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.
| 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 141–150 of 284 samples, newest first — collected May 21, 2012 to August 8, 2012. 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.
| Result | Analyte | Monitoring period |
|---|---|---|
|
||
| Not detected below 0.0005 mg/l Minimum Reporting Level , sample collected Aug 8, 2012 14:30, sampling point TF101 | Combined Uranium 4006 EPA method 200.8 | Jul 1, 2012 – Sep 30, 2012 |
|
||
| 0.0029 mg/l , sample collected Jul 12, 2012 06:00, sampling point DS000 | Copper, Free 1022 EPA method 200.8 | Jan 1, 2012 – Dec 31, 2012 |
| Not detected below 0.0005 mg/l Minimum Reporting Level , sample collected Jul 12, 2012 06:00, sampling point DS000 | Lead 1030 EPA method 200.8 | Jan 1, 2012 – Dec 31, 2012 |
|
||
| 0.0127 mg/l , sample collected Jul 12, 2012 07:00, sampling point DS000 | Copper, Free 1022 EPA method 200.8 | Jan 1, 2012 – Dec 31, 2012 |
| Not detected below 0.0005 mg/l Minimum Reporting Level , sample collected Jul 12, 2012 07:00, sampling point DS000 | Lead 1030 EPA method 200.8 | Jan 1, 2012 – Dec 31, 2012 |
|
||
| 0.0023 mg/l , sample collected Jul 12, 2012 07:00, sampling point DS000 | Copper, Free 1022 EPA method 200.8 | Jan 1, 2012 – Dec 31, 2012 |
| Not detected below 0.0005 mg/l Minimum Reporting Level , sample collected Jul 12, 2012 07:00, sampling point DS000 | Lead 1030 EPA method 200.8 | Jan 1, 2012 – Dec 31, 2012 |
|
||
| 0.0148 mg/l , sample collected Jul 12, 2012 08:00, sampling point DS000 | Copper, Free 1022 EPA method 200.8 | Jan 1, 2012 – Dec 31, 2012 |
| Not detected below 0.0005 mg/l Minimum Reporting Level , sample collected Jul 12, 2012 08:00, sampling point DS000 | Lead 1030 EPA method 200.8 | Jan 1, 2012 – Dec 31, 2012 |
|
||
| 0.3129 mg/l , sample collected Jul 12, 2012 06:30, sampling point DS000 | Copper, Free 1022 EPA method 200.8 | Jan 1, 2012 – Dec 31, 2012 |
| Not detected below 0.0005 mg/l Minimum Reporting Level , sample collected Jul 12, 2012 06:30, sampling point DS000 | Lead 1030 EPA method 200.8 | Jan 1, 2012 – Dec 31, 2012 |
|
||
| 0.5 pci/l , sample collected May 21, 2012 12:30, sampling point TF101 | Gross Alpha, Incl. Radon & U 4002 EPA method 00-02 | Not recorded |
| 0.6 pci/l , sample collected May 21, 2012 12:30, sampling point TF101 | Combined Radium (-226 & -228) 4010 | Not recorded |
| Not detected below 0.23 pci/l Minimum Reporting Level , sample collected May 21, 2012 12:30, sampling point TF101 | Radium-226 4020 EPA method 903.1 | Apr 1, 2012 – Jun 30, 2012 |
| 0.6 pci/l , sample collected May 21, 2012 12:30, sampling point TF101 | Radium-228 4030 EPA method 904.0 | Apr 1, 2012 – Jun 30, 2012 |
|
||
| Not detected below 0.37 pci/l Minimum Reporting Level , sample collected May 21, 2012 13:05, sampling point TF102 | Gross Alpha, Incl. Radon & U 4002 EPA method 00-02 | Not recorded |
