Nitrification in drinking water distribution systems is a concern of many drinking water systems. Although chloramination as a source of nitrification has drawn the most attention, many source waters contain significant levels of ammonia, particularly in Midwestern States such as Illinois.
Aside from taste and odor complaints often accompanying nitrification, more potentially concerning is the formation of nitrite and nitrate in the distribution system, both of which have MCLs of 1 mg/L NO2-N and 10 mg/L NO3-N, respectively.