Manteca has been effectively removing TCP from municipal well water over the past decade. Described by the state as a “potent carcinogen”, it has been detected in a handful of city wells over the years as the plume of contamination spreads hundreds of feet below ground. Most of the city’s wells aren’t impacted. The effective removal of the containment TCP — 1,2,3-trichloropapne — from municipal water has been a priority for the city since it was first detected in a well in 2013. … Extremely small traces of the chemical TCP used in pesticides for orchard crops as well as in industrial solvents has been detected in several Manteca municipal water wells over the years.