TTHM & HAA5 Monitoring

Trihalomethanes (TTHM) and Halo acetic Acids (HAA5) are by-products of disinfection. The PA Department of Environmental Protection requires the testing of four samples per quarter to verify maximum contaminant levels of less than 0.080 mg/L for TTHM and 0.060mg/L for HAA5.

However, if the running annual average of TTHM or HAA5 is less than 75% of the maximum contaminant level, DEP can reduce the required monitoring to one sample per quarter. Because of its continued low levels of TTHM and HAA5, ESWA has been on a DEP-sanctioned reduced monitoring schedule of one sample per quarter for TTHM and HAA5 since 2005.