The Power of Information

National Drinking Water Database


California Water Service - Stockton Utilities - San Jose, CA


Serves 155,670 people

Arsenic (total)

Arsenic contaminates drinking water due to mining runoff, erosion of natural deposits, emissions from glass and electronics processing and the use of arsenical compounds as wood preservatives and pesticides.
 
This Drinking Water System
Test Days Exceeding Health GuidelinesDefinition of what this is
155 days
Test Days Exceeding Legal LimitsNumber of days in which the samples taken in that day exceed the Maximum Contaminant Level (Depending on the contaminant and its MCL, that may or may not trigger an MCL violation. Some MCLs are based on averages spanning several months to a year)
99 days
Test DaysNumber of days in which this chemical has reported results in the data we received from the State
156 days
Tests ConductedNumber of individual tests done for this contaminant
468 tests

Testing Summary

ContaminantAverage/
Maximum
Result
Health Limit
Exceeded
Legal Limit
Exceeded

Testing History

-Tested      -Detected      -Over Health Guidelines      -Over Legal Limit*
Arsenic (total)Arsenic contaminates drinking water due to mining runoff, erosion of natural deposits, emissions from glass and electronics processing and the use of arsenical compounds as wood preservatives and pesticides.12.13 ppb
25 ppb
Yes
MCLGA non-enforceable health goal that is set at a level at which no known or anticipated adverse effect on the health of persons occurs and which allows an adequate margin of safety. Source: U.S. Environmental Protection Agency.: 0 ppb
Yes
10 ppb
NOTE: Each dot in the above graph represents one month.
* Water utilities are noted as exceeding the legal limit if any test is above the maximum contaminant level (MCL). Most MCLs are based on annual averages so exceeding the MCL for one test does not necessarily indicate that the system is out of compliance.

Health Based and Legal Limits for Arsenic (total)

Health Based Limits for Arsenic (total)

StandardDescriptionLevel
Maximum Contaminant Limit Goal (MCLG)A non-enforceable health goal that is set at a level at which no known or anticipated adverse effect on the health of persons occurs and which allows an adequate margin of safety. Source: U.S. Environmental Protection Agency.0 ppb
California Public Health GoalsDefined by the State of California Office of Environmental Health Hazard Assessment (OEHHA) as the level of contaminant that is allowed in drinking water. For acutely toxic substances, levels are set at which scientific evidence indicates that no known or anticipated adverse effects on health will occur, plus an adequate margin-of safety. PHGs for carcinogens or other substances which can cause chronic disease shall be based solely on health effects without regard to cost impacts and shall be set at levels which OEHHA has determined do not pose any significant risk to health.<0.01 ppb
EPA Human Health Water Quality CriteriaWater quality criteria set by the US EPA provide guidance for states and tribes authorized to establish water quality standards under the Clean Water Act (CWA) to protect human health. These are non-enforceable standards based upon exposure by both drinking water and the contribution of water contamination to other consumed foods. Source: U.S. Environmental Protection Agency.0.02 ppb
One in one million (10-6) Cancer RiskThe concentration of a chemical in drinking water corresponding to an excess estimated lifetime cancer risk of 1 in 1,000,000. Source: U.S. Environmental Protection Agency.0.02 ppb
One in ten thousand (10-4) Cancer RiskThe concentration of a chemical in drinking water corresponding to an excess estimated lifetime cancer risk of 1 in 10,000. Source: U.S. Environmental Protection Agency.2 ppb
Maximum Contaminant Limit (MCL)The enforceable standard which defines the highest level of a contaminant that is allowed in drinking water. MCLs are set as close to health-based limits (Maximum Contaminant Level Goals, or MCLGs) as feasible using the best available analytical and treatment technologies and taking cost into consideration. Source: U.S. Environmental Protection Agency.10 ppb
Drinking Water Equivalent LevelA lifetime exposure concentration protective of adverse, noncarcinogenic health effects, that assumes all of the exposure to a contaminant is from drinking water. Source: U.S. Environmental Protection Agency.10 ppb

