This paper presents a feasibility study of employing electrical resistance tomography (ERT) technology for monitoring water based cleaning-in-place (CIP) processes. Specially designed 1.5 '' transparent Perspex pipes of different geometries, fitted with multiple planes of inline ERT probes, were filled with a non-Newtonian shampoo product, and then cleaned by flushing fresh tap water through at different flow rates ranging from 4000 to 8000 kg/h. The maximum pixel conductivity, defined as the maximum of the reconstructed 316 pixel conductivities in each ERT frame, was proved to be a sound and robust cleaning process monitoring indicator. The investigation demonstrated that the ERT technology is capable of shedding more detailed insights into the CIP process than any other monitoring technologies currently being employed. (C) 2016 The Authors. Published by Elsevier B.V. on behalf of Institution of Chemical Engineers.