Drinking Water 2003
Annex 3 Definitions and Glossary of Terms These definitions will assist the understanding of the Report where technical terms may have been used   Aesthetic associated with the senses of taste, smell and sight After-growth the growth of micro-organisms within distribution systems Alkali a solution containing an excess of free hydroxyl ions, with a pH greater than seven Aquifer water-containing underground strata Authorities the Secretary of State for the Environment, Transport and the Regions, or the National Assembly for Wales, as the context may require Badenoch Reports the first (1990) and second (1995) reports of the Group of Experts on Cryptosporidium in Water Supplies Biocidal having the property of inactivating pathogens Biofilm naturally-occurring growth of micro-organisms on surfaces inside water mains Bouchier Report the third (1998) report of the Group of Experts on Cryptosporidium in Water Supplies Bulk supply water supplied in bulk, usually in treated form, from one water company to another Chloramination an alternative form of disinfectant based on chlorine and ammonia which provides a longer lasting residual in the distribution system compared to free chlorine Coagulation the process of aggregating colloidal and fine particulate matter into a settleable material Coliforms a group of generally harmless bacteria which may be faecal or environmental in origin Compound a compound consists of two or more elements in chemical combination Compliance assessment a comparison made by the Inspectorate of data gathered by water companies against standards and other regulatory requirements Compliance programme a programme of works required as part of an undertaking Contravention a breach of a regulatory requirement Crohn’s Disease crohn’s disease is an inflammation of the bowel Cryptosporidium a protozoan parasite Determination an analysis for a specific parameter Distribution systems a water company’s network of mains, pipes, pumping stations and service reservoirs through which treated water is conveyed to consumers EC Drinking Water Directive Council Directive 80/778/EEC relating to the quality of water intended for human consumption. (Replaced by Council Directive 98/83/EC in December 1998 – the ‘New Directive’) Enforcement action the means, as set out in the Water Act 1989 and consolidated into the Water Industry Act 1991, by which the Secretary of State requires a water company to comply with certain regulatory requirements Epidemiology a process of studying the distribution of cases of disease within a population in relation to exposure to possible sources of the infection, with a view to establishing the actual source of the infection Epoxy resin relining a rehabilitation process in which a cleaned section of iron water main is sprayed with a mixture of epoxy resin and hardener to produce a thin but strong coating of material on the inside of the main Exceedence Synonym for contravention or breach (see above) Faecal coliforms a sub-group of coliforms, almost exclusively faecal in origin Filtration the separation of suspended particulate matter from a fluid Giardia a protozoan parasite Granular Activated Carbon An adsorbent filtration media used to remove trace organic compounds from water Groundwater Water from aquifers or other underground sources Guidance Document ‘Guidance on Safeguarding the Quality of Public Water Supplies’. HMSO 1989 (ISBN 0 11 752262 7). Improvement programmes Improvement works, associated with undertakings or conditions of regulation 4 relaxations Incident An event affecting or threatening to affect drinking water quality Indicator organism An organism which indicates the presence of contamination and hence the possible presence of pathogens Inspectorate The Drinking Water Inspectorate Key parameters 15 parameters chosen to indicate quality of water in supply zones and to allow comparisons to be made between companies Legal requirements The requirements as specified in the Water Act 1989, now consolidated into the Water Industry Act 1991, and the Regulations made under the Acts Mean zonal percentage compliance see zonal percentage compliance Microbiological associated with the study of microbes Mycobacterium Avium Complex (MAC) a group of bacteria responsible for pulmonary and non-pulmonary infections, particularly in the immuno compromised Mycobacterium Paratuberculosis (MAP) specie of the Mycobacterium Avium Complex (MAC) group of organisms that causes Johne’s disease in cattle m3/d cubic metre per day mg/l milligram per litre (one thousandth of a gram per litre) Ml/d megalitre per day (one Ml/d is equivalent to 1,000 m3/d, or to 220,000 gallon/d) µg/l microgram per litre (one millionth of a gram per litre) ng/l nanogram per litre (one billionth of a gram per litre) New Regulations the Water Supply (Water Quality) Regulations 2000 in England; the Water Supply (Water Quality) Regulations 2001 in Wales Notice of Intention to make a a necessary precursor to the issue of an Enforcement Order Final Order which must be advertised with a minimum of 28 days being allowed for representations or objections to the proposed Order Oocyst the resistant form in which Cryptosporidium occurs in the environment, and which is capable of causing infection Operational Guidelines and Code ‘In situ Epoxy Resin Lining – Operational Guidelines and Code of of Practice (OGCP) Practice. A source document for the Water Mains Rehabilitation Manual’. I C Warren. WRc 1989 Operational performance index the average of the mean zonal compliance for each of the