Nitrification and potential control mechanisms in simulated premises plumbing

► Nitrification occurred in simulated PVC and copper premises plumbing systems. ► Copper surfaces or added ionic copper did not control nitrification. ► Chlorite controlled nitrification on copper but only at an unreasonably high dose of 20 ppm. ► High chlorine to ammonia ratios (5:1) controlled nitrification on PVC but was less effective on copper.