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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

MS0730010 , Lake Arrowhead

19 of the 57 analytes this system has been tested for have been detected at least once, across 284 samples on record.

The other 38 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 284 samples on record, detections range from November 5, 2003 to April 2, 2025. These figures cover the whole record.

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 Lake Arrowhead, 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 82 of 83 results Sep 27, 2004 Aug 28, 2023
Lead 1030 Inorganic Chemical 41 of 83 results Sep 27, 2004 Sep 9, 2020
Barium 1010 Inorganic Chemical 29 of 29 results Nov 5, 2003 Apr 2, 2025
Fluoride 1025 Inorganic Chemical 24 of 29 results Nov 5, 2003 Apr 2, 2025
Nitrate 1040 Inorganic Chemical 19 of 64 results Jun 16, 2004 Apr 17, 2024
Nitrate-Nitrite 1038 Inorganic Chemical 16 of 64 results Apr 2, 2012 Apr 17, 2024
Nickel 1036 Inorganic Chemical 14 of 29 results May 29, 2013 Apr 2, 2025
Chromium 1020 Inorganic Chemical 12 of 29 results Nov 16, 2004 Dec 13, 2016
Gross Alpha, Incl. Radon & U 4002 Radionuclide 10 of 15 results Mar 12, 2012 Oct 12, 2012
Sodium 1052 Inorganic Chemical 6 of 6 results Sep 16, 2019 Mar 28, 2023
Combined Radium (-226 & -228) 4010 Radionuclide 5 of 15 results Mar 12, 2012 Oct 12, 2012
Radium-228 4030 Radionuclide 5 of 15 results Mar 12, 2012 Oct 12, 2012
Nitrite 1041 Inorganic Chemical 4 of 64 results Dec 6, 2004 Apr 17, 2024
Sulfate 1055 Inorganic Chemical 4 of 4 results Nov 5, 2003 Mar 29, 2004
TTHM 2950 Organic Chemical 2 of 7 results Sep 20, 2007 Jul 15, 2010
Selenium 1045 Inorganic Chemical 2 of 29 results Mar 29, 2004 Nov 16, 2004
Total Haloacetic Acids (Haa5) 2456 Organic Chemical 1 of 7 results Jul 15, 2010 Jul 15, 2010
Toluene 2991 Organic Chemical 1 of 28 results Sep 22, 2004 Sep 22, 2004
Cadmium 1015 Inorganic Chemical 1 of 29 results Nov 5, 2003 Nov 5, 2003

No date range is applied: this list draws on every sample on record. Show the last two years only.

The most recent samples, result by result

The table below lists 111–120 of 284 samples, newest first — collected June 6, 2013 to June 11, 2014. The summary above covers all 284.

24 results from the 10 samples listed here: 9 detected, 15 not detected. Across the whole record it is 278 of 1,425. A sample is analysed for many analytes at once, so one sample appears on as many rows as it had results.