six parameters most reflecting the operation and maintenance of treatment works and distribution systems Outbreak Control Team (OCT) a team set up to investigate possible waterborne outbreaks of cryptosporidiosis, comprising members of the medical profession, as well as representatives of relevant local authorities and water companies Overall quality index the average of the mean zonal compliance for each of the 15 key parameters Ozone process the application of ozone gas in drinking water treatment Parameters The substances, organisms and properties listed in Schedule 2 and regulation 3 of the Regulations. Parameter definitions can be found in the Introduction to Part 2 of this Report. Pathogen an organism which can cause disease PCV see ‘Prescribed concentration or value’ Pesticides any fungicide, herbicide or insecticide or related product (excluding medicines) used for the control of pests or diseases pH value a measure of the acidity or basicity related to the concentration of the hydrogen ion Plumbosolvency the tendency for lead to dissolve in water Polycyclic aromatic hydrocarbons the presence of PAH in drinking water is usually associated with (PAH) pre-1970s distribution mains that were lined with coal tar to prevent corrosion. The concentrations found are not of significance of health. Pre- and post-renovation a programme of assessment before and after mains renovation assessment (PPRA) to demonstrate justification for the work, and the improvements achieved by the renovation Prescribed concentration or value the numerical value assigned to water quality standards defining (PCV) the maximal or minimal legal concentration or value of a parameter. In certain circumstances, the PCV may be authorised by the Secretary of State under regulation 4 to be relaxed to a specified extent – see 'Relaxation' Principles of Water Supply Hygiene a booklet identifying principles to be considered when and Technical Guidance Notes developing procedures for safeguarding water supplies against contamination and guidance on development of such procedures – published by Water UK, October 1998 Private supplies water taken from private sources or supplied by non-licensed suppliers; supplies of water provided otherwise than by a statutorily appointed water undertaker Protozoan Parasites a single cell organism that can only survive by infecting a host Public Record the information made available to the public as required by regulations 29 and 30 Public supplies water supplied by a company licensed for that purpose Regulations The Water Supply (Water Quality) Regulations 1989, as amended, made under the Act or, in the case of private water supplies, the Private Water Supplies Regulations 1991 Regulatory requirements see 'Legal requirements' Relaxation a relaxation of the standards according to regulations 4 and 5 – subject in most cases to the completion of improvement works – in emergencies or as a result of exceptional meteorological conditions or by reason of the nature and structure of the ground from which the supply emanates Remedial Action action taken to improve a situation Secretary of State the Secretary of State for the Environment, Transport and the Regions Service reservoir a water tower, tank or other reservoir used for the storage of treated water within the distribution system Sodium Chloride a chemical commonly known as table salt Springs groundwater appearing at the surface at the outcrop of the junction of a permeable with an impermeable stratum Standards the prescribed concentrations or values listed in Schedule 2, Tables A to E and regulation 3 of the Regulations Steroid a fat-soluble organic compound found in living organisms Supply point a point other than a consumer's tap authorised for the taking of samples for compliance with the Regulations Surface water water from rivers, impounding reservoirs or other surface water source Technical audit the means of checking that water companies are complying with their statutory obligations Time of supply the moment when water passes from the water company's pipework into a consumer's pipework Trihalomethanes (THMs) a group of compounds, formed during the disinfection process by the reaction between chlorine and naturally occurring organic substances present in water. The detection of THMs is indicative of the likely presence of other disinfection by products Toxicology the study of the health effects of substances Treated water water treated for use for domestic purposes as defined in the Regulations Undertaking a legally binding programme of work to take appropriate steps to secure or restore compliance with regulatory duties; given by a water company to the Secretary of State for the purposes of section 19(1)(b) of the Water Industry Act 1991 Water supply zone a pre-defined area of supply for establishing sampling frequencies, compliance with standards and information to be made publicly available Websites location of information on the Internet – the DWI website is http://www.dwi.defra.gov.uk WHO World Health Organization Wholesome/Wholesomeness a concept of water quality which is defined by reference to standards and other requirements set out in the Regulations WRc Water Research Centre (1989) plc and/or, as the context may require, its predecessor body Zonal percentage compliance the percentage of results for a specific parameter which complied with the PCV – the mean zonal percentage compliance is the average of the zonal percentage compliances of every one of a company’s zones

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