{
  "url": "https://openlegislation.uk/water-supply-water-quality-regulations-northern-ireland-2017/schedule-3/paragraph-1",
  "json_url": "https://openlegislation.uk/water-supply-water-quality-regulations-northern-ireland-2017/schedule-3/paragraph-1.json",
  "legislation": "nisr/2017/212",
  "legislation_title": "The Water Supply (Water Quality) Regulations (Northern Ireland) 2017",
  "legislation_url": "https://openlegislation.uk/water-supply-water-quality-regulations-northern-ireland-2017",
  "path": "schedule/3/paragraph/1",
  "kind": "paragraph",
  "number": "1",
  "heading": null,
  "text": "(1) A monitoring programme established under Part 4 of these Regulations must—\n(a) verify that—\n(i) the measures in place to control risks to human health throughout the water supply chain (from the catchment area through abstraction, treatment and storage to distribution) are working effectively; and\n(ii) water at the point of compliance is wholesome;\n(b) provide information on the quality of water supplied to—\n(i) demonstrate whether or not the water complies with prescribed concentrations and values for parameters in Schedule 1;\n(ii) determine the organoleptic and microbiological quality of the water; and\n(iii) establish the effectiveness of the treatment of the water, particularly of disinfection where it is used.\n(c) identify the most appropriate means of mitigating any risk to human health; and\n(d) have regard to Part 5.\n(2) A monitoring programme must consist of either—\n(a) the collection and analysis of discrete water samples; or\n(b) measurement recorded by a continuous monitoring process; or\n(c) a combination of both of the methods described in sub-paragraphs (a) and (b).\n(3) In addition, monitoring programmes may consist of—\n(a) inspections of records of the functionality and maintenance status of equipment; and/or\n(b) inspections of the catchment area, water abstraction, treatment, storage and distribution infrastructure.\n(4) The monitoring programme may be based on a risk assessment as set out in regulation 30.\n(5) When choosing appropriate parameters and other micro-organisms, parasites or substances for monitoring programmes, local conditions for each water supply system must be taken into consideration.\nTABLE 1\nPARAMETERS AND CIRCUMSTANCES FOR GROUP A MONITORING\n1 A supply which consists of both groundwater and surface water is deemed to be a supply which consists only of surface water.\n(1) Item\n(2) Parameter\n(3) Circumstances\n1\nAluminium\nIf used as water treatment chemicals or where the water originates from, or is influenced by, surface waters\n2\nAmmonium\nWhere chloramination is practised\n3\nColiform bacteria\nIn all supplies\n4\nColony Counts\nIn all supplies\n5\nColour\nIn all supplies\n6\nConductivity\nIn all supplies\n7\nDisinfectant residual\nWhen disinfection treatment is practised\n8\nEscherichia coli (E. coli)\nIn all supplies\n9\nIndicative Dose\nWhere there is treatment in place to reduce the level of radionuclides in water intended for human consumption.\n10\nIron1\nIf used as water treatment chemicals or where the water originates from, or is influenced by, surface waters\n11\nManganese1\nWhere the water originates from, or is influenced by, surface waters\n12\nNitrate\nWhere chloramination is practised\n13\nNitrite\nWhere chloramination is practised\n14\nOdour\nIn all supplies\n15\npH (Hydrogen ion)\nIn all supplies\n16\nRadon\nWhere there is treatment in place to reduce the level of radionuclides in water intended for human consumption.\n17\nTaste\nIn all supplies\n18\nTritium\nWhere there is treatment in place to reduce the level of radionuclides in water intended for human consumption.\n19\nTurbidity\nIn all supplies\nTABLE 2\nAnnual Sampling Frequencies: Water Supply Zones\nThis table sets out the annual sampling frequencies for all the substances and parameters in column 1. These are determined for each water supply zone according to its estimated population (column 2).\n1 Where the population is not an exact multiple of 5,000, the population figure should be rounded up to the nearest multiple of 5,000.\n2 Sampling for these parameters may be within water supply zones or at supply points as specified in Table 3, subject to notes (5) and (6) below.\n3 Group A monitoring in water supply zones is required only where chloramination is practised. In other circumstances Group B monitoring is required.\n4 Group B monitoring in water supply zones is required only where sodium hypochlorite is added after water has left the treatment works. In other circumstances, Group B monitoring is required at supply points.