Upstream Systems with patented Crossfire Technology® are engineered to meet the Class A requirements of NSF/ANSI Standard 55 (but are not NSF/ANSI 55 Class A Certified) where regulations do not require it. Field-tested and proven with over a decade of demanding municipal, industrial and commercial applications. Upstream Systems are for Potable, Reuse and Rainwater applications and are effective even on surface water from lakes, streams, cisterns and dug wells.