Total Trihalomethanes (TTHM) result when chlorine disinfectants used to treat tap water combine with naturally-occurring organic and inorganic matter present in the water. Known as a disinfection byproduct (DBP), TTHMs are among the substances the Public Utilities Department tests for in our water. TTHMs are present at low levels in most chlorinated water supplies and can also be present in bottled waters.
TTHM production is also a factor of water age…the older the water is, the more TTHMs / DBPs are produced. The GA EPD approves the sample sites with the intent to represent the oldest water (worst-case scenario) in our distribution system.