Testing Results

Testing DateAverage
Result
Samples taken that dayNumber of Non-DetectsRange of Results
2009-03-1815.38 ppb601.85 to 22.24 ppb
2009-03-1215.6 ppb604.9 to 22.28 ppb
2009-03-0416.4 ppb606.51 to 23.76 ppb
2009-02-2515.91 ppb606.93 to 21.91 ppb
2009-02-1816.13 ppb607.09 to 21.91 ppb
2009-02-1116.02 ppb604.27 to 22.46 ppb
2009-02-0415.47 ppb505.5 to 22.74 ppb
2009-01-2815.27 ppb505.58 to 22.59 ppb
2009-01-2215.5 ppb400.32 to 21.86 ppb
2009-01-208.14 ppb108.14 ppb
2009-01-157.78 ppb107.78 ppb
2009-01-1417.99 ppb407.96 to 23.75 ppb
2009-01-0614.83 ppb303.45 to 21.81 ppb
2008-12-3016.5 ppb405.05 to 21.84 ppb
2008-12-0816.24 ppb407.47 to 19.59 ppb
2008-11-1917.67 ppb3016 to 19 ppb
2008-11-170 ppb110 ppb
2008-10-0616.04 ppb501.85 to 20.56 ppb
2008-09-1515.91 ppb501.08 to 21.3 ppb
2008-08-0414.92 ppb601.82 to 22.87 ppb
2008-07-285.3 ppb105.3 ppb
2008-07-0818.63 ppb2018.29 to 18.97 ppb
2008-07-0715.11 ppb302.12 to 24.2 ppb
2008-06-3025 ppb1025 ppb
2008-06-0515.28 ppb500.73 to 20.39 ppb
2008-06-0310.85 ppb204.05 to 17.64 ppb
2008-05-195.9 ppb105.9 ppb
2008-05-0610.51 ppb601.21 to 20.31 ppb
2008-04-0814.98 ppb306.41 to 20.09 ppb
2008-04-075.14 ppb200.25 to 10.03 ppb
2008-03-0413.65 ppb401.56 to 22.31 ppb
2008-02-0510.43 ppb500.35 to 20.08 ppb
2008-01-1412.83 ppb401.59 to 20.1 ppb
2007-12-1012.93 ppb400.6 to 19.4 ppb
2007-11-066.12 ppb204.79 to 7.45 ppb
2007-11-0513.43 ppb400.91 to 18.66 ppb
2007-10-165.25 ppb105.25 ppb
2007-10-0914.78 ppb502.09 to 19.86 ppb
2007-09-1914 ppb1014 ppb
2007-09-1715.52 ppb1015.52 ppb
2007-09-1111.2 ppb306.29 to 20.53 ppb
2007-09-1013.08 ppb401.76 to 18.57 ppb
2007-08-3012 ppb1012 ppb
2007-08-0612.91 ppb401.37 to 19.39 ppb
2007-07-1110.04 ppb400.99 to 19.22 ppb
2007-06-0416.01 ppb400.56 to 23.09 ppb
2007-05-1414.64 ppb401.7 to 21.74 ppb
2007-04-0914.52 ppb401.61 to 21.3 ppb
2007-03-0515.15 ppb402.69 to 22.69 ppb
2007-02-0515.04 ppb403.44 to 21.96 ppb
2007-01-0815.54 ppb400.44 to 23.79 ppb
2006-12-0615.7 ppb401.95 to 24.11 ppb
2006-11-146.22 ppb106.22 ppb
2006-11-0813.23 ppb602.31 to 20.19 ppb
2006-11-0115.34 ppb502.7 to 21 ppb
2006-10-2513.4 ppb510 to 18 ppb
2006-10-1815.96 ppb502.8 to 22 ppb
2006-10-176.5 ppb106.5 ppb
2006-10-1113.4 ppb510 to 19 ppb
2006-10-0414.84 ppb502.2 to 20 ppb
2006-09-2715.26 ppb502.3 to 21 ppb
2006-09-2015.7 ppb503.5 to 22 ppb
2006-09-1316.2 ppb505 to 22 ppb
2006-09-0614.62 ppb503.1 to 20 ppb
2006-08-3013.82 ppb504.1 to 21 ppb
2006-08-2314.4 ppb510 to 21 ppb
2006-08-1617.04 ppb503.2 to 23 ppb
2006-08-0916.26 ppb503.3 to 24 ppb
2006-08-0217.56 ppb502.8 to 25 ppb
2006-07-2617.02 ppb504.1 to 25 ppb
2006-07-2513 ppb204 to 22 ppb
2006-07-2413.25 ppb204.5 to 22 ppb
2006-07-2112.95 ppb203.9 to 22 ppb
