EWG's Tap Water Database — 2019 UPDATE


Haloacetic acids (HAA5)

Avon Water Company

Haloacetic acids are formed when disinfectants such as chlorine are added to tap water. The group of five haloacetic acids regulated by federal standards includes monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, monobromoacetic acid and dibromoacetic acid. Read More.

Haloacetic acids are harmful during pregnancy and may increase the risk of cancer. Haloacetic acids are genotoxic, which means that they induce mutations and DNA damage. Multiple studies by the National Toxicology Program have demonstrated the cancer-causing properties of individual haloacetic acids in laboratory animals. The Department of Health and Human Services is currently considering listing di- or tri-haloacetic acids for possible inclusion in its comprehensive Report on Carcinogens.

Click here to read more about disinfection byproducts.





Samples exceeding legal limit (MCL)


Samples exceeding
health guidelines

Testing results - average by year

YearAverage resultSamples takenDetectionsRange of results
20120.631 ppb2013ND - 1.60 ppb
20131.04 ppb1917ND - 2.70 ppb
20141.21 ppb16160.560 ppb - 3.50 ppb
20151.19 ppb1614ND - 3.40 ppb
20162.03 ppb16160.530 ppb - 4.80 ppb
20172.28 ppb16160.700 ppb - 5.40 ppb

ppb = parts per billion

State and national drinking water standards and health guidelines

EWG Health Guideline 0.1 ppb

The EWG Health Guideline of 0.1 ppb for the group of five haloacetic acids, or HAA5, was defined in a peer-reviewed scientific study by EWG and represents a on-in-a-million lifetime cancer risk level. This health guideline protects against cancer.

EPA Maximum Contaminant
Level (MCL) 60 ppb

The legal limit for the group of five haloacetic acids (HAA5), established in 1998, was based on the need for residual disinfectant levels in water served to customers and the cost of treatment. This limit does not fully protect against the risk of cancer and harm to the developing fetus due to exposure to haloacetic acids.

ppb = parts per billion

All test results

Date Lab ID Result
2012-02-13E202660-4-4CH0.650 ppb
2012-02-13E202660-5-5CH0.550 ppb
2012-05-18E205C39-1-1CH1.20 ppb
2012-05-18E205C39-2-2CH1.10 ppb
2012-05-18E205C39-4-4CH0.830 ppb
2012-05-18E205C39-5-5CH1.60 ppb
2012-08-27E208I95-1-1CH1.30 ppb
2012-08-27E208I95-2-2CH0.750 ppb
2012-08-27E208I95-3-3CH0.890 ppb
2012-11-26E211J93-1-1CH1.36 ppb
2012-11-26E211J93-2-2CH0.520 ppb
2012-11-26E211J93-3-3CH0.620 ppb
2012-11-26E211J93-4-4CH1.24 ppb
2013-02-14E302947-1-1CH0.820 ppb
2013-02-14E302947-2-2CH0.800 ppb
2013-02-14E302947-3-3CH0.710 ppb
2013-02-14E302947-4-4CH0.780 ppb
2013-02-14E302947-5-5CH1.80 ppb
2013-05-21E305J33-1-1CH1.30 ppb
2013-05-21E305J33-2-2CH1.30 ppb
2013-05-21E305J33-4-4CH0.650 ppb
2013-05-21E305J33-5-5CH2.60 ppb
2013-08-23E308O40-10-2CH0.940 ppb
2013-08-23E308O40-11-3CH1.10 ppb
2013-08-23E308O40-12-4CH0.810 ppb
2013-08-23E308O40-9-1CH2.70 ppb
2013-11-15E311D00-10-2CH0.690 ppb
2013-11-15E311D00-11-3CH0.760 ppb
2013-11-15E311D00-12-5CH1.10 ppb
2013-11-15E311D00-9-1CH0.950 ppb
2014-01-16E401A25-1CH1.000 ppb
2014-01-16E401A25-2CH1.27 ppb
2014-01-16E401A25-3CH1.18 ppb
2014-01-16E401A25-4CH1.40 ppb
2014-04-15E404E43-1CH1.20 ppb
2014-04-15E404E43-2CH1.10 ppb
2014-04-15E404E43-3CH1.30 ppb
2014-04-15E404E43-4CH0.600 ppb
2014-07-14E407C09-1GE1.10 ppb
2014-07-14E407C09-2GE1.20 ppb
2014-07-14E407C09-3GE3.50 ppb
2014-07-14E407C09-4GE0.650 ppb
2014-10-16E410F41-1GE0.640 ppb
2014-10-16E410F41-2GE1.34 ppb
2014-10-16E410F41-3GE0.560 ppb
2014-10-16E410F41-4GE1.30 ppb
2015-01-15E501A25-1GE0.580 ppb
2015-01-15E501A25-2GE0.840 ppb
2015-01-15E501A25-4GE0.520 ppb
2015-01-15E501A25-3GE0.930 ppb
2015-04-14E504E21-1GE0.900 ppb
2015-04-14E504E21-2GE0.690 ppb
2015-04-14E504E21-3GE1.000 ppb
2015-07-15E507G94-2GE1.80 ppb
2015-07-15E507G94-4GE0.710 ppb
2015-07-15E507G94-1GE1.50 ppb
2015-07-15E507G94-3GE3.40 ppb
2015-10-15E510E91-2GE2.80 ppb
2015-10-15E510E91-1GE1.80 ppb
2015-10-15E510E91-3GE1.50 ppb
2016-01-15E601D17-1GE2.60 ppb
2016-01-15E601D17-2GE2.20 ppb
2016-01-15E601D17-3GE2.40 ppb
2016-01-15E601D17-4GE0.730 ppb
2016-04-19E605079-1GE1.60 ppb
2016-04-19E605079-2GE1.40 ppb
2016-04-19E605079-3GE2.10 ppb
2016-04-19E605079-4GE1.000 ppb
2016-07-13E607C00-1GE4.80 ppb
2016-07-13E607C00-2GE2.20 ppb
2016-07-13E607C00-3GE4.50 ppb
2016-07-13E607C00-4GE0.530 ppb
2016-10-14E610G73-1GE1.40 ppb
2016-10-14E610G73-2GE1.90 ppb
2016-10-14E610G73-3GE2.20 ppb
2016-10-14E610G73-4GE0.980 ppb
2017-01-13E701C67-1GE2.80 ppb
2017-01-13E701C67-2GE1.30 ppb
2017-01-13E701C67-3GE1.40 ppb
2017-01-13E701C67-4GE1.000 ppb
2017-04-13D7D1107-01HA51.60 ppb
2017-04-13D7D1107-02HA52.70 ppb
2017-04-13D7D1107-03HA51.80 ppb
2017-04-13D7D1107-04HA52.20 ppb
2017-07-14D7G1331-01HA53.10 ppb
2017-07-14D7G1331-02HA55.40 ppb
2017-07-14D7G1331-03HA53.60 ppb
2017-07-14D7G1331-04HA50.800 ppb
2017-10-13D7J1362-01HA53.30 ppb
2017-10-13D7J1362-02HA52.70 ppb
2017-10-13D7J1362-03HA52.10 ppb
2017-10-13D7J1362-04HA50.700 ppb