{
  "url": "https://openlegislation.uk/water-supply-water-quality-regulations-2000/schedule-3",
  "json_url": "https://openlegislation.uk/water-supply-water-quality-regulations-2000/schedule-3.json",
  "legislation": "uksi/2000/3184",
  "legislation_title": "The Water Supply (Water Quality) Regulations 2000",
  "legislation_url": "https://openlegislation.uk/water-supply-water-quality-regulations-2000",
  "path": "schedule/3",
  "kind": "schedule",
  "number": "3",
  "heading": "MONITORING",
  "text": "TABLE 1\nPARAMETERS AND CIRCUMSTANCES FOR CHECK MONITORING\n(1)\n(2)\n(3)\nItem\nParameter\nCircumstances\n1.\nAluminium\nWhen used as flocculant or where the water originates from, or is influenced by, surface waters\n2.\nAmmonium\n3.\nClostridium perfringens (including spores)\nWhere the water originates from, or is influenced by, surface waters\n4.\nColiform bacteria\n5.\nColour\n6.\nConductivity\n7.\nEscherichia coli (E. coli)\n8.\nHydrogen ion concentration\n9.\nIron\nWhen used as flocculant or where the water originates from, or is influenced by, surface waters\n10.\nManganese\nWhere the water originates from, or is influenced by, surface waters\n11.\nNitrate\nWhen chloramination is practised\n12.\nNitrite\nWhen chloramination is practised\n13.\nOdour\n14.\nTaste\n15.\nTurbidity\nTABLE 2\nANNUAL SAMPLING FREQUENCIES: WATER SUPPLY ZONES\n(1)\n(2)\n(3)\n(4)\nSubstances and parameters subject to check monitoring\nEstimated population of water supply zone\nReduced\nStandard\nNotes: *Sampling for these parameters may be within water supply zones or at supply points as specified in Table 3, subject to notes (ii) and (iii) below.\n(i)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.\n(ii)Check monitoring in water supply zones is required only where chloramination is practised. In other circumstances audit monitoring is required.\n(iii)Audit monitoring in water supply zones is required only where sodium hypochlorite is added after water has left the treatment works. In other circumstances, audit monitoring is required at supply points.\n(iv)To monitor for total indicative dose (for radioactivity).\nE. coli\n<100\n4\nColiform bacteria Residual disinfectant\n>–100\n12 per 5,000 population\nAluminium\nAmmonium\nClostridium perfringens\nColony counts\n<100\n1\n2\nColour\n100–4,999\n2\n4\nConductivity\n5,000–9,999\n6\n12\nHydrogen ion\n10,000–29,999\n12\n24\nIron\n30,000–49,999\n18\n36\nManganese\n50,000–79,999\n26\n52\nNitrate\n80,000–99,999\n38\n76\nNitrite\nOdour\nTaste\nTurbidity\nParameters subject to audit monitoring\nAluminium\nAntimony\nArsenic\nBenzene\n<100\n1\nBenzo(a)pyrene\n100–4,999\n4\nBoron\n5,000–99,999\n8\nBromate\nCadmium\nChromium\nCopper\nCyanide\n1,2 dichloroethane\nEnterococci\nFluoride\nIron\nLead\nManganese\nMercury\nNickel\nNitrate\nNitrite\nPesticides and related products\n<100\n1\n100–4,999\n4\nPolycyclic aromatic hydrocarbons\n5,000–99,999\n8\nSelenium\nSodium\nTrichloroethene/Tetrachloroethene\nTrihalomethanes\nChloride\nSulphate\nTotal organic carbon\nTritium\nGross alpha\nGross beta\nTABLE 3\nANNUAL SAMPLING FREQUENCIES: TREATMENT WORKS OR SUPPLY POINTS\n(1)\n(2)\n(3)\n(4)\n(5)\nItem\nSubstances and parameters\nVolume of water supplied m3/d\nReduced\nStandard\nNotes: *Sampling 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, subject to notes (ii) and (iii) below.\n(i)Check monitoring is required only in respect of surface waters (see regulation 6(2) and Table 1 in Schedule 3).\n(ii)Check monitoring at treatment works is required only when chloramination is practised. In other circumstances, audit monitoring is required.\n(iii)Audit monitoring at supply points is required only where sodium hypochlorite is not added after water has left the treatment works. In other circumstances, audit monitoring is required in water supply zones.\n(iv)To monitor for total indicative dose (for radioactivity).\n1.\nE. coli\n<20\n4\n2.\nColiform bacteria\n20–1,999\n12\n52\n3.\nColony counts\n2,000–5,999\n52\n104\n4.\nNitrite\n6,000–11,999\n104\n208\n5.\nResidual disinfectant\n>12,000\n104\n365\n6.\nTurbidity\nSubject to check monitoring\n7.\nClostridium perfringens\n<20\n2\n20–999\n2\n4\n8.\nConductivity\n1,000–1,999\n6\n12\n2,000–5,999\n12\n24\n6,000–9,999\n18\n36\n10,000–15,999\n26\n52\n16,000–32,999\n52\n104\n33,000–49,999\n78\n156\n50,000–67,999\n104\n208\n68,000–84,999\n130\n260\n85,000–101,999\n156\n312\n102,000–119,999\n183\n365\n120,000–241,999\n365\n730\n242,000–484,999\n730\n1,460\n485,000–728,999\n1,095\n2,190\nSubject to audit monitoring\n9.\nBenzene\n10.\nBoron\n11.\nBromate\n12.\nCyanide\n13.\n1,2 dichloroethane\n14.\nFluoride\n15.\nMercury\n<20\n1\n16.\nNitrite\n20–999\n4\n17.\nPesticides and\n1,000–49,999\n8\nrelated products\n50,000–89,999\n12\n90,000–299,999\n24\n300,000–649,999\n36\n18.\nTrichloroethene/Tetrachloroethene\n>–650,000\n48\n19.\nTetrachloromethane\n20.\nChloride\n21.\nSulphate\n22.\nTotal organic carbon\n23.\nTritium\n24.\nGross alpha\n25.\nGross beta",
  "extent": null,
  "status": null,
  "version": "current",
  "annotations": [
    {
      "type": "footnote",
      "label": "f1",
      "text": "(i)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."