2006-07-2016.8 ppb510 to 26 ppb
2006-07-1417.25 ppb403 to 26 ppb
2006-07-0615.95 ppb402.8 to 24 ppb
2006-06-2814.28 ppb403.1 to 20 ppb
2006-06-2114.4 ppb402.6 to 22 ppb
2006-06-2011 ppb210 to 22 ppb
2006-06-1912.1 ppb203.2 to 21 ppb
2006-06-1612.15 ppb203.3 to 21 ppb
2006-06-157.13 ppb310 to 16 ppb
2006-06-1410 ppb310 to 15 ppb
2006-06-138 ppb210 to 16 ppb
2006-06-125.5 ppb210 to 11 ppb
2006-06-096 ppb210 to 12 ppb
2006-06-078 ppb210 to 16 ppb
2006-06-069 ppb210 to 18 ppb
2006-06-058 ppb210 to 16 ppb
2006-06-028.5 ppb210 to 17 ppb
2006-05-317.5 ppb210 to 15 ppb
2006-05-307 ppb210 to 14 ppb
2006-05-2614 ppb1014 ppb
2006-05-255.5 ppb210 to 11 ppb
2006-05-246 ppb210 to 12 ppb
2006-05-237 ppb210 to 14 ppb
2006-05-222.15 ppb210 to 4.3 ppb
2006-05-109.95 ppb304.39 to 13.64 ppb
2006-05-037.7 ppb107.7 ppb
2006-05-026.4 ppb106.4 ppb
2006-02-1218.25 ppb4013 to 22 ppb
2006-02-097.48 ppb107.48 ppb
2006-02-0210 ppb1010 ppb
2005-12-1218.25 ppb4013 to 22 ppb
2005-11-1017.5 ppb4012 to 21 ppb
2005-11-0113.64 ppb205.83 to 21.46 ppb
2005-10-0618 ppb5012 to 21 ppb
2005-09-0817.2 ppb5011 to 20 ppb
2005-08-2218.29 ppb5011.96 to 22.2 ppb
2005-07-2611.09 ppb1011.09 ppb
2005-07-2519.74 ppb4016.52 to 21.19 ppb
2005-07-125.74 ppb304.25 to 7.69 ppb
2005-06-2318.77 ppb4014.56 to 20.43 ppb
2005-06-144.47 ppb204.44 to 4.5 ppb
2005-05-1714.66 ppb1014.66 ppb
2005-05-1513.29 ppb1013.29 ppb
2005-05-1121.36 ppb2020.76 to 21.97 ppb
2005-05-108.28 ppb108.28 ppb
2005-05-0320.08 ppb1020.08 ppb
2005-04-1417.92 ppb5012.8 to 21.64 ppb
2005-03-2814.55 ppb1014.55 ppb
2005-03-2513.5 ppb1013.5 ppb
2005-03-2419.56 ppb1019.56 ppb
2005-03-2321.69 ppb2021.22 to 22.15 ppb
2005-03-154.01 ppb104.01 ppb
2004-12-078.88 ppb304.63 to 14.33 ppb
2004-12-034.54 ppb203.73 to 5.34 ppb
2004-11-2212.14 ppb1012.14 ppb
2004-11-2017.62 ppb1017.62 ppb
2004-11-174.23 ppb203.88 to 4.58 ppb
2004-11-167.83 ppb107.83 ppb
2004-11-156.42 ppb205.99 to 6.86 ppb
2004-10-275.17 ppb105.17 ppb
2004-10-195.33 ppb105.33 ppb
2004-10-187.24 ppb107.24 ppb
2004-10-165.07 ppb204.03 to 6.11 ppb
2004-09-3020 ppb1020 ppb
2004-09-215.67 ppb304.7 to 6.51 ppb
2004-09-2020.72 ppb1020.72 ppb
2004-08-263.88 ppb103.88 ppb
2004-08-2422.23 ppb1022.23 ppb
2004-08-1920.45 ppb2020.32 to 20.58 ppb
2004-08-174.47 ppb104.47 ppb
2004-08-164.88 ppb104.88 ppb
2004-08-128.14 ppb503.77 to 18.85 ppb
2004-07-197.03 ppb405.4 to 8.08 ppb
2004-06-104.49 ppb204.39 to 4.58 ppb
2004-05-284.68 ppb403.48 to 7.1 ppb
2004-05-2518.55 ppb2014.09 to 23 ppb
2004-05-245.65 ppb504.25 to 7.59 ppb
2004-03-174.11 ppb203.88 to 4.34 ppb
2004-02-237 ppb107 ppb
2004-02-2010.41 ppb503.78 to 20.29 ppb
2004-02-195.11 ppb205 to 5.23 ppb
2004-01-135 ppb304 to 6 ppb
2004-01-086 ppb106 ppb