Arsenic
East Walnut Grove [sws]
Arsenic is a potent carcinogen and common contaminant in drinking water. Arsenic causes thousands of cases of cancer each year in the U.S. Click here to read more about arsenic.
Samples
Samples exceeding legal limit (MCL)
Samples exceeding
health guidelines
Testing results - average by year
| Year | Average result | Samples taken | Detections | Range of results |
|---|---|---|---|---|
| 2018 | 7.09 ppb | 37 | 26 | ND - 18.0 ppb |
| 2019 | 8.83 ppb | 39 | 39 | 3.80 ppb - 15.0 ppb |
| 2020 | 9.43 ppb | 37 | 33 | ND - 15.0 ppb |
| 2021 | 7.01 ppb | 37 | 27 | ND - 17.0 ppb |
| 2022 | 7.85 ppb | 33 | 26 | ND - 16.0 ppb |
| 2023 | 7.80 ppb | 25 | 23 | ND - 16.0 ppb |
ppb = parts per billion
State, National, and Health Guidelines for Drinking Water
EWG Health Guideline: 0.004 ppb
The EWG Health Guideline of 0.004 ppb for arsenic was defined by the California Office of Environmental Health Hazard Assessment as a public health goal, the level of a drinking water contaminant that does not pose a significant health risk. This health guideline protects against cancer.
EPA Maximum Contaminant
Level (MCL): 10 ppb
The legal limit for arsenic, established in 2001, was based on costs for arsenic removal, as calculated at the time that the standard was set. This limit does not fully protect against the risk of cancer due to arsenic exposure.
ppb = parts per billion
All test results
| Date | Lab ID | Result |
|---|---|---|
| 2018-01-16 | CA3400106_001_001-201801161116 | 15.0 ppb |
| 2018-01-16 | CA3400106_008_008-201801161118 | 9.10 ppb |
| 2018-01-16 | CA3400106_009_009-201801161120 | 9.90 ppb |
| 2018-02-13 | CA3400106_009_009-201802131048 | ND |
| 2018-02-13 | CA3400106_001_001-201802131045 | 15.0 ppb |
| 2018-02-13 | CA3400106_008_008-201802131047 | ND |
| 2018-03-26 | CA3400106_008_008-201803261120 | ND |
| 2018-03-26 | CA3400106_009_009-201803261121 | ND |
| 2018-03-26 | CA3400106_001_001-201803261122 | 15.0 ppb |
| 2018-04-10 | CA3400106_001_001-201804101301 | 17.0 ppb |
| 2018-04-10 | CA3400106_008_008-201804101304 | ND |
| 2018-04-10 | CA3400106_009_009-201804101306 | ND |
| 2018-05-14 | CA3400106_001_001-201805141118 | 15.0 ppb |
| 2018-05-14 | CA3400106_008_008-201805141122 | ND |
| 2018-05-14 | CA3400106_009_009-201805141123 | ND |
| 2018-06-11 | CA3400106_008_008-201806111250 | ND |
| 2018-06-11 | CA3400106_009_009-201806111252 | ND |
| 2018-06-11 | CA3400106_001_001-201806111248 | 15.0 ppb |
| 2018-07-17 | CA3400106_001_001-201807170945 | 14.0 ppb |
| 2018-07-17 | CA3400106_009_009-201807170947 | ND |
| 2018-07-17 | CA3400106_008_008-201807170946 | 2.10 ppb |
| 2018-08-27 | CA3400106_001_001-201808271012 | 15.0 ppb |
