Since the publication of the 1990 Badenoch report into Cryptosporidium in water supplies, UK water companies have been finding ways to improve monitoring and control systems for water treatment processes. Further improvements are still desirable, and the present paper describes work carried out by Anglian Water, in collaboration with University College, London and Diverse Technologies & Systems Ltd of Cambridge, to develop an inexpensive Fine Particle Monitor suitable for routine operational use on water treatment works.