{
  "url": "https://openlegislation.uk/bathing-waters-classification-regulations-1991/schedule-3",
  "json_url": "https://openlegislation.uk/bathing-waters-classification-regulations-1991/schedule-3.json",
  "legislation": "uksi/1991/1597",
  "legislation_title": "The Bathing Waters (Classification) Regulations 1991",
  "legislation_url": "https://openlegislation.uk/bathing-waters-classification-regulations-1991",
  "path": "schedule/3",
  "kind": "schedule",
  "number": "3",
  "heading": "QUALITY AND ADDITIONAL SAMPLING REQUIREMENTS",
  "text": "Parameter\nParametric value\nMinimum sampling frequency\nMethods of analysis and inspection\nNotes\n1. Samples may be taken at intervals of four weeks where samples taken in previous years show that the waters are of an appreciably higher standard than that required for the classification in question and the quality of the waters has not subsequently deteriorated and is unlikely to do so.\n2. Samples must be taken in relation to this parameter when there are grounds for suspecting that there has been a deterioration in the quality of the waters or the substance is likely to be present in the waters.\nMicro-biological:\nTotal coliforms\n10,000/100ml\nFortnightly (see Note 1)\nFermentation in multiple tubes. Sub-culturing of the positive tubes on a confirmation medium. Either counting according to MPN (most probable number) or membrane filtration, culturing on an appropriate medium, sub-culturing and identification of the suspect colonies.\nFaecal coliforms\n2,000/100ml\nFortnightly (see Note 1)\nThe incubation temperature is variable according to whether total or faecal coliforms are being investigated.\nSalmonella\nAbsent in 1 litre\n(see Note 2)\nMembrane filtration, culturing on an appropriate medium, sub-culturing and identification of the suspect colonies.\nEntero viruses\nNo plaque forming units in 10 litres\n(see Note 2)\nConcentration (by filtration, flocculation or centrifuging) and confirmation.\nPhysico-chemical:\nPH\n6 to 9\n(see Note 2)\nElectrometry with calibration at pH 7 and 9.\nColour\nNo abnormal change in colour\nFortnightly (see Note 1)\nVisual inspection or photometry with standards on the platinum cobalt scale.\nMineral oils\nNo film visible on the surface of the water and no odour\nFortnightly (see Note 1)\nVisual and olfactory inspection.\nSurface-active substances reacting with methylene blue\nNo lasting foam\nFortnightly (see Note 1)\nVisual inspection.\nPhenols (phenol indices)\nNo specific odour\nFortnightly (see Note 1)\nOlfactory inspection.\n≤0.05 mg/litre (C6H5OH)\n(see Note 2)\nAbsorption spectrophotometry 4-aminoantipyrine (4 AAP)\nTransparency\n1 metre\nFortnightly (see Note 1)\nSecchi’s disc.",
  "extent": null,
  "status": null,
  "version": "current",
  "annotations": [],
  "outstanding_effects": [
    {
      "type": "omitted",
      "affecting": "uksi/2008/1097",
      "affecting_title": "The Bathing Water Regulations 2008"
    }
  ],
  "provenance": {
    "source": "legislation.gov.uk",
    "source_url": "https://www.legislation.gov.uk/uksi/1991/1597/schedule/3",
    "retrieved_at": "2026-10-29T14:41:28.374538+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."
}