{
  "url": "https://openlegislation.uk/surface-waters-classification-regulations-1989/schedule",
  "json_url": "https://openlegislation.uk/surface-waters-classification-regulations-1989/schedule.json",
  "legislation": "uksi/1989/1148",
  "legislation_title": "The Surface Waters (Classification) Regulations 1989",
  "legislation_url": "https://openlegislation.uk/surface-waters-classification-regulations-1989",
  "path": "schedule",
  "kind": "schedule",
  "number": null,
  "heading": "Criteria for the classification of waters",
  "text": "The limits set out below are maxima\n(1)\n(2)\n(3)\n(4)\n(5)\nNo. in Annex II to 75/440/EEC\nParameters\nDW1\nDW2\nDW3\nNote\n(1) The value given is an upper limit set in relation to the mean annual temperature (high and low).\n2\nColoration (after simple filtration) mg/1 Pt Scale\n20\n100\n200\n4\nTemperature °C\n25\n25\n25\n7\nNitrates mg/1 NO3\n50\n50\n50\n8(1)\nFluorides mg/1 F\n1·5\n10\nDissolved iron mg/1 Fe\n0·3\n2\n12\nCopper mg/1 Cu\n0·05\n13\nZinc mg/1 Zn\n3\n5\n5\n19\nArsenic mg/1 As\n0·05\n0·05\n0·1\n20\nCadmium mg/1 Cd\n0·005\n0·005\n0·005\n21\nTotal chromium mg/1 Cr\n0·05\n0·05\n0·05\n22\nLead mg/1 Pb\n0·05\n0·05\n0·05\n23\nSelenium mg/1 Se\n0·01\n0·01\n0·01\n24\nMercury mg/1 Hg\n0·001\n0·001\n0·001\n25\nBarium mg/1 Ba\n0·1\n1\n1\n26\nCyanide mg/1 Cn\n0·05\n0·05\n0·05\n27\nSulphates mg/1 SO4\n250\n250\n250\n31\nPhenols (phenol index) paranitraniline 4 aminoantipyrine mg/1 C6H5OH\n0·001\n0·005;\n0·1\n32\nDissolved or emulsified hydrocarbons (after extraction by petroleum ether) mg/1\n0·05\n0·2\n1\n33\nPolycyclic aromatic hydrocarbons mg/1\n0·0002\n0·0002\n0·001\n34\nTotal pesticides (parathion, BHC, dieldrin) mg/1\n0·001\n0·0025\n0·005\n39\nAmmonia mg/1 NH4\n1·5\n4",
  "extent": null,
  "status": null,
  "version": "current",
  "annotations": [],
  "outstanding_effects": [],
  "provenance": {
    "source": "legislation.gov.uk",
    "source_url": "https://www.legislation.gov.uk/uksi/1989/1148/schedule",
    "retrieved_at": "2026-10-29T15:41:12.606416+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."
}