Jul 8, 2026, sampling point TF105 Cadmium 1015 EPA method 200.8 Jan 1, 2026 – Dec 31, 2031
Not detected below 2 ug/l Minimum Reporting Level , sample collected Jul 8, 2026, sampling point TF105 Chromium 1020 EPA method 200.8 Jan 1, 2026 – Dec 31, 2031
0.47 mg/l , sample collected Jul 8, 2026, sampling point TF105 Fluoride 1025 EPA method 300.0 Jan 1, 2026 – Dec 31, 2031
Not detected below 0.2 ug/l Minimum Reporting Level , sample collected Jul 8, 2026, sampling point TF105 Mercury 1035 EPA method 245.1 Jan 1, 2026 – Dec 31, 2031
Not detected below 1 ug/l Minimum Reporting Level , sample collected Jul 8, 2026, sampling point TF105 Selenium 1045 EPA method 200.8 Jan 1, 2026 – Dec 31, 2031
Not detected below 1 ug/l Minimum Reporting Level , sample collected Jul 8, 2026, sampling point TF105 Antimony, Total 1074 EPA method 200.8 Jan 1, 2026 – Dec 31, 2031
Not detected below 0.1 ug/l Minimum Reporting Level , sample collected Jul 8, 2026, sampling point TF105 Beryllium, Total 1075 EPA method 200.8 Jan 1, 2026 – Dec 31, 2031
Not detected below 1 ug/l Minimum Reporting Level , sample collected Jul 8, 2026, sampling point TF105 Thallium, Total 1085 EPA method 200.8 Jan 1, 2026 – Dec 31, 2031
Collected
Jul 8, 2026
Sampling point
TF104 Treatment Plant T104
Sample type
Routine
Lab sample
35049767003
Laboratory
Pace Analytical Services, LLC
Not detected below 1 ug/l Minimum Reporting Level , sample collected Jul 8, 2026, sampling point TF104 Arsenic 1005 EPA method 200.8 Jan 1, 2026 – Dec 31, 2031
13.9 ug/l , sample collected Jul 8, 2026, sampling point TF104 Barium 1010 EPA method 200.8 Jan 1, 2026 – Dec 31, 2031
Not detected below 0.2 ug/l Minimum Reporting Level , sample collected Jul 8, 2026, sampling point TF104 Cadmium 1015 EPA method 200.8 Jan 1, 2026 – Dec 31, 2031
Not detected below 2 ug/l Minimum Reporting Level , sample collected Jul 8, 2026, sampling point TF104 Chromium 1020 EPA method 200.8 Jan 1, 2026 – Dec 31, 2031
0.52 mg/l , sample collected Jul 8, 2026, sampling point TF104 Fluoride 1025 EPA method 300.0 Jan 1, 2026 – Dec 31, 2031
Not detected below 0.2 ug/l Minimum Reporting Level , sample collected Jul 8, 2026, sampling point TF104 Mercury 1035 EPA method 245.1 Jan 1, 2026 – Dec 31, 2031
Not detected below 1 ug/l Minimum Reporting Level , sample collected Jul 8, 2026, sampling point TF104 Selenium 1045 EPA method 200.8 Jan 1, 2026 – Dec 31, 2031
Not detected below 1 ug/l Minimum Reporting Level , sample collected Jul 8, 2026, sampling point TF104 Antimony, Total 1074 EPA method 200.8 Jan 1, 2026 – Dec 31, 2031
Not detected below 0.1 ug/l Minimum Reporting Level , sample collected Jul 8, 2026, sampling point TF104 Beryllium, Total 1075 EPA method 200.8 Jan 1, 2026 – Dec 31, 2031
Not detected below 1 ug/l Minimum Reporting Level , sample collected Jul 8, 2026, sampling point TF104 Thallium, Total 1085 EPA method 200.8 Jan 1, 2026 – Dec 31, 2031
Collected
Jul 8, 2026
Sampling point
TF103 Treatment Plant T103
Sample type
Routine
Lab sample
35049767002
Laboratory
Pace Analytical Services, LLC