\n5 To monitor for indicative dose (for radioactivity).\n6 In the event that a single sample is taken in a year, a further sample should be taken if there is any change in relation to that supply that could affect the concentration of radionuclides in the water supply.\n(1) Substances and parameters subject to monitoring\n(2) Estimated population of water supply zone1\n(3) Number of samples per year\nGroup A monitoring\nEscherichia coli (E. coli)\n< 100\n≥ 100\n4\n12 per 5,000 population1\nColiform bacteria\nResidual disinfectant\nAluminium\n<100\n100–4,999\n5,000–9,999\n10,000–29,999\n30,000–49,999\n50,000–79,999\n80,000–100,000\n2\n4\n12\n24\n36\n52\n76\nAmmonium\nColony counts\nColour\nConductivity2\nHydrogen ion\nIron\nManganese\nNitrate3\nNitrite3\nOdour\nTaste\nTurbidity\nGroup B monitoring\nAluminium\n<100\n100–4,999\n5,000–100,000\n1\n4\n8\nAntimony\nArsenic\nBenzene2\nBenzo(a)pyrene\nBoron2\nBromate4\nCadmium\nChromium\nClostridium perfringens (including spores)\nCopper\nCyanide2\n1,2 dichloroethane2\nEnterococci\nFluoride2\nGross alpha25\nGross beta25\nIron\nLead\nManganese\nMercury2\nNickel\nNitrate3\nNitrite3\nPesticides and related\nproducts2\nPolycyclic aromatic hydrocarbons\nRadon26\nSelenium\nSodium\nTrichloroethene/\nTetrachloroethene2\nTetrachloromethane2\nTrihalomethanes\nChloride2\nSulphate2\nTotal organic carbon2\nTritium2\nTABLE 3\nAnnual Sampling Frequencies: Treatment Works or Supply Points\nSampling is at treatment works for the substances and parameters shown in column (1) of the Table as items (1) to (6) and at supply points for the other substances and parameters, except nitrite subject to notes 2 and 3 to the Table below. This table sets out the annual sampling frequencies for all the substances and parameters in column 2 at treatment works or supply points. The frequencies are determined according to the volume of water supplied at each treatment works or supply point (column 3).\n1 The water undertaker may use the number of inhabitants in a supply zone instead of the volume of water to determine the minimum frequency, assuming a water consumption of 200 l/day/capita.\n2 The volumes are calculated as averages taken over a calendar year.\n3 Sampling at treatment works when chloramination is practised.\n4 Sampling at treatment works when chloramination is not practised.\n5 Group B monitoring at supply points is required only where sodium hypochlorite is not added after water has left the treatment works. In other circumstances, Group B monitoring is required in water supply zones\n6 To monitor for indicative dose (for radioactivity).\n(1) Item\n(2) Substances and parameters\n(3) Volume of water supplied m3/d1\n(4) Number of samples per year2\n1\nEscherichia coli (E. coli)\n<20\n20-1,999\n2,000-5,999\n6,000-11,999\n≥ 12,000\n4\n52\n104\n208\n365\n2\nColiform bacteria\n3\nColony counts\n4\nNitrite3\n5\nResidual disinfectant\n6\nTurbidity\nGroup A monitoring\n7\nConductivity\n<20\n20-999\n1,000-1,999\n2,000-5,999\n6,000-9,999\n10,000-15,999\n16,000-32,999\n33,000-49,999\n50,000-67,999\n68,000-84,999\n85,000-101,999\n102,000-119,999\n120,000-241,999\n242,000-484,999\n485,000-728,999\n2\n4\n12\n24\n36\n52\n104\n156\n208\n260\n312\n365\n730\n1,460\n2,190\nGroup A monitoring\n8\nGross alpha6\n<20\n20-999\n1,000-49,999\n50,000-89,999\n90,000-299,999\n300,000-649,999\n≥ 650,000\n1\n4\n8\n12\n24\n36\n48\n9\nGross beta6\n10\nRadon\n11\nTritium\nGroup B monitoring\n12\nBenzene\n<20\n20-999\n1,000-49,999\n50,000-89,999\n90,000-299,999\n300,000-649,999\n≥650,000\n1\n4\n8\n12\n24\n36\n48\n13\nBoron\n14\nBromate5\n15\nClostridium perfringens (including spores)\n16\nCyanide\n17\n1,2,dichloroethane\n18\nFluoride\n19\nMercury\n20\nNitrite4\n21\nPesticides and related products\n22\nTrichloroethene/\nTetrachloroethene\n23\nTetrachloromethane\n24\nChloride\n25\nSulphate\n26\nTotal Organic Carbon\n27\nRadon\n28\nTritium\n29\nGross alpha6\n30\nGross beta6",
  "extent": null,
  "status": null,
  "version": "current",
  "annotations": [],
  "outstanding_effects": [],
  "provenance": {
    "source": "legislation.gov.uk",
    "source_url": "https://www.legislation.gov.uk/nisr/2017/212/schedule/3/paragraph/1",
    "retrieved_at": "2026-10-29T00:51:01.047970+00:00"
  },
  "licence": "Open Government Licence v3.0",
  "licence_url": "https://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/",
  "attribution": "Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives."
}