| Not detected below 0.47 pci/l Minimum Reporting Level , sample collected May 21, 2012 13:05, sampling point TF102 | Combined Radium (-226 & -228) 4010 | Not recorded |
| Not detected below 0.251 pci/l Minimum Reporting Level , sample collected May 21, 2012 13:05, sampling point TF102 | Radium-226 4020 EPA method 903.1 | Apr 1, 2012 – Jun 30, 2012 |
| Not detected below 0.47 pci/l Minimum Reporting Level , sample collected May 21, 2012 13:05, sampling point TF102 | Radium-228 4030 EPA method 904.0 | Apr 1, 2012 – Jun 30, 2012 |
|
||
| 0.7 pci/l , sample collected May 21, 2012 12:45, sampling point TF103 | Gross Alpha, Incl. Radon & U 4002 EPA method 00-02 | Not recorded |
| Not detected below 0.42 pci/l Minimum Reporting Level , sample collected May 21, 2012 12:45, sampling point TF103 | Combined Radium (-226 & -228) 4010 | Not recorded |
| Not detected below 0.265 pci/l Minimum Reporting Level , sample collected May 21, 2012 12:45, sampling point TF103 | Radium-226 4020 EPA method 903.1 | Apr 1, 2012 – Jun 30, 2012 |
| Not detected below 0.42 pci/l Minimum Reporting Level , sample collected May 21, 2012 12:45, sampling point TF103 | Radium-228 4030 EPA method 904.0 | Apr 1, 2012 – Jun 30, 2012 |
|
||
| Not detected below 0.0005 mg/l Minimum Reporting Level , sample collected May 21, 2012 12:30, sampling point TF101 | Combined Uranium 4006 EPA method 200.8 | Apr 1, 2012 – Jun 30, 2012 |
-
- Collected
- Aug 8, 2012 14:30
- Sampling point
- TF101 Treatment Plant T101
- Sample type
- Routine
- Lab sample
- 120809-033RU
- Laboratory
- MSDH Lab
- Monitoring period
- Jul 1, 2012 – Sep 30, 2012
-
Combined Uranium 4006 EPA method 200.8
- Result
- Not detected below 0.0005 mg/l Minimum Reporting Level
-
- Collected
- Jul 12, 2012 06:00
- Sampling point
- DS000 Distribution
- Sample type
- Routine
- Lab sample
- 120713-070PB
- Laboratory
- MSDH Lab
- Monitoring period
- Jan 1, 2012 – Dec 31, 2012
-
Copper, Free 1022 EPA method 200.8
- Result
- 0.0029 mg/l
-
Lead 1030 EPA method 200.8
- Result
- Not detected below 0.0005 mg/l Minimum Reporting Level
-
- Collected
- Jul 12, 2012 07:00
- Sampling point
- DS000 Distribution
- Sample type
- Routine
- Lab sample
- 120713-069PB
- Laboratory
- MSDH Lab
- Monitoring period
- Jan 1, 2012 – Dec 31, 2012
-
Copper, Free 1022 EPA method 200.8
- Result
- 0.0127 mg/l
-
Lead 1030 EPA method 200.8
- Result
- Not detected below 0.0005 mg/l Minimum Reporting Level
-
- Collected
- Jul 12, 2012 07:00
- Sampling point
- DS000 Distribution
- Sample type
- Routine
- Lab sample
- 120713-068PB
- Laboratory
- MSDH Lab
- Monitoring period
- Jan 1, 2012 – Dec 31, 2012
-
Copper, Free 1022 EPA method 200.8
- Result
- 0.0023 mg/l
-
Lead 1030 EPA method 200.8
- Result
- Not detected below 0.0005 mg/l Minimum Reporting Level
-
- Collected
- Jul 12, 2012 08:00
- Sampling point
- DS000 Distribution
- Sample type
- Routine
- Lab sample
- 120713-067PB
- Laboratory
- MSDH Lab
- Monitoring period
- Jan 1, 2012 – Dec 31, 2012
-
