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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

MS0140010 , Town of Lyon

26 of the 58 analytes this system has been tested for have been detected at least once, across 379 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 379 samples on record, detections range from September 28, 1993 to September 30, 2025. 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 Town of Lyon, 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
TTHM 2950 Organic Chemical 106 of 112 results Sep 15, 2004 Sep 24, 2025
Total Haloacetic Acids (Haa5) 2456 Organic Chemical 100 of 107 results Sep 15, 2004 Sep 24, 2025
Copper, Free 1022 Inorganic Chemical 76 of 77 results Sep 28, 1993 Sep 30, 2025
Bromodichloromethane 2943 Organic Chemical 75 of 79 results May 16, 2006 May 19, 2020
Dibromochloromethane 2944 Organic Chemical 75 of 79 results May 16, 2006 May 19, 2020
Bromoform 2942 Organic Chemical 74 of 79 results May 16, 2006 May 19, 2020
Dibromoacetic Acid 2454 Organic Chemical 72 of 75 results Oct 11, 2007 May 19, 2020
Chloroform 2941 Organic Chemical 72 of 79 results May 16, 2006 May 19, 2020
Trichloroacetic Acid 2452 Organic Chemical 66 of 75 results Oct 11, 2007 May 19, 2020
Dichloroacetic Acid 2451 Organic Chemical 63 of 75 results Apr 28, 2008 May 19, 2020
Lead 1030 Inorganic Chemical 52 of 77 results Sep 28, 1993 Sep 30, 2025
Monobromoacetic Acid 2453 Organic Chemical 35 of 75 results Jan 29, 2008 Aug 15, 2019
Monochloroacetic Acid 2450 Organic Chemical 13 of 75 results Nov 18, 2009 May 19, 2020
Arsenic 1005 Inorganic Chemical 12 of 12 results Apr 9, 2002 Mar 12, 2025
Barium 1010 Inorganic Chemical 12 of 12 results Apr 9, 2002 Mar 12, 2025
Fluoride 1025 Inorganic Chemical 12 of 12 results Apr 9, 2002 Mar 12, 2025
Selenium 1045 Inorganic Chemical 12 of 12 results Apr 9, 2002 Mar 12, 2025
Chromium 1020 Inorganic Chemical 8 of 12 results Apr 9, 2002 May 11, 2022
Xylenes, Total 2955 Organic Chemical 8 of 33 results Jan 12, 2004 Apr 20, 2021
Thallium, Total 1085 Inorganic Chemical 2 of 12 results Feb 28, 2005 Apr 22, 2020
Gross Alpha Particle Activity 4109 Radionuclide 2 of 6 results Sep 28, 2011 Sep 12, 2012
Nitrite 1041 Inorganic Chemical 1 of 20 results Jan 10, 2022 Jan 10, 2022
Sodium 1052 Inorganic Chemical 1 of 1 result Sep 25, 2019 Sep 25, 2019
Gross Alpha, Excl. Radon & U 4000 Radionuclide 1 of 2 results Sep 28, 2011 Sep 28, 2011
Nickel 1036 Inorganic Chemical 1 of 12 results Mar 24, 2008 Mar 24, 2008
Mercury 1035 Inorganic Chemical 1 of 12 results Feb 28, 2005 Feb 28, 2005

Showing samples collected between September 25, 2024 and September 25, 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 24 samples, newest first — collected September 24, 2025 to December 17, 2025. The summary above covers all 24.