Chemical and radiological sample results for Lake Arrowhead, every result from 111 to 120 of 284 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
Jun 11, 2014 06:00
Sampling point
DS000 Distribution
Sample type
Routine
Lab sample
140612-108PB
Laboratory
MSDH Lab
0.048 mg/l , sample collected Jun 11, 2014 06:00, sampling point DS000 Copper, Free 1022 EPA method 200.8 Jan 1, 2014 – Dec 31, 2014
0.0015 mg/l , sample collected Jun 11, 2014 06:00, sampling point DS000 Lead 1030 EPA method 200.8 Jan 1, 2014 – Dec 31, 2014
Collected
Jun 11, 2014 00:05
Sampling point
DS000 Distribution
Sample type
Routine
Lab sample
140612-107PB
Laboratory
MSDH Lab
0.0055 mg/l , sample collected Jun 11, 2014 00:05, sampling point DS000 Copper, Free 1022 EPA method 200.8 Jan 1, 2014 – Dec 31, 2014
Not detected below 0.0005 mg/l Minimum Reporting Level , sample collected Jun 11, 2014 00:05, sampling point DS000 Lead 1030 EPA method 200.8 Jan 1, 2014 – Dec 31, 2014
Collected
Jun 10, 2014 07:55
Sampling point
DS000 Distribution
Sample type
Routine
Lab sample
140612-111PB
Laboratory
MSDH Lab
0.0097 mg/l , sample collected Jun 10, 2014 07:55, sampling point DS000 Copper, Free 1022 EPA method 200.8 Jan 1, 2014 – Dec 31, 2014
0.0018 mg/l , sample collected Jun 10, 2014 07:55, sampling point DS000 Lead 1030 EPA method 200.8 Jan 1, 2014 – Dec 31, 2014
Collected
Oct 30, 2013 12:30
Sampling point
MRT000 Max. Res. Time
Sample type
Routine
Lab sample
131031-006TH
Laboratory
MSDH Lab
Not detected below 1 ug/l Minimum Reporting Level , sample collected Oct 30, 2013 12:30, sampling point MRT000 Chloroform 2941 EPA method 524.2 Not recorded
Not detected below 1 ug/l Minimum Reporting Level , sample collected Oct 30, 2013 12:30, sampling point MRT000 Bromoform 2942 EPA method 524.2 Not recorded
Not detected below 1 ug/l Minimum Reporting Level , sample collected Oct 30, 2013 12:30, sampling point MRT000 Bromodichloromethane 2943 EPA method 524.2 Not recorded
Not detected below 1 ug/l Minimum Reporting Level , sample collected Oct 30, 2013 12:30, sampling point MRT000 Dibromochloromethane 2944 EPA method 524.2 Not recorded
Not detected below 4 ug/l Minimum Reporting Level , sample collected Oct 30, 2013 12:30, sampling point MRT000 TTHM 2950 EPA method 524.2 Jan 1, 2011 – Dec 31, 2013
Collected
Oct 30, 2013 12:30
Sampling point
MRT000 Max. Res. Time
Sample type
Routine
Lab sample
131031-006HA
Laboratory
MSDH Lab
Not detected below 0.002 mg/l Minimum Reporting Level , sample collected Oct 30, 2013 12:30, sampling point MRT000 Monochloroacetic Acid 2450 EPA method 552.2 Not recorded
Not detected below 0.001 mg/l Minimum Reporting Level , sample collected Oct 30, 2013 12:30, sampling point MRT000 Dichloroacetic Acid 2451 EPA method 552.2 Not recorded
Not detected below 0.001 mg/l Minimum Reporting Level , sample collected Oct 30, 2013 12:30, sampling point MRT000 Trichloroacetic Acid 2452 EPA method 552.2 Not recorded
Not detected below 0.001 mg/l Minimum Reporting Level , sample collected Oct 30, 2013 12:30, sampling point MRT000 Monobromoacetic Acid 2453 EPA method 552.2 Not recorded
Not detected below 0.001 mg/l Minimum Reporting Level , sample collected Oct 30, 2013 12:30, sampling point MRT000 Dibromoacetic Acid 2454 EPA method 552.2 Not recorded
Not detected below 0.006 mg/l Minimum Reporting Level , sample collected Oct 30, 2013 12:30, sampling point MRT000 Total Haloacetic Acids (Haa5) 2456 Jan 1, 2011 – Dec 31, 2013
Collected
Oct 24, 2013 12:30
Sampling point
TF101 Treatment Plant T101
Sample type
Routine
Lab sample
131024-021CN
Laboratory
MSDH Lab
Not detected below 0.015 mg/l Minimum Reporting Level , sample collected Oct 24, 2013 12:30, sampling point TF101 Cyanide 1024 EPA method QC10204001X Jan 1, 2011 – Dec 31, 2013
Collected
Oct 24, 2013 12:45
Sampling point
TF102 Treatment Plant T102
Sample type
Routine
Lab sample
131024-020CN
Laboratory
MSDH Lab
Not detected below 0.015 mg/l Minimum Reporting Level , sample collected Oct 24, 2013 12:45, sampling point TF102 Cyanide 1024 EPA method QC10204001X Jan 1, 2011 – Dec 31, 2013
Collected
Oct 24, 2013 12:37
Sampling point
TF103 Treatment Plant T103
Sample type
Routine
Lab sample
131024-018CN
Laboratory
MSDH Lab
Not detected below 0.015 mg/l Minimum Reporting Level , sample collected Oct 24, 2013 12:37, sampling point TF103 Cyanide 1024 EPA method QC10204001X Jan 1, 2011 – Dec 31, 2013
Collected
Jun 6, 2013
Sampling point
DS000 Distribution
Sample type
Routine
Lab sample
130607-028PB
Laboratory
MSDH Lab
0.0198 mg/l , sample collected Jun 6, 2013, sampling point DS000 Copper, Free 1022 EPA method 200.8 Jan 1, 2013 – Dec 31, 2013
0.0176 mg/l , sample collected Jun 6, 2013, sampling point DS000 Lead 1030 EPA method 200.8 Jan 1, 2013 – Dec 31, 2013
Collected
Jun 6, 2013 05:00
Sampling point
DS000 Distribution
Sample type
Routine
Lab sample
130607-027PB
Laboratory
MSDH Lab
0.0029 mg/l , sample collected Jun 6, 2013 05:00, sampling point DS000 Copper, Free 1022 EPA method 200.8 Jan 1, 2013 – Dec 31, 2013
0.0011 mg/l , sample collected Jun 6, 2013 05:00, sampling point DS000 Lead 1030 EPA method 200.8 Jan 1, 2013 – Dec 31, 2013

Routine (10).