Disinfection byproducts are compounds that form when chlorine-a disinfectant, mixes with naturally occurring organic material in the water. Disinfectants are added to water to eliminate water-borne diseases like cholera, dysentery, and typhoid. The disinfection byproducts that occur most frequently are trihalomethanes (THMs,) and haloacetic acids (HAAs.)
Since 1995, when MMWD changed the distribution system disinfectant from chlorine to chloramine, a combination of chlorine and ammonia, MMWD has achieved a 57% reduction in THMs on average. The federal standard for THMs is 80 micrograms per liter (ug/L,) or parts per billion, while the THM count in MMWD's water averages 31 ug/L.
While HAA monitoring was not required before the conversion to chloramine, it has been well documented that the use of chloramine for a residual disinfectant significantly reduces the formation of HAAs. The average concentration found in MMWD’s distribution system is approximately one-third of the federal standard of 60 ug/L.