    },
    {
      "type": "footnote",
      "label": "f2",
      "text": "*Sampling for these parameters may be within water supply zones or at supply points as specified in Table 3, subject to notes (ii) and (iii) below."
    },
    {
      "type": "footnote",
      "label": "f3",
      "text": "(ii)Check monitoring in water supply zones is required only where chloramination is practised. In other circumstances audit monitoring is required."
    },
    {
      "type": "footnote",
      "label": "f4",
      "text": "(iii)Audit monitoring in water supply zones is required only where sodium hypochlorite is added after water has left the treatment works. In other circumstances, audit monitoring is required at supply points."
    },
    {
      "type": "footnote",
      "label": "f5",
      "text": "(iv)To monitor for total indicative dose (for radioactivity)."
    },
    {
      "type": "footnote",
      "label": "f6",
      "text": "*Sampling 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, subject to notes (ii) and (iii) below."
    },
    {
      "type": "footnote",
      "label": "f7",
      "text": "(ii)Check monitoring at treatment works is required only when chloramination is practised. In other circumstances, audit monitoring is required."
    },
    {
      "type": "footnote",
      "label": "f8",
      "text": "(i)Check monitoring is required only in respect of surface waters (see regulation 6(2) and Table 1 in Schedule 3)."
    },
    {
      "type": "footnote",
      "label": "f9",
      "text": "(iii)Audit monitoring at supply points is required only where sodium hypochlorite is not added after water has left the treatment works. In other circumstances, audit monitoring is required in water supply zones."
    },
    {
      "type": "footnote",
      "label": "f10",
      "text": "(iv)To monitor for total indicative dose (for radioactivity)."
    }
  ],
  "outstanding_effects": [
    {
      "type": "inserted",
      "affecting": "uksi/2001/2885",
      "affecting_title": "The Water Supply (Water Quality) (Amendment) Regulations 2001"
    },
    {
      "type": "word omitted",
      "affecting": "uksi/2001/2885",
      "affecting_title": "The Water Supply (Water Quality) (Amendment) Regulations 2001"
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      "affecting": "uksi/2001/2885",
      "affecting_title": "The Water Supply (Water Quality) (Amendment) Regulations 2001"
    },
    {
      "type": "words inserted",
      "affecting": "uksi/2001/2885",
      "affecting_title": "The Water Supply (Water Quality) (Amendment) Regulations 2001"
    },
    {
      "type": "word substituted",
      "affecting": "uksi/2001/2885",
      "affecting_title": "The Water Supply (Water Quality) (Amendment) Regulations 2001"
    },
    {
      "type": "word substituted",
      "affecting": "uksi/2001/2885",
      "affecting_title": "The Water Supply (Water Quality) (Amendment) Regulations 2001"
    },
    {
      "type": "word substituted",
      "affecting": "uksi/2001/2885",
      "affecting_title": "The Water Supply (Water Quality) (Amendment) Regulations 2001"
    },
    {
      "type": "words substituted",
      "affecting": "uksi/2001/2885",
      "affecting_title": "The Water Supply (Water Quality) (Amendment) Regulations 2001"
    },
    {
      "type": "substituted for Sch. 3 Table 3 Note (ii)",
      "affecting": "uksi/2001/2885",
      "affecting_title": "The Water Supply (Water Quality) (Amendment) Regulations 2001"
    },
    {
      "type": "substituted",
      "affecting": "uksi/2010/991",
      "affecting_title": "The Water Supply Regulations 2010"
    },
    {
      "type": "substituted",
      "affecting": "uksi/2010/991",
      "affecting_title": "The Water Supply Regulations 2010"
    },
    {
      "type": "words inserted",
      "affecting": "uksi/2007/2734",
      "affecting_title": "The Water Supply (Water Quality) Regulations 2000 (Amendment) Regulations 2007"
    },
    {
      "type": "word inserted",
      "affecting": "uksi/2007/2734",
      "affecting_title": "The Water Supply (Water Quality) Regulations 2000 (Amendment) Regulations 2007"
    },
    {
      "type": "words inserted",
      "affecting": "uksi/2007/2734",
      "affecting_title": "The Water Supply (Water Quality) Regulations 2000 (Amendment) Regulations 2007"
    }
  ],
  "provenance": {
    "source": "legislation.gov.uk",
    "source_url": "https://www.legislation.gov.uk/uksi/2000/3184/schedule/3",
    "retrieved_at": "2026-10-29T08:09:45.572380+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."
}