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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 261–270 of 284 samples, newest first — collected June 16, 2004 to September 27, 2004. The summary above covers all 284.

58 results from the 10 samples listed here: 7 detected, 51 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.

Units in this table

Toluene is recorded on this page in ug/l and mg/l. 1 mg/l = 1,000 ug/l.

Chemical and radiological sample results for Lake Arrowhead, every result from 261 to 270 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
Sep 27, 2004
Sampling point
DS000 Distribution
Sample type
Routine
Lab sample
040928-032PB
Laboratory
MSDH Lab
0.03 mg/l , sample collected Sep 27, 2004, sampling point DS000 Copper, Free 1022 EPA method 200.8 Jan 1, 2004 – Dec 31, 2004
Not detected below 0.0005 mg/l Minimum Reporting Level , sample collected Sep 27, 2004, sampling point DS000 Lead 1030 EPA method 200.8 Jan 1, 2004 – Dec 31, 2004
Collected
Sep 27, 2004
Sampling point
DS000 Distribution
Sample type
Routine
Lab sample
040928-039PB
Laboratory
MSDH Lab
0.0035 mg/l , sample collected Sep 27, 2004, sampling point DS000 Copper, Free 1022 EPA method 200.8 Jan 1, 2004 – Dec 31, 2004
0.0011 mg/l , sample collected Sep 27, 2004, sampling point DS000 Lead 1030 EPA method 200.8 Jan 1, 2004 – Dec 31, 2004
Collected
Sep 27, 2004
Sampling point
DS000 Distribution
Sample type
Routine
Lab sample
040928-038PB
Laboratory
MSDH Lab
0.0016 mg/l , sample collected Sep 27, 2004, sampling point DS000 Copper, Free 1022 EPA method 200.8 Jan 1, 2004 – Dec 31, 2004
Not detected below 0.0005 mg/l Minimum Reporting Level , sample collected Sep 27, 2004, sampling point DS000 Lead 1030 EPA method 200.8 Jan 1, 2004 – Dec 31, 2004
Collected
Sep 27, 2004
Sampling point
DS000 Distribution
Sample type
Routine
Lab sample
040928-040PB
Laboratory
MSDH Lab
0.0016 mg/l , sample collected Sep 27, 2004, sampling point DS000 Copper, Free 1022 EPA method 200.8 Jan 1, 2004 – Dec 31, 2004
Not detected below 0.0005 mg/l Minimum Reporting Level , sample collected Sep 27, 2004, sampling point DS000 Lead 1030 EPA method 200.8 Jan 1, 2004 – Dec 31, 2004
Collected
Sep 22, 2004
Sampling point
TF103 Treatment Plant T103
Sample type
Routine
Lab sample
040923-002VO
Laboratory
MSDH Lab
Not detected below 0.0005 mg/l Method Detection Limit , sample collected Sep 22, 2004, sampling point TF103 1,2,4-Trichlorobenzene 2378 EPA method 524.2 Jul 1, 2004 – Sep 30, 2004
Not detected below 0.0005 mg/l Method Detection Limit , sample collected Sep 22, 2004, sampling point TF103 Cis-1,2-Dichloroethylene 2380 EPA method 524.2 Jul 1, 2004 – Sep 30, 2004
Not detected below 0.0005 mg/l Method Detection Limit , sample collected Sep 22, 2004, sampling point TF103 Xylenes, Total 2955 EPA method 524.2 Jul 1, 2004 – Sep 30, 2004
Not detected below 0.0005 mg/l Method Detection Limit , sample collected Sep 22, 2004, sampling point TF103 Dichloromethane 2964 EPA method 524.2 Jul 1, 2004 – Sep 30, 2004
Not detected below 0.0005 mg/l Method Detection Limit , sample collected Sep 22, 2004, sampling point TF103 O-Dichlorobenzene 2968 EPA method 524.2 Jul 1, 2004 – Sep 30, 2004
Not detected below 0.0005 mg/l Method Detection Limit , sample collected Sep 22, 2004, sampling point TF103 P-Dichlorobenzene 2969 EPA method 524.2 Jul 1, 2004 – Sep 30, 2004
Not detected below 0.0005 mg/l Method Detection Limit , sample collected Sep 22, 2004, sampling point TF103 Vinyl Chloride 2976 EPA method 524.2 Jul 1, 2004 – Sep 30, 2004
Not detected below 0.0005 mg/l Method Detection Limit , sample collected Sep 22, 2004, sampling point TF103 1,1-Dichloroethylene 2977 EPA method 524.2 Jul 1, 2004 – Sep 30, 2004
Not detected below 0.0005 mg/l Method Detection Limit , sample collected Sep 22, 2004, sampling point TF103 Trans-1,2-Dichloroethylene 2979 EPA method 524.2 Jul 1, 2004 – Sep 30, 2004
