This paper aims to demonstrate that the regulation of drinking water quality in England and Wales has been successful in securing the improvements to drinking water quality resulting in better performance against EU and national standards. The water industry in England and Wales went through a major change in 1989 when suppliers were privatised and the government set up a robust regulatory regime. The regime was necessary as the industry was, as a result of privatisation, a monopoly with customers having no choice of supplier, unlike what was later available with other utilities such as gas or electricity. The regime would protect the interests of the consumer, the environment and public health through the quality of the product. The Drinking Water Inspectorate (DWI), as established in 1990, had to ensure the implementation of the European Drinking Water Directive (DWD) that had been transposed into national legislation. The aim of the DWD is to ensure that all EU Member States provide drinking water of a prescribed quality. In England and Wales, a body was required to oversee the performance of the industry against those standards, reporting to the Government and the European Commission. Through acts and legislation, the set up of the industry, the duties of the suppliers and regulators and the powers available to the regulators were established. The improvements to drinking water quality since privatisation were achieved by massive investment of the privatised water industry overseen by an independent regulator with clear duties and the powers to inspect, enforce and prosecute. The DWI's achievements show that to improve quality performance with the ability to report in detail how the improvements were made with extensive data evidence, a special regulator is required. The DWI advises policy departments and Ministers and when there are serious concerns regarding a threat to human health through drinking water, the highest level of regulatory power is the creation of new legislation, for example, the Cryptosporidium regulations that are unique to the UK. The DWI is more than what is traditionally thought of as a regulator because it has a single remit--drinking water quality--and its style of regulation has been key to improved drinking water quality in England and Wales.