Copper, Free 1022 EPA method 200.8
- Result
- 0.0148 mg/l
-
Lead 1030 EPA method 200.8
- Result
- Not detected below 0.0005 mg/l Minimum Reporting Level
-
- Collected
- Jul 12, 2012 06:30
- Sampling point
- DS000 Distribution
- Sample type
- Routine
- Lab sample
- 120713-066PB
- Laboratory
- MSDH Lab
- Monitoring period
- Jan 1, 2012 – Dec 31, 2012
-
Copper, Free 1022 EPA method 200.8
- Result
- 0.3129 mg/l
-
Lead 1030 EPA method 200.8
- Result
- Not detected below 0.0005 mg/l Minimum Reporting Level
-
- Collected
- May 21, 2012 12:30
- Sampling point
- TF101 Treatment Plant T101
- Sample type
- Routine
- Lab sample
- 120522-126
- Laboratory
- Radiation Safety Engineering
-
Gross Alpha, Incl. Radon & U 4002 EPA method 00-02
- Result
- 0.5 pci/l
- Monitoring period
- Not recorded
-
Combined Radium (-226 & -228) 4010
- Result
- 0.6 pci/l
- Monitoring period
- Not recorded
-
Radium-226 4020 EPA method 903.1
- Result
- Not detected below 0.23 pci/l Minimum Reporting Level
- Monitoring period
- Apr 1, 2012 – Jun 30, 2012
-
Radium-228 4030 EPA method 904.0
- Result
- 0.6 pci/l
- Monitoring period
- Apr 1, 2012 – Jun 30, 2012
-
- Collected
- May 21, 2012 13:05
- Sampling point
- TF102 Treatment Plant T102
- Sample type
- Routine
- Lab sample
- 120522-102
- Laboratory
- Radiation Safety Engineering
-
Gross Alpha, Incl. Radon & U 4002 EPA method 00-02
- Result
- Not detected below 0.37 pci/l Minimum Reporting Level
- Monitoring period
- Not recorded
-
Combined Radium (-226 & -228) 4010
- Result
- Not detected below 0.47 pci/l Minimum Reporting Level
- Monitoring period
- Not recorded
-
Radium-226 4020 EPA method 903.1
- Result
- Not detected below 0.251 pci/l Minimum Reporting Level
- Monitoring period
- Apr 1, 2012 – Jun 30, 2012
-
Radium-228 4030 EPA method 904.0
- Result
- Not detected below 0.47 pci/l Minimum Reporting Level
- Monitoring period
- Apr 1, 2012 – Jun 30, 2012
-
- Collected
- May 21, 2012 12:45
- Sampling point
- TF103 Treatment Plant T103
- Sample type
- Routine
- Lab sample
- 120522-103
- Laboratory
- Radiation Safety Engineering
-
Gross Alpha, Incl. Radon & U 4002 EPA method 00-02
- Result
- 0.7 pci/l
- Monitoring period
- Not recorded
-
Combined Radium (-226 & -228) 4010
- Result
- Not detected below 0.42 pci/l Minimum Reporting Level
- Monitoring period
- Not recorded
-
Radium-226 4020 EPA method 903.1
- Result
- Not detected below 0.265 pci/l Minimum Reporting Level
- Monitoring period
- Apr 1, 2012 – Jun 30, 2012
-
Radium-228 4030 EPA method 904.0
- Result
- Not detected below 0.42 pci/l Minimum Reporting Level
- Monitoring period
- Apr 1, 2012 – Jun 30, 2012
-
- Collected
- May 21, 2012 12:30
- Sampling point
- TF101 Treatment Plant T101
- Sample type
- Routine
- Lab sample
- 120522-126RU
- Laboratory
- MSDH Lab
- Monitoring period
- Apr 1, 2012 – Jun 30, 2012
-
Combined Uranium 4006 EPA method 200.8
- Result
- Not detected below 0.0005 mg/l Minimum Reporting Level
Routine (10).