15 results from the 10 samples listed here: 14 detected, 1 not detected. Across the whole record it is 952 of 1,981. 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 5 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 Town of Lyon, every result from 1 to 10 of 24 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
Dec 17, 2025 07:04
Sampling point
TF101 Treatment Plant T101
Sample type
Routine
Lab sample
CN-251218-001
Laboratory
MSDH Lab
Not detected below 0.015 mg/l Minimum Reporting Level , sample collected Dec 17, 2025 07:04, sampling point TF101 Cyanide 1024 EPA method QC10204001X Jan 1, 2023 – Dec 31, 2025
Collected
Sep 30, 2025 06:08
Sampling point
LC008 Location withheld
Sample type
Routine
Lab sample
PB-251002-085
Laboratory
MSDH Lab
0.458 mg/l , sample collected Sep 30, 2025 06:08, sampling point LC008 Copper, Free 1022 EPA method 200.8 Jan 1, 2023 – Dec 31, 2025
1.3 ug/l , sample collected Sep 30, 2025 06:08, sampling point LC008 Lead 1030 EPA method 200.8 Jan 1, 2023 – Dec 31, 2025
Collected
Sep 30, 2025 06:13
Sampling point
LC002 Location withheld
Sample type
Routine
Lab sample
PB-251002-084
Laboratory
MSDH Lab
0.101 mg/l , sample collected Sep 30, 2025 06:13, sampling point LC002 Copper, Free 1022 EPA method 200.8 Jan 1, 2023 – Dec 31, 2025
2.5 ug/l , sample collected Sep 30, 2025 06:13, sampling point LC002 Lead 1030 EPA method 200.8 Jan 1, 2023 – Dec 31, 2025
Collected
Sep 30, 2025 06:21
Sampling point
TC0001 Outside Faucet
Sample type
Routine
Lab sample
PB-251002-083
Laboratory
MSDH Lab
0.354 mg/l , sample collected Sep 30, 2025 06:21, sampling point TC0001 Copper, Free 1022 EPA method 200.8 Jan 1, 2023 – Dec 31, 2025
1 ug/l , sample collected Sep 30, 2025 06:21, sampling point TC0001 Lead 1030 EPA method 200.8 Jan 1, 2023 – Dec 31, 2025
Collected
Sep 30, 2025 06:28
Sampling point
TC0006 Outside Faucet
Sample type
Routine
Lab sample
PB-251002-082
Laboratory
MSDH Lab
0.117 mg/l , sample collected Sep 30, 2025 06:28, sampling point TC0006 Copper, Free 1022 EPA method 200.8 Jan 1, 2023 – Dec 31, 2025
1 ug/l , sample collected Sep 30, 2025 06:28, sampling point TC0006 Lead 1030 EPA method 200.8 Jan 1, 2023 – Dec 31, 2025
Collected
Sep 30, 2025 06:34
Sampling point
LC009 Location withheld
Sample type
Routine
Lab sample
PB-251002-081
Laboratory
MSDH Lab
0.0781 mg/l , sample collected Sep 30, 2025 06:34, sampling point LC009 Copper, Free 1022 EPA method 200.8 Jan 1, 2023 – Dec 31, 2025
0.9 ug/l , sample collected Sep 30, 2025 06:34, sampling point LC009 Lead 1030 EPA method 200.8 Jan 1, 2023 – Dec 31, 2025
Collected
Sep 24, 2025 07:53
Sampling point
SM2 Location withheld
Sample type
Routine
Lab sample
HA-250925-002
Laboratory
MSDH Lab
10.9 ug/l , sample collected Sep 24, 2025 07:53, sampling point SM2 Total Haloacetic Acids (Haa5) 2456 EPA method 552.2 Jul 1, 2025 – Sep 30, 2025
Collected
Sep 24, 2025 07:34
Sampling point
SM1 Location withheld
Sample type
Routine
Lab sample
HA-250925-001
Laboratory
MSDH Lab
9.01 ug/l , sample collected Sep 24, 2025 07:34, sampling point SM1 Total Haloacetic Acids (Haa5) 2456 EPA method 552.2 Jul 1, 2025 – Sep 30, 2025
Collected
Sep 24, 2025 07:29
Sampling point
SM1 Location withheld
Sample type
Routine
Lab sample
TH-250925-001
Laboratory
MSDH Lab
25.9 ug/l , sample collected Sep 24, 2025 07:29, sampling point SM1 TTHM 2950 EPA method 524.2 Jul 1, 2025 – Sep 30, 2025
Collected
Sep 24, 2025 07:48
Sampling point
SM2 Location withheld
Sample type
Routine
Lab sample
TH-250925-002
Laboratory
MSDH Lab
26.4 ug/l , sample collected Sep 24, 2025 07:48, sampling point SM2 TTHM 2950 EPA method 524.2 Jul 1, 2025 – Sep 30, 2025

Routine (10).