Tetrachloroethylene (perchloroethylene)
Hillview Water Company-oakhurst/sierra Lakes
Dry cleaning chemical tetrachloroethylene, or perc, can cause cancer. It pollutes soil and groundwater due to emissions from dry cleaning facilities, and automotive, metalworking and other industries. Read More.
The EPA considers tetrachloroethylene a likely human carcinogen. It has been linked with increased incidence of lung, breast and colon cancers. Tetrachloroethylene also damages the liver, kidneys and central nervous system. The California public health goal of 0.06 parts per billion, set to protect against cancer, is 80 times lower than the amount allowed by the federal government, which is a Maximum Contaminant Level of 5 parts per billion.
Samples
Samples exceeding legal limit (MCL)
Samples exceeding
health guidelines
Testing results - average by year
| Year | Average result | Samples taken | Detections | Range of results |
|---|---|---|---|---|
| 2014 | 1.13 ppb | 12 | 6 | ND - 4.80 ppb |
| 2015 | 2.54 ppb | 13 | 12 | ND - 7.70 ppb |
| 2016 | 0.712 ppb | 22 | 6 | ND - 7.50 ppb |
| 2017 | 1.36 ppb | 11 | 7 | ND - 7.80 ppb |
| 2018 | 0.622 ppb | 23 | 4 | ND - 8.20 ppb |
| 2019 | 0.144 ppb | 15 | 2 | ND - 1.20 ppb |
ppb = parts per billion
State and national drinking water standards and health guidelines
EWG Health Guideline 0.06 ppb
The EWG Health Guideline of 0.06 ppb for tetrachloroethylene 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) 5 ppb
The legal limit for tetrachloroethylene, established in 1991, was based on analytical detection limits at the time that the standard was set. This limit does not fully protect against the risk of cancer due to tetrachloroethylene exposure.
ppb = parts per billion
All test results
| Date | Lab ID | Result |
|---|---|---|
| 2014-01-22 | 5810-017-1120 | ND |
| 2014-01-22 | 5810-028-1520 | ND |
| 2014-04-17 | 5810-017-1442 | 0.610 ppb |
| 2014-04-17 | 5810-028-1432 | ND |
| 2014-07-23 | 5810-017-0940 | 2.50 ppb |
| 2014-07-23 | 5810-028-1000 | ND |
| 2014-10-16 | 5810-017-1325 | 4.80 ppb |
| 2014-10-21 | 5810-028-1515 | ND |
| 2014-11-05 | 5810-028-1125 | ND |
| 2014-11-10 | 5810-017-0800 | 2.80 ppb |
| 2014-12-01 | 5810-028-0750 | 1.40 ppb |
| 2014-12-01 | 5810-017-0805 | 1.40 ppb |
| 2015-01-05 | 5810-028-0743 | 1.60 ppb |
| 2015-01-05 | 5810-017-0753 | 2.10 ppb |
| 2015-02-09 | 5810-017-1117 | 3.80 ppb |
| 2015-02-09 | 5810-028-1125 | ND |
| 2015-04-20 | 5810-017-1134 | 5.60 ppb |
| 2015-04-20 | 5810-028-1143 | 0.790 ppb |
| 2015-05-19 | 5810-028-1010 | 2.20 ppb |
| 2015-05-19 | 5810-017-0850 | 1.10 ppb |
| 2015-06-08 | 5810-017-1504 | 0.880 ppb |
| 2015-07-14 | 5810-028-0958 | 1.40 ppb |
| 2015-07-14 | 5810-017-0935 | 4.90 ppb |