| 2018-08-27 | CA3400106_009_009-201808271018 | 3.20 ppb |
| 2018-08-27 | CA3400106_008_008-201808271017 | 3.50 ppb |
| 2018-09-17 | CA3400106_009_009-201809171010 | 4.10 ppb |
| 2018-09-17 | CA3400106_001_001-201809171007 | 15.0 ppb |
| 2018-09-17 | CA3400106_008_008-201809171009 | 5.50 ppb |
| 2018-10-17 | CA3400106_008_008-201810170923 | 3.50 ppb |
| 2018-10-17 | CA3400106_001_001-201810170922 | 15.0 ppb |
| 2018-10-17 | CA3400106_009_009-201810170924 | 3.20 ppb |
| 2018-11-13 | CA3400106_007_007-201811130957 | 18.0 ppb |
| 2018-11-21 | CA3400106_001_001-201811210848 | 15.0 ppb |
| 2018-11-21 | CA3400106_009_009-201811210850 | 4.60 ppb |
| 2018-11-21 | CA3400106_008_008-201811210849 | 4.20 ppb |
| 2018-12-19 | CA3400106_009_009-201812190847 | 5.20 ppb |
| 2018-12-19 | CA3400106_008_008-201812190846 | 5.40 ppb |
| 2018-12-19 | CA3400106_001_001-201812190845 | 15.0 ppb |
| 2019-01-29 | CA3400106_009_009-201901291017 | 3.80 ppb |
| 2019-01-29 | CA3400106_001_001-201901291015 | 14.0 ppb |
| 2019-01-29 | CA3400106_008_008-201901291018 | 4.30 ppb |
| 2019-02-19 | CA3400106_008_008-201902191414 | 5.40 ppb |
| 2019-02-19 | CA3400106_001_001-201902191413 | 15.0 ppb |
| 2019-02-19 | CA3400106_009_009-201902191415 | 5.30 ppb |
| 2019-03-19 | CA3400106_001_001-201903191025 | 15.0 ppb |
| 2019-03-19 | CA3400106_008_008-201903191028 | 5.40 ppb |
| 2019-03-19 | CA3400106_009_009-201903191029 | 5.40 ppb |
| 2019-04-18 | CA3400106_001_001-201904180911 | 14.0 ppb |
| 2019-04-18 | CA3400106_008_008-201904180913 | 5.60 ppb |
| 2019-04-18 | CA3400106_009_009-201904180916 | 5.40 ppb |
| 2019-05-21 | CA3400106_001_001-201905211044 | 14.0 ppb |
| 2019-05-21 | CA3400106_008_008-201905211048 | 4.80 ppb |
| 2019-05-21 | CA3400106_009_009-201905211050 | 4.70 ppb |
| 2019-06-17 | CA3400106_001_001-201906170902 | 15.0 ppb |
| 2019-06-17 | CA3400106_009_009-201906170906 | 5.90 ppb |
| 2019-06-17 | CA3400106_008_008-201906170905 | 5.60 ppb |
| 2019-07-09 | CA3400106_009_009-201907091029 | 6.00 ppb |
| 2019-07-09 | CA3400106_001_001-201907091022 | 14.0 ppb |
| 2019-07-09 | CA3400106_008_008-201907091026 | 6.00 ppb |
| 2019-08-22 | CA3400106_001_001-201908221038 | 14.0 ppb |
| 2019-08-22 | CA3400106_009_009-201908221041 | 7.60 ppb |
| 2019-08-22 | CA3400106_008_008-201908221040 | 8.50 ppb |
| 2019-09-09 | CA3400106_001_001-201909091213 | 14.0 ppb |
| 2019-09-09 | CA3400106_009_009-201909091217 | 6.40 ppb |
| 2019-09-09 | CA3400106_008_008-201909091215 | 6.60 ppb |
| 2019-10-23 | CA3400106_001_001-201910231025 | 14.0 ppb |
| 2019-10-23 | CA3400106_008_008-201910231027 | 7.90 ppb |
| 2019-10-23 | CA3400106_009_009-201910231030 | 7.30 ppb |
| 2019-11-04 | CA3400106_008_008-201911041056 | 7.00 ppb |
