Growing emphasis, and rightly so, is being placed on water recovery and reuse to help sustain our planet’s water supplies. By choice or mandate, design engineers for many new industrial plants are selecting alternatives to fresh water for plant makeup, with an increasingly common choice being effluent from a publicly owned treatment works (POTW). These waters go by various names including reclaim water, grey water, purple-pipe water, and so forth. Regardless, virtually all reclaim waters contain elevated concentrations of ammonia, nitrate, organics, phosphate, and suspended solids, all of which, if left untreated, can lead to a nightmare scenario of microbiological fouling in cooling towers and cooling systems; a point that is sometimes not emphasized enough to those designing new facilities or switching supplies at existing plants. But with proper pre-treatment and cooling water chemical treatment, these waters can successfully be utilized for cooling water makeup.