Instrumentation, control and automation (ICA) of wastewater treatment systems and sewer networks have attracted much attention since the early 1970s. The developments during the last four decades in on-line instrumentation, computer technology, process understanding and subsequent model development, and control methods have been powerful driving forces for advanced control making ICA ever more profitable. Today computational power is almost “for free”. The instrumentation development shows a progress towards “smarter” sensors with multiple heads, possible to be placed anywhere in the processes. Actuators such as variable speed drives for pumps and compressors make control more flexible. Control engineering today can offer “almost any method” that the water operator would need.