| 2019-11-04 | CA3400106_009_009-201911041058 | 7.40 ppb |
| 2019-11-04 | CA3400106_001_001-201911041054 | 14.0 ppb |
| 2019-11-21 | CA3400106_008_008-201911210926 | 6.40 ppb |
| 2019-11-21 | CA3400106_009_009-201911210929 | 7.00 ppb |
| 2019-11-21 | CA3400106_001_001-201911210925 | 13.0 ppb |
| 2019-12-19 | CA3400106_009_009-201912190831 | 7.20 ppb |
| 2019-12-19 | CA3400106_001_001-201912190825 | 14.0 ppb |
| 2019-12-19 | CA3400106_008_008-201912190827 | 7.50 ppb |
| 2020-01-07 | CA3400106_001_001-202001071102 | 15.0 ppb |
| 2020-01-07 | CA3400106_008_008-202001071113 | 7.90 ppb |
| 2020-01-07 | CA3400106_009_009-202001071114 | 7.90 ppb |
| 2020-02-11 | CA3400106_001_001-202002110827 | 14.0 ppb |
| 2020-02-20 | CA3400106_008_008-202002201048 | 8.30 ppb |
| 2020-02-20 | CA3400106_009_009-202002201048 | 8.00 ppb |
| 2020-02-20 | CA3400106_001_001-202002201048 | 14.0 ppb |
| 2020-03-25 | CA3400106_001_001-202003250641 | 15.0 ppb |
| 2020-03-25 | CA3400106_008_008-202003250642 | 7.50 ppb |
| 2020-03-25 | CA3400106_009_009-202003250642 | 7.90 ppb |
| 2020-04-20 | CA3400106_001_001-202004201009 | 14.0 ppb |
| 2020-04-20 | CA3400106_008_008-202004201012 | 8.80 ppb |
| 2020-04-20 | CA3400106_009_009-202004201014 | 9.20 ppb |
| 2020-05-18 | CA3400106_008_008-202005181045 | 7.20 ppb |
| 2020-05-18 | CA3400106_001_001-202005181050 | 14.0 ppb |
| 2020-05-18 | CA3400106_009_009-202005181046 | 7.10 ppb |
| 2020-06-29 | CA3400106_009_009-202006290931 | 9.60 ppb |
| 2020-06-29 | CA3400106_001_001-202006290929 | 15.0 ppb |
| 2020-06-29 | CA3400106_008_008-202006290930 | 8.80 ppb |
| 2020-07-20 | CA3400106_001_001-202007201136 | 13.0 ppb |
| 2020-07-20 | CA3400106_008_008-202007201137 | 7.00 ppb |
| 2020-07-20 | CA3400106_009_009-202007201139 | 7.40 ppb |
| 2020-08-25 | CA3400106_001_001-202008251115 | 15.0 ppb |
| 2020-08-25 | CA3400106_008_008-202008251115 | 9.50 ppb |
| 2020-08-25 | CA3400106_009_009-202008251115 | 11.0 ppb |
| 2020-09-17 | CA3400106_008_008-202009171252 | 6.90 ppb |
| 2020-09-17 | CA3400106_009_009-202009171254 | 6.80 ppb |
| 2020-09-17 | CA3400106_001_001-202009171254 | 14.0 ppb |
| 2020-10-05 | CA3400106_001_001-202010051426 | 15.0 ppb |
| 2020-10-05 | CA3400106_008_008-202010051426 | 7.80 ppb |
| 2020-10-05 | CA3400106_009_009-202010051427 | 7.30 ppb |
| 2020-11-24 | CA3400106_008_008-202011241013 | ND |
| 2020-11-24 | CA3400106_001_001-202011241010 | 14.0 ppb |
| 2020-11-24 | CA3400106_009_009-202011241014 | ND |
| 2020-12-22 | CA3400106_001_001-202012220844 | 15.0 ppb |
| 2020-12-22 | CA3400106_008_008-202012220845 | ND |
| 2020-12-22 | CA3400106_009_009-202012220845 | ND |
| 2021-01-07 | CA3400106_009_009-202101071231 | ND |