Not detected below 1 ug/l Minimum Reporting Level , sample collected Jul 8, 2026, sampling point TF103 Arsenic 1005 EPA method 200.8 Jan 1, 2026 – Dec 31, 2031
12.4 ug/l , sample collected Jul 8, 2026, sampling point TF103 Barium 1010 EPA method 200.8 Jan 1, 2026 – Dec 31, 2031
Not detected below 0.2 ug/l Minimum Reporting Level , sample collected Jul 8, 2026, sampling point TF103 Cadmium 1015 EPA method 200.8 Jan 1, 2026 – Dec 31, 2031
Not detected below 2 ug/l Minimum Reporting Level , sample collected Jul 8, 2026, sampling point TF103 Chromium 1020 EPA method 200.8 Jan 1, 2026 – Dec 31, 2031
0.32 mg/l , sample collected Jul 8, 2026, sampling point TF103 Fluoride 1025 EPA method 300.0 Jan 1, 2026 – Dec 31, 2031
Not detected below 0.2 ug/l Minimum Reporting Level , sample collected Jul 8, 2026, sampling point TF103 Mercury 1035 EPA method 245.1 Jan 1, 2026 – Dec 31, 2031
Not detected below 1 ug/l Minimum Reporting Level , sample collected Jul 8, 2026, sampling point TF103 Selenium 1045 EPA method 200.8 Jan 1, 2026 – Dec 31, 2031
Not detected below 1 ug/l Minimum Reporting Level , sample collected Jul 8, 2026, sampling point TF103 Antimony, Total 1074 EPA method 200.8 Jan 1, 2026 – Dec 31, 2031
Not detected below 0.1 ug/l Minimum Reporting Level , sample collected Jul 8, 2026, sampling point TF103 Beryllium, Total 1075 EPA method 200.8 Jan 1, 2026 – Dec 31, 2031
Not detected below 1 ug/l Minimum Reporting Level , sample collected Jul 8, 2026, sampling point TF103 Thallium, Total 1085 EPA method 200.8 Jan 1, 2026 – Dec 31, 2031
Collected
Jul 8, 2026
Sampling point
TF101 Treatment Plant T101
Sample type
Routine
Lab sample
35049767001
Laboratory
Pace Analytical Services, LLC
Not detected below 1 ug/l Minimum Reporting Level , sample collected Jul 8, 2026, sampling point TF101 Arsenic 1005 EPA method 200.8 Jan 1, 2026 – Dec 31, 2031
12.8 ug/l , sample collected Jul 8, 2026, sampling point TF101 Barium 1010 EPA method 200.8 Jan 1, 2026 – Dec 31, 2031
Not detected below 0.2 ug/l Minimum Reporting Level , sample collected Jul 8, 2026, sampling point TF101 Cadmium 1015 EPA method 200.8 Jan 1, 2026 – Dec 31, 2031
Not detected below 2 ug/l Minimum Reporting Level , sample collected Jul 8, 2026, sampling point TF101 Chromium 1020 EPA method 200.8 Jan 1, 2026 – Dec 31, 2031
0.55 mg/l , sample collected Jul 8, 2026, sampling point TF101 Fluoride 1025 EPA method 300.0 Jan 1, 2026 – Dec 31, 2031
Not detected below 0.2 ug/l Minimum Reporting Level , sample collected Jul 8, 2026, sampling point TF101 Mercury 1035 EPA method 245.1 Jan 1, 2026 – Dec 31, 2031
Not detected below 1 ug/l Minimum Reporting Level , sample collected Jul 8, 2026, sampling point TF101 Selenium 1045 EPA method 200.8 Jan 1, 2026 – Dec 31, 2031
Not detected below 1 ug/l Minimum Reporting Level , sample collected Jul 8, 2026, sampling point TF101 Antimony, Total 1074 EPA method 200.8 Jan 1, 2026 – Dec 31, 2031
Not detected below 0.1 ug/l Minimum Reporting Level , sample collected Jul 8, 2026, sampling point TF101 Beryllium, Total 1075 EPA method 200.8 Jan 1, 2026 – Dec 31, 2031
