Capítulo 2: Marco Referencial
2.5.2. Conferencias, discursos y congresos
Gary Lau
11.1
Introduction
This chapter outlines the arrangements for public water supply in England and Wales, and the role of the DWI in enforcing regulatory requirements. The management of incidents affecting drinking water quality is described using examples to highlight some of the issues associated with minimizing harm to the population. Analytical support, health risks and toxicological advice, inter-agency assistance, and communication are considered.
The need for effective and rapid communications between all relevant bodies in the event of a chemical contamination incident affecting public water supplies and the ready availability of an assessment of potential health risks and provision of toxicological advice are highlighted.
11.2
The Drinking Water Inspectorate
11.2.1 Background
The DWI was formed on 2 January 1990 following the privatization of the water industry.
It provides independent reassurance that public water supplies in England and Wales are safe and acceptable to consumers.
Learning outcomes
At the end of this chapter and any recommended reading the student should be able to:
1. explain the processes and guidelines for the provision of safe public water supply in England and Wales;
2. evaluate the roles of the Drinking Water Inspectorate (DWI), local authorities, and the water utilities;
3. explain the importance of good analytical support and toxicological advice, plus inter-agency assistance and effective communications in the event of the chemical contamination of public water supplies;
4. critically discuss examples of chemical water contamination incidents and evaluate the manner in which investigations were carried out, and
5. apply acquired knowledge in the analysis and management of hazardous situations.
11.2.2 Public water supplies
A public water supply is one which is provided for the purposes of drinking, washing, cooking and food production by a statutorily appointed water company. From December 2005, non-domestic consumers who use at least 50 m 3 of water a year were able to purchase water from either their existing company or from a licensed water supplier.
11.2.3 Private water supplies
Water that is not supplied by a statutorily appointed water company is called private water. Local authorities are responsible under the Water Industry Act 1991 for checking the safety and sufficiency of water supplies in their area, including private water supplies.
The DWI provides expert technical advice to local authorities but has no regulatory role.
Private water supplies make up less than 2 % of the total water supply in England and Wales, and most such supplies are in rural and remote parts of the country.
11.2.4 Regulatory framework
The Water Industry Act 1991 sets out the regulatory framework and defines the powers and duties under which the DWI operates as well as the responsibilities of water compa-nies. Under the Act, the Secretary of State for Environment, Food and Rural Affairs and the National Assembly for Wales are responsible for regulating the quality of public water supplies. These two authorities appoint the Chief Inspector of Drinking Water to act on their behalf to enforce water quality standards and, where appropriate, initiate prosecu-tions. The Water Act 2003 (Section 57) provides for the appointment of the Chief Inspector of Drinking Water and amends the Water Industry Act to allow for the appoint-ment of inspectors.
11.2.5 Wholesome water
By law (Section 68 of the Water Industry Act 1991 ) water companies must supply water that is wholesome at the time of supply. Wholesomeness is defined by reference to drinking water standards and other requirements set out in the Water Supply (Water Quality) Regulations 2000 (2010 in Wales) (the Regulations). Many of these regulations derive from the 1998 European Drinking Water Directive (Council Directive 1998 ), which came fully into force on 25 December 2003. Until December 2003, the standards contained within the Water Supply (Water Quality) Regulations 1989 applied.
The standards are directly linked to the World Health Organization (WHO) guideline values for drinking water quality, which are intended to protect public health as well as ensuring that water supplies are aesthetically acceptable to consumers. Under the EC Directive, standards will be subject to revision in the light of new knowledge. The new Regulations contain some new and revised standards; others that are no longer appropriate have been withdrawn. Although the Directive focuses on those parameters of importance to human health, others are included which relate to the control of water treatment processes and the aesthetic quality of drinking water. The Directive allows member states to set additional or tighter national standards to preserve the already good quality of drinking water and to prevent future deterioration.
11.2.6 Testing and reporting
Water companies are required to collect and test samples of the water leaving water treatment and service reservoirs and from randomly selected consumers’ properties. The tests to be carried out and the frequency of testing are detailed in the Regulations and the Water Supply Regulations (2010). The DWI checks independently that the testing is carried out to the highest standards and that appropriate quality control checks are in place to assure the integrity of the analytical information produced. Water companies have a duty to make the results of their testing available to consumers and the DWI also publishes sum-mary information on individual companies both in an annual report and on its website.
11.2.7 Water safety
The Regulations also make some provisions for drinking water safety. There are specific requirements concerning Cryptosporidium , there is a requirement to adequately treat and disinfect water supplies, and there are controls over chemicals and materials of construction that drinking water supplies might come into contact with.
11.3
Water quality incidents
11.3.1 Incident notification
When events occur that might impact on the quality or sufficiency of the water supplied, water companies are required to notify such events to the DWI under the terms set out in the Water Industry (Supplier’s Information) Direction 2009 (DWI 2009a ). This duty is enforceable under Section 202 of the Water Industry Act 1991 .
The Direction requires water companies to inform the DWI of all events that have affected, or are likely to affect, drinking water quality or sufficiency of supplies where, as a result, there may be a risk to consumers’ health (Box 11.1 ). When notified of such events the DWI assesses the water company’s provisional information to determine whether the event is an incident. If the event is deemed to be an incident a full report from the company may also be required.
11.3.2 What should be notified?
The wording of the current Direction and its predecessors deliberately leaves it to water companies to decide what to notify. This is because an event that appears significant to a small company could appear to be less so to a larger company. Furthermore the trigger for consumer contacts may be very different between a rural area and a highly populated inner city area. However, the DWI has issued guidance on the type of events that it considers should be notifiable (DWI 2009b ). The guidance also gives information on the investigation process by which the DWI investigates incidents.
11.3.3 Incident investigation
The DWI assesses the information provided by water companies to determine whether the event meets the criteria of an incident, as defined by the DWI (Box 11.2 ).
Most incidents are relatively minor, but all are assessed thoroughly (Box 11.3 ) and may result in recommendations to the company concerned on the actions needed to minimize the risk of future failures. Where the lessons to be learnt might benefit other companies, generic guidance may be issued to the industry. Consideration is given to whether during the incident the company contravened any of the wholesomeness standards set out in the Regulations. The DWI also considers whether the company contravened any other enforceable regulatory duty. If contraventions occurred, the DWI then decides whether the breaches were trivial or likely to recur and whether enforcement action under Section 18 of the Water Industry Act 1991 is required.