| 2021-01-07 | CA3400106_001_001-202101071229 | 15.0 ppb |
| 2021-01-07 | CA3400106_008_008-202101071230 | ND |
| 2021-02-22 | CA3400106_001_001-202102221123 | 15.0 ppb |
| 2021-02-22 | CA3400106_009_009-202102221125 | ND |
| 2021-02-22 | CA3400106_008_008-202102221124 | ND |
| 2021-03-15 | CA3400106_001_001-202103151350 | 15.0 ppb |
| 2021-03-15 | CA3400106_008_008-202103151353 | ND |
| 2021-03-15 | CA3400106_009_009-202103151353 | ND |
| 2021-04-21 | CA3400106_001_001-202104211015 | 14.0 ppb |
| 2021-04-21 | CA3400106_008_008-202104211016 | ND |
| 2021-04-21 | CA3400106_009_009-202104211017 | ND |
| 2021-05-17 | CA3400106_009_009-202105171403 | ND |
| 2021-05-17 | CA3400106_001_001-202105171401 | 15.0 ppb |
| 2021-05-17 | CA3400106_008_008-202105171402 | ND |
| 2021-06-21 | CA3400106_009_009-202106211220 | 4.00 ppb |
| 2021-06-21 | CA3400106_001_001-202106211218 | 15.0 ppb |
| 2021-06-21 | CA3400106_008_008-202106211220 | 2.50 ppb |
| 2021-07-14 | CA3400106_001_001-202107141026 | 14.0 ppb |
| 2021-07-14 | CA3400106_009_009-202107141028 | 3.30 ppb |
| 2021-07-14 | CA3400106_008_008-202107141027 | 2.10 ppb |
| 2021-08-30 | CA3400106_008_008-202108301225 | 4.10 ppb |
| 2021-08-30 | CA3400106_001_001-202108301224 | 14.0 ppb |
| 2021-08-30 | CA3400106_009_009-202108301225 | 5.10 ppb |
| 2021-09-23 | CA3400106_008_008-202109231323 | 3.10 ppb |
| 2021-09-23 | CA3400106_009_009-202109231324 | 4.30 ppb |
| 2021-09-23 | CA3400106_001_001-202109231322 | 15.0 ppb |
| 2021-10-19 | CA3400106_009_009-202110191208 | 5.30 ppb |
| 2021-10-19 | CA3400106_008_008-202110191207 | 4.90 ppb |
| 2021-10-19 | CA3400106_001_001-202110191206 | 15.0 ppb |
| 2021-11-08 | CA3400106_007_007-202111080913 | 17.0 ppb |
| 2021-11-15 | CA3400106_001_001-202111150914 | 16.0 ppb |
| 2021-11-15 | CA3400106_008_008-202111150915 | 5.60 ppb |
| 2021-11-15 | CA3400106_009_009-202111150916 | 6.40 ppb |
| 2021-12-16 | CA3400106_001_001-202112161045 | 15.0 ppb |
| 2021-12-16 | CA3400106_008_008-202112161048 | 6.20 ppb |
| 2021-12-16 | CA3400106_009_009-202112161048 | 7.30 ppb |
| 2022-01-10 | CA3400106_009_009-202201101120 | 7.50 ppb |
| 2022-01-10 | CA3400106_001_001-202201101118 | 16.0 ppb |
| 2022-01-10 | CA3400106_008_008-202201101120 | 6.20 ppb |
| 2022-02-24 | CA3400106_008_008-202202240836 | 7.10 ppb |
| 2022-02-24 | CA3400106_001_001-202202240835 | 15.0 ppb |
| 2022-02-24 | CA3400106_009_009-202202240836 | 6.00 ppb |
| 2022-03-21 | CA3400106_009_009-202203211310 | 6.30 ppb |
| 2022-03-21 | CA3400106_008_008-202203211310 | 5.50 ppb |
| 2022-03-21 | CA3400106_001_001-202203211300 | 14.0 ppb |
| 2022-04-20 | CA3400106_001_001-202204201054 | 16.0 ppb |
| 2022-04-20 | CA3400106_008_008-202204201142 | 8.60 ppb |