Not detected below 0.0005 mg/l Method Detection Limit , sample collected Sep 22, 2004, sampling point TF103 1,2-Dichloroethane 2980 EPA method 524.2 Jul 1, 2004 – Sep 30, 2004
Not detected below 0.0005 mg/l Method Detection Limit , sample collected Sep 22, 2004, sampling point TF103 1,1,1-Trichloroethane 2981 EPA method 524.2 Jul 1, 2004 – Sep 30, 2004
Not detected below 0.0005 mg/l Method Detection Limit , sample collected Sep 22, 2004, sampling point TF103 Carbon Tetrachloride 2982 EPA method 524.2 Jul 1, 2004 – Sep 30, 2004
Not detected below 0.0005 mg/l Method Detection Limit , sample collected Sep 22, 2004, sampling point TF103 1,2-Dichloropropane 2983 EPA method 524.2 Jul 1, 2004 – Sep 30, 2004
Not detected below 0.0005 mg/l Method Detection Limit , sample collected Sep 22, 2004, sampling point TF103 Trichloroethylene 2984 EPA method 524.2 Jul 1, 2004 – Sep 30, 2004
Not detected below 0.0005 mg/l Method Detection Limit , sample collected Sep 22, 2004, sampling point TF103 1,1,2-Trichloroethane 2985 EPA method 524.2 Jul 1, 2004 – Sep 30, 2004
Not detected below 0.0005 mg/l Method Detection Limit , sample collected Sep 22, 2004, sampling point TF103 Tetrachloroethylene 2987 EPA method 524.2 Jul 1, 2004 – Sep 30, 2004
Not detected below 0.0005 mg/l Method Detection Limit , sample collected Sep 22, 2004, sampling point TF103 Chlorobenzene 2989 EPA method 524.2 Jul 1, 2004 – Sep 30, 2004
Not detected below 0.0005 mg/l Method Detection Limit , sample collected Sep 22, 2004, sampling point TF103 Benzene 2990 EPA method 524.2 Jul 1, 2004 – Sep 30, 2004
0.604 ug/l , sample collected Sep 22, 2004, sampling point TF103 Toluene 2991 EPA method 524.2 Jul 1, 2004 – Sep 30, 2004
Not detected below 0.0005 mg/l Method Detection Limit , sample collected Sep 22, 2004, sampling point TF103 Ethylbenzene 2992 EPA method 524.2 Jul 1, 2004 – Sep 30, 2004
Not detected below 0.0005 mg/l Method Detection Limit , sample collected Sep 22, 2004, sampling point TF103 Styrene 2996 EPA method 524.2 Jul 1, 2004 – Sep 30, 2004
Collected
Sep 22, 2004
Sampling point
TF102 Treatment Plant T102
Sample type
Routine
Lab sample
040923-001VO
Laboratory
MSDH Lab
Not detected below 0.0005 mg/l Method Detection Limit , sample collected Sep 22, 2004, sampling point TF102 1,2,4-Trichlorobenzene 2378 EPA method 524.2 Jul 1, 2004 – Sep 30, 2004
Not detected below 0.0005 mg/l Method Detection Limit , sample collected Sep 22, 2004, sampling point TF102 Cis-1,2-Dichloroethylene 2380 EPA method 524.2 Jul 1, 2004 – Sep 30, 2004
Not detected below 0.0005 mg/l Method Detection Limit , sample collected Sep 22, 2004, sampling point TF102 Xylenes, Total 2955 EPA method 524.2 Jul 1, 2004 – Sep 30, 2004
Not detected below 0.0005 mg/l Method Detection Limit , sample collected Sep 22, 2004, sampling point TF102 Dichloromethane 2964 EPA method 524.2 Jul 1, 2004 – Sep 30, 2004
Not detected below 0.0005 mg/l Method Detection Limit , sample collected Sep 22, 2004, sampling point TF102 O-Dichlorobenzene 2968 EPA method 524.2 Jul 1, 2004 – Sep 30, 2004
Not detected below 0.0005 mg/l Method Detection Limit , sample collected Sep 22, 2004, sampling point TF102 P-Dichlorobenzene 2969 EPA method 524.2 Jul 1, 2004 – Sep 30, 2004
Not detected below 0.0005 mg/l Method Detection Limit , sample collected Sep 22, 2004, sampling point TF102 Vinyl Chloride 2976 EPA method 524.2 Jul 1, 2004 – Sep 30, 2004
Not detected below 0.0005 mg/l Method Detection Limit , sample collected Sep 22, 2004, sampling point TF102 1,1-Dichloroethylene 2977 EPA method 524.2 Jul 1, 2004 – Sep 30, 2004
Not detected below 0.0005 mg/l Method Detection Limit , sample collected Sep 22, 2004, sampling point TF102 Trans-1,2-Dichloroethylene 2979 EPA method 524.2 Jul 1, 2004 – Sep 30, 2004
Not detected below 0.0005 mg/l Method Detection Limit , sample collected Sep 22, 2004, sampling point TF102 1,2-Dichloroethane 2980 EPA method 524.2 Jul 1, 2004 – Sep 30, 2004
