{
  "url": "https://openlegislation.uk/private-water-supplies-england-regulations-2016/regulation-16",
  "json_url": "https://openlegislation.uk/private-water-supplies-england-regulations-2016/regulation-16.json",
  "legislation": "uksi/2016/618",
  "legislation_title": "The Private Water Supplies (England) Regulations 2016",
  "legislation_url": "https://openlegislation.uk/private-water-supplies-england-regulations-2016",
  "path": "regulation/16",
  "kind": "regulation",
  "number": "16",
  "heading": "Investigations",
  "text": "(1) A local authority must carry out an investigation to establish the cause if it suspects that a private water supply is unwholesome or that an indicator parameter does not comply with the concentrations or values prescribed in Part 2 or 3 of Schedule 1.\n(2) Once a local authority has carried out an investigation and established the cause of the water being unwholesome, it must act in accordance with paragraphs (3), (4) and (6) as appropriate.\n(3) If the cause of the water being unwholesome is due to the distribution system within a domestic premises (whether or not the water is made available to the public in those premises), the local authority must promptly inform the people likely to be affected and offer them advice on measures necessary for the protection of human health.\n(4) In addition to the duty in paragraph (3) (where it applies), if the cause of the water being unwholesome is due to the circumstances described in paragraph (5), the local authority must—\n(a) if the water is a potential danger to human health and the conditions in regulation 18 are fulfilled, serve a notice under that regulation, or\n(b) within 28 days of establishing the cause and if appropriate remedial action has not been taken, serve a notice in accordance with section 80 of the Act (remedial powers of local authorities in relation to private supplies) unless the local authority grants an authorisation in accordance with regulation 17(2).\n(5) The circumstances in this paragraph are—\n(a) if the cause of the water being unwholesome is due to the distribution system within domestic premises where water is made available to the public;\n(b) if the cause of the water being unwholesome is not due the distribution system within domestic premises.\n(6) In any case where the monitoring obligations in respect of a private water supply have been reduced or otherwise varied under Part 2A of Schedule 2 by a local authority and—\n(a) the local authority considers there to be a significant risk that a private water supply is unwholesome; or\n(b) the local authority determines as a matter of fact that a private water supply is unwholesome,\nthe reduction or variation in respect of the parameter which has contributed to the risk or fact of unwholesomeness must cease immediately and the standard frequency outlined in Table 2 or Table 3 in Schedule 2 (as applicable) must be reinstated in respect of that parameter.",
  "extent": "E+W+S+N.I.",
  "status": null,
  "version": "current",
  "annotations": [
    {
      "type": "F",
      "label": "F1",
      "text": "Words in reg. 16(2) substituted (11.7.2018) by The Private Water Supplies (England) (Amendment) Regulations 2018 (S.I. 2018/707), regs. 1(1), 2(7)(a) (with reg. 3)"
    },
    {
      "type": "F",
      "label": "F2",
      "text": "Words in reg. 16(4)(b) substituted (11.7.2018) by The Private Water Supplies (England) (Amendment) Regulations 2018 (S.I. 2018/707), regs. 1(1), 2(7)(b) (with reg. 3)"
    },
    {
      "type": "F",
      "label": "F3",
      "text": "Reg. 16(6) inserted (11.7.2018) by The Private Water Supplies (England) (Amendment) Regulations 2018 (S.I. 2018/707), regs. 1(1), 2(7)(c) (with reg. 3)"
    }
  ],
  "outstanding_effects": [],
  "provenance": {
    "source": "legislation.gov.uk",
    "source_url": "https://www.legislation.gov.uk/uksi/2016/618/regulation/16",
    "retrieved_at": "2026-10-28T23:23:04.925081+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."
}