| 2022-04-20 | CA3400106_009_009-202204201142 | 10.00 ppb |
| 2022-05-18 | CA3400106_001_001-202205180915 | 15.0 ppb |
| 2022-05-18 | CA3400106_008_008-202205180915 | 6.60 ppb |
| 2022-05-18 | CA3400106_009_009-202205180915 | 7.50 ppb |
| 2022-06-07 | CA3400106_001_001-202206070837 | 14.0 ppb |
| 2022-06-07 | CA3400106_008_008-202206070840 | 7.30 ppb |
| 2022-06-07 | CA3400106_009_009-202206070842 | 7.80 ppb |
| 2022-08-09 | CA3400106_008_008-202208091211 | ND |
| 2022-08-09 | CA3400106_009_009-202208091211 | ND |
| 2022-08-09 | CA3400106_001_001-202208091210 | 14.0 ppb |
| 2022-09-13 | CA3400106_009_009-202209131045 | ND |
| 2022-09-13 | CA3400106_008_008-202209131045 | ND |
| 2022-09-13 | CA3400106_001_001-202209131040 | 15.0 ppb |
| 2022-10-24 | CA3400106_001_001-202210241019 | 15.0 ppb |
| 2022-10-24 | CA3400106_008_008-202210241020 | ND |
| 2022-10-24 | CA3400106_009_009-202210241020 | ND |
| 2022-11-17 | CA3400106_008_008-202211171100 | ND |
| 2022-11-17 | CA3400106_001_001-202211171059 | 16.0 ppb |
| 2022-11-17 | CA3400106_009_009-202211171101 | 2.90 ppb |
| 2022-12-19 | CA3400106_001_001-202212190800 | 14.0 ppb |
| 2022-12-19 | CA3400106_008_008-202212190814 | 2.70 ppb |
| 2022-12-19 | CA3400106_009_009-202212190815 | 3.20 ppb |
| 2023-01-11 | CA3400106_001_001-202301111210 | 13.0 ppb |
| 2023-01-11 | CA3400106_008_008-202301111212 | ND |
| 2023-01-11 | CA3400106_009_009-202301111212 | ND |
| 2023-02-14 | CA3400106_001_001-202302140834 | 13.0 ppb |
| 2023-02-27 | CA3400106_001_001-202302270945 | 14.0 ppb |
| 2023-02-27 | CA3400106_009_009-202302270947 | 3.90 ppb |
| 2023-02-27 | CA3400106_008_008-202302270946 | 3.40 ppb |
| 2023-03-28 | CA3400106_009_009-202303281140 | 4.30 ppb |
| 2023-03-28 | CA3400106_001_001-202303281135 | 16.0 ppb |
| 2023-03-28 | CA3400106_008_008-202303281140 | 4.30 ppb |
| 2023-04-20 | CA3400106_009_009-202304200834 | 5.10 ppb |
| 2023-04-20 | CA3400106_001_001-202304200832 | 14.0 ppb |
| 2023-04-20 | CA3400106_008_008-202304200834 | 4.10 ppb |
| 2023-05-09 | CA3400106_001_001-202305090817 | 15.0 ppb |
| 2023-05-09 | CA3400106_008_008-202305090825 | 4.00 ppb |
| 2023-05-09 | CA3400106_009_009-202305090826 | 5.10 ppb |
| 2023-06-22 | CA3400106_001_001-202306221003 | 13.0 ppb |
| 2023-06-22 | CA3400106_009_009-202306221005 | 5.80 ppb |
| 2023-06-22 | CA3400106_008_008-202306221005 | 5.10 ppb |
| 2023-07-12 | CA3400106_009_009-202307121145 | 5.30 ppb |
| 2023-07-12 | CA3400106_001_001-202307121143 | 13.0 ppb |
| 2023-07-12 | CA3400106_008_008-202307121144 | 4.70 ppb |
| 2023-08-21 | CA3400106_008_008-202308210900 | 7.10 ppb |
| 2023-08-21 | CA3400106_001_001-202308210900 | 15.0 ppb |
| 2023-08-21 | CA3400106_009_009-202308210900 | 6.80 ppb |