Not detected below 0.0005 mg/l Method Detection Limit , sample collected Sep 22, 2004, sampling point TF102 1,1,1-Trichloroethane 2981 EPA method 524.2 Jul 1, 2004 – Sep 30, 2004
Not detected below 0.0005 mg/l Method Detection Limit , sample collected Sep 22, 2004, sampling point TF102 Carbon Tetrachloride 2982 EPA method 524.2 Jul 1, 2004 – Sep 30, 2004
Not detected below 0.0005 mg/l Method Detection Limit , sample collected Sep 22, 2004, sampling point TF102 1,2-Dichloropropane 2983 EPA method 524.2 Jul 1, 2004 – Sep 30, 2004
Not detected below 0.0005 mg/l Method Detection Limit , sample collected Sep 22, 2004, sampling point TF102 Trichloroethylene 2984 EPA method 524.2 Jul 1, 2004 – Sep 30, 2004
Not detected below 0.0005 mg/l Method Detection Limit , sample collected Sep 22, 2004, sampling point TF102 1,1,2-Trichloroethane 2985 EPA method 524.2 Jul 1, 2004 – Sep 30, 2004
Not detected below 0.0005 mg/l Method Detection Limit , sample collected Sep 22, 2004, sampling point TF102 Tetrachloroethylene 2987 EPA method 524.2 Jul 1, 2004 – Sep 30, 2004
Not detected below 0.0005 mg/l Method Detection Limit , sample collected Sep 22, 2004, sampling point TF102 Chlorobenzene 2989 EPA method 524.2 Jul 1, 2004 – Sep 30, 2004
Not detected below 0.0005 mg/l Method Detection Limit , sample collected Sep 22, 2004, sampling point TF102 Benzene 2990 EPA method 524.2 Jul 1, 2004 – Sep 30, 2004
Not detected below 0.0005 mg/l Method Detection Limit , sample collected Sep 22, 2004, sampling point TF102 Toluene 2991 EPA method 524.2 Jul 1, 2004 – Sep 30, 2004
Not detected below 0.0005 mg/l Method Detection Limit , sample collected Sep 22, 2004, sampling point TF102 Ethylbenzene 2992 EPA method 524.2 Jul 1, 2004 – Sep 30, 2004
Not detected below 0.0005 mg/l Method Detection Limit , sample collected Sep 22, 2004, sampling point TF102 Styrene 2996 EPA method 524.2 Jul 1, 2004 – Sep 30, 2004
Collected
Aug 23, 2004
Sampling point
MRT000 Max. Res. Time
Sample type
Routine
Lab sample
040824-002TH
Laboratory
MSDH Lab
Not detected below 1 ug/l Minimum Reporting Level , sample collected Aug 23, 2004, sampling point MRT000 TTHM 2950 EPA method 524.2 Jan 1, 2004 – Dec 31, 2004
Collected
Aug 23, 2004
Sampling point
MRT000 Max. Res. Time
Sample type
Routine
Lab sample
040824-002HA
Laboratory
MSDH Lab
Not detected below 0.01 mg/l Minimum Reporting Level , sample collected Aug 23, 2004, sampling point MRT000 Total Haloacetic Acids (Haa5) 2456 EPA method 552.2 Jan 1, 2004 – Dec 31, 2004
Collected
Jun 16, 2004
Sampling point
TF104 Treatment Plant T104
Sample type
Routine
Lab sample
040617-117NI
Laboratory
MSDH Lab
Not detected below 0.1 mg/l Minimum Reporting Level , sample collected Jun 16, 2004, sampling point TF104 Nitrate-Nitrite 1038 EPA method 353.2 Not recorded
0.08 mg/l The agency recorded which kind of limit this result was below, but stored 0.000000000 as the limit itself, which is not a level. The type is published and the value is null. What the limit was is not on record. Whether the result was a detection is a separate column: read resultType. , sample collected Jun 16, 2004, sampling point TF104 Nitrate 1040 EPA method 353.2 Not recorded
Not detected below 0.02 mg/l Minimum Reporting Level , sample collected Jun 16, 2004, sampling point TF104 Nitrite 1041 EPA method 353.2 Not recorded
Collected
Jun 16, 2004
Sampling point
TF103 Treatment Plant T103
Sample type
Routine
Lab sample
040617-112NI
Laboratory
MSDH Lab
Not detected below 0.1 mg/l Minimum Reporting Level , sample collected Jun 16, 2004, sampling point TF103 Nitrate-Nitrite 1038 EPA method 353.2 Jan 1, 2004 – Dec 31, 2004
Not detected below 0.08 mg/l Minimum Reporting Level , sample collected Jun 16, 2004, sampling point TF103 Nitrate 1040 EPA method 353.2 Jan 1, 2004 – Dec 31, 2004
Not detected below 0.02 mg/l Minimum Reporting Level , sample collected Jun 16, 2004, sampling point TF103 Nitrite 1041 EPA method 353.2 Jan 1, 2004 – Dec 31, 2004

Routine (10).