| 2015-10-06 | 5810-028-1030 | 1.000 ppb |
| 2015-10-06 | 5810-017-1013 | 7.70 ppb |
| 2016-01-19 | 5810-017-1114 | 7.50 ppb |
| 2016-01-19 | 5810-028-1125 | ND |
| 2016-04-18 | 5810-017-1040 | 0.670 ppb |
| 2016-04-18 | 5810-028-1055 | ND |
| 2016-07-19 | 5810-028-1056 | 2.00 ppb |
| 2016-07-19 | 5810-017-1500 | 1.90 ppb |
| 2016-09-19 | 5810-003-1549 | ND |
| 2016-09-19 | 5810-001-1535 | ND |
| 2016-09-19 | 5810-032-1610 | ND |
| 2016-10-18 | 5810-017-1434 | 0.600 ppb |
| 2016-10-18 | 5810-028-1450 | 3.00 ppb |
| 2016-11-08 | 5810-007-1337 | ND |
| 2016-11-08 | 5810-002-1025 | ND |
| 2016-11-16 | 5810-009-0936 | ND |
| 2016-12-20 | 5810-034-1128 | ND |
| 2016-12-20 | 5810-031-1050 | ND |
| 2016-12-20 | 5810-039-1325 | ND |
| 2016-12-20 | 5810-030-1038 | ND |
| 2016-12-20 | 5810-040-1342 | ND |
| 2016-12-20 | 5810-041-1420 | ND |
| 2016-12-20 | 5810-033-1102 | ND |
| 2016-12-20 | 5810-010-0939 | ND |
| 2017-01-16 | 5810-028-1540 | 1.10 ppb |
| 2017-01-16 | 5810-017-1550 | 0.540 ppb |
| 2017-04-11 | 5810-028-1422 | 1.30 ppb |
| 2017-04-11 | 5810-017-1409 | 1.70 ppb |
| 2017-07-11 | 5810-017-1535 | 1.60 ppb |
| 2017-07-12 | 5810-028-1058 | 0.870 ppb |
| 2017-08-15 | 5810-040-1608 | ND |
| 2017-08-15 | 5810-039-1555 | ND |
| 2017-08-15 | 5810-041-1626 | ND |
| 2017-10-17 | 5810-028-1340 | ND |
| 2017-10-17 | 5810-017-1329 | 7.80 ppb |
| 2018-01-02 | 5810-028-1622 | ND |
| 2018-01-02 | 5810-017-1611 | 8.20 ppb |
| 2018-04-03 | 5810-017-1510 | 2.30 ppb |
| 2018-04-03 | 5810-028-1523 | ND |
| 2018-04-30 | 5810-048-1432 | ND |
| 2018-04-30 | 5810-047-1410 | ND |
| 2018-04-30 | 5810-046-1410 | ND |
| 2018-05-23 | 5810-024-1020 | ND |
| 2018-05-25 | 5810-046-0932 | ND |
| 2018-05-25 | 5810-046-1000 | ND |
| 2018-07-10 | 5810-048-1418 | ND |
| 2018-07-10 | 5810-017-1600 | 2.30 ppb |
| 2018-07-10 | 5810-047-1445 | ND |
| 2018-07-10 | 5810-024-1515 | ND |
| 2018-07-10 | 5810-046-1325 | ND |
| 2018-07-25 | 5810-009-1000 | ND |
| 2018-07-31 | 5810-028-1023 | ND |
| 2018-08-22 | 5810-010-1022 | ND |
| 2018-10-09 | 5810-028-1323 | ND |
| 2018-10-09 | 5810-017-1310 | 1.50 ppb |
| 2018-10-10 | 5810-046-0925 | ND |
| 2018-10-10 | 5810-047-1002 | ND |
| 2018-10-10 | 5810-048-1041 | ND |
| 2019-01-08 | 5810-046-1140 | ND |
| 2019-01-08 | 5810-047-1315 | ND |
| 2019-01-10 | 5810-028-0950 | ND |
| 2019-01-10 | 5810-017-0935 | 1.20 ppb |
| 2019-02-13 | 5810-048-0910 | ND |
| 2019-04-10 | 5810-017-1009 | 0.960 ppb |
| 2019-09-12 | 5810-032-0832 | ND |
| 2019-10-29 | 5810-032-0925 | ND |
| 2019-10-29 | 5810-003-0903 | ND |
| 2019-10-29 | 5810-001-0852 | ND |
| 2019-12-23 | 5810-034-0831 | ND |
| 2019-12-23 | 5810-033-0916 | ND |
| 2019-12-30 | 5810-030-0837 | ND |
| 2019-12-30 | 5810-031-0844 | ND |
| 2019-12-30 | 5810-007-0849 | ND |