Technical control of sewage sludge disposal to sea is carried out primarily to maintain the quality of the receiving environment and this paper discusses the control in the context of England and Wales. Control is exercised in several ways and by several bodies. There are international conventions and national legislation governing sludge dumping, the national legislation is enforced by the Ministry of Agriculture Fisheries and Food, who stipulate the required quality and quantity of sludge. The sludge is produced and disposed of by regional water authorities who must control the quality of their sludge and use trade effluent legislation to control effluent from industry. In turn industrialists must control their effluents to meet water authority standards and this usually requires the installation of water treatment equipment or even change of process. At all stages scientific methods are used to check the effect of the legislative control. It is important that the technical controls used to protect the environment are not over-stringent so that an economic and practicable method of sludge control is not wasted.