Not detected below 1 ug/l Minimum Reporting Level , sample collected Jul 8, 2026, sampling point TF101 Thallium, Total 1085 EPA method 200.8 Jan 1, 2026 – Dec 31, 2031
Collected
Jun 30, 2026 12:05
Sampling point
SM2 Location withheld
Sample type
Routine
Lab sample
810-198100-1
Laboratory
Eurofins Eaton Analytical South Bend in
Not detected below 2 ug/l Minimum Reporting Level , sample collected Jun 30, 2026 12:05, sampling point SM2 Monochloroacetic Acid 2450 EPA method 552.2 Not recorded
14 ug/l , sample collected Jun 30, 2026 12:05, sampling point SM2 Dichloroacetic Acid 2451 EPA method 552.2 Not recorded
14 ug/l , sample collected Jun 30, 2026 12:05, sampling point SM2 Trichloroacetic Acid 2452 EPA method 552.2 Not recorded
Not detected below 1 ug/l Minimum Reporting Level , sample collected Jun 30, 2026 12:05, sampling point SM2 Monobromoacetic Acid 2453 EPA method 552.2 Not recorded
Not detected below 1 ug/l Minimum Reporting Level , sample collected Jun 30, 2026 12:05, sampling point SM2 Dibromoacetic Acid 2454 EPA method 552.2 Not recorded
28 ug/l , sample collected Jun 30, 2026 12:05, sampling point SM2 Total Haloacetic Acids (Haa5) 2456 EPA method 552.2 Jan 1, 2026 – Dec 31, 2026
41 ug/l , sample collected Jun 30, 2026 12:05, sampling point SM2 Chloroform 2941 EPA method 524.2 Not recorded
Not detected below 0.5 ug/l Minimum Reporting Level , sample collected Jun 30, 2026 12:05, sampling point SM2 Bromoform 2942 EPA method 524.2 Not recorded
14 ug/l , sample collected Jun 30, 2026 12:05, sampling point SM2 Bromodichloromethane 2943 EPA method 524.2 Not recorded
4.6 ug/l , sample collected Jun 30, 2026 12:05, sampling point SM2 Dibromochloromethane 2944 EPA method 524.2 Not recorded
59.6 ug/l , sample collected Jun 30, 2026 12:05, sampling point SM2 TTHM 2950 EPA method 524.2 Jan 1, 2026 – Dec 31, 2026
Collected
Sep 10, 2025 12:10
Sampling point
SM2 Location withheld
Sample type
Routine
Lab sample
HA-250911-002
Laboratory
MSDH Lab
33.9 ug/l , sample collected Sep 10, 2025 12:10, sampling point SM2 Total Haloacetic Acids (Haa5) 2456 EPA method 552.2 Not recorded
Collected
Sep 10, 2025 12:35
Sampling point
SM1 Location withheld
Sample type
Routine
Lab sample
HA-250911-001
Laboratory
MSDH Lab
27.8 ug/l , sample collected Sep 10, 2025 12:35, sampling point SM1 Total Haloacetic Acids (Haa5) 2456 EPA method 552.2 Not recorded
Collected
Sep 10, 2025 12:10
Sampling point
SM2 Location withheld
Sample type
Routine
Lab sample
TH-250911-002
Laboratory
MSDH Lab
68 ug/l , sample collected Sep 10, 2025 12:10, sampling point SM2 TTHM 2950 EPA method 524.2 Not recorded
Collected
Sep 10, 2025 12:35
Sampling point
SM1 Location withheld
Sample type
Routine
Lab sample
TH-250911-001
Laboratory
MSDH Lab
53.3 ug/l , sample collected Sep 10, 2025 12:35, sampling point SM1 TTHM 2950 EPA method 524.2 Not recorded
Collected
Jun 18, 2025 13:00
Sampling point
TF105 Treatment Plant T105
Sample type
Routine
Lab sample
CN-250619-005
Laboratory
MSDH Lab
Not detected below 0.015 mg/l Minimum Reporting Level , sample collected Jun 18, 2025 13:00, sampling point TF105 Cyanide 1024 EPA method QC10204001X Jan 1, 2023 – Dec 31, 2025

Routine (10).