{"name":"Untap rules: surface water drainage charges by water company, 2026-27","description":"The household surface water drainage charge for each of the 11 water and sewerage companies in England and Wales in 2026-27, which is what a household saves each year if its rainwater does not drain to a public sewer. Includes how far back each company backdates a rebate and where to apply, read from each company’s own charges scheme.","url":"https://untap.money/open-data#water-surface-drainage-charges","guide":"https://untap.money/guides/water-surface-drainage-rebate","licence":"https://creativecommons.org/licenses/by/4.0/","publisher":"Untap","date_published":"2026-08-16","last_changed":"2026-08-16","csv":"https://untap.money/open-data/rules/water-surface-drainage-charges.csv","json":"https://untap.money/open-data/rules/water-surface-drainage-charges.json","sources":[{"name":"Each company’s own household charges scheme, linked per row","url":"https://untap.money/guides/water-surface-drainage-rebate"}],"columns":[{"name":"company","description":"Water and sewerage company"},{"name":"charging_year","description":"Year the figures apply to, 1 April to 31 March"},{"name":"rebate_name","description":"What the company calls the rebate"},{"name":"charge_type","description":"flat, banded (by property type), by-meter (metered and unmetered differ) or standing-charge-difference (no separate line)"},{"name":"charge_summary","description":"The published charge in words"},{"name":"lowest_annual_gbp","description":"Lowest published yearly figure. Empty where the company publishes no comparable figure"},{"name":"highest_annual_gbp","description":"Highest published yearly figure. Empty where the company publishes no comparable figure"},{"name":"basis","description":"How the charge is worked out"},{"name":"backdating","description":"How far back a rebate goes"},{"name":"backdating_years","description":"Backdating in years, measured at the start of 2026-27 for companies that use a fixed date"},{"name":"apply_url","description":"Where to apply. Empty where the company publishes no online route"},{"name":"charges_scheme_url","description":"The company’s own 2026-27 charges scheme"},{"name":"guide_url","description":"Untap’s page for this company"}],"rows":[{"company":"Anglian Water","charging_year":"2026-27","rebate_name":"surface water drainage exemption","charge_type":"flat","charge_summary":"£52.00 a year","lowest_annual_gbp":52,"highest_annual_gbp":52,"basis":"Fixed charge, metered and unmetered alike","backdating":"6 years","backdating_years":6,"apply_url":"https://www.anglianwater.co.uk/services/extra-support/tariff-options/sewerage-charges/surface-water-drainage","charges_scheme_url":"https://www.anglianwater.co.uk/siteassets/household/account--bill/household-charges-scheme-2026-2027.pdf","guide_url":"https://untap.money/guides/water-surface-drainage-rebate/anglian-water"},{"company":"Northumbrian Water","charging_year":"2026-27","rebate_name":"reduced charge for surface water drainage","charge_type":"flat","charge_summary":"£78.70 a year","lowest_annual_gbp":78.7,"highest_annual_gbp":78.7,"basis":"Difference between the combined and foul-only fixed charges","backdating":"6 years","backdating_years":6,"apply_url":"https://www.nwl.co.uk/help/charges/surface-water-drainage/","charges_scheme_url":"https://www.nwl.co.uk/globalassets/customer-pdfs/charges-2026/charges-scheme-2026-27---hh-nw.pdf","guide_url":"https://untap.money/guides/water-surface-drainage-rebate/northumbrian-water"},{"company":"Southern Water","charging_year":"2026-27","rebate_name":"surface water rebate","charge_type":"flat","charge_summary":"£50.00 a year","lowest_annual_gbp":50,"highest_annual_gbp":50,"basis":"Fixed charge, unmetered and the smallest meter band","backdating":"6 years","backdating_years":6,"apply_url":"https://www.southernwater.co.uk/help-and-support/surface-water-rebate/","charges_scheme_url":"https://www.southernwater.co.uk/media/a3yagef1/household-charges-scheme-2026-27.pdf","guide_url":"https://untap.money/guides/water-surface-drainage-rebate/southern-water"},{"company":"Thames Water","charging_year":"2026-27","rebate_name":"surface water drainage rebate","charge_type":"flat","charge_summary":"£47.70 a year","lowest_annual_gbp":47.7,"highest_annual_gbp":47.7,"basis":"Flat rebate, stated directly for metered and unmetered households","backdating":"6 years","backdating_years":6,"apply_url":"https://www.thameswater.co.uk/swd","charges_scheme_url":"https://www.thameswater.co.uk/media-library/toecnx2l/charges-scheme-2026-27.pdf","guide_url":"https://untap.money/guides/water-surface-drainage-rebate/thames-water"},{"company":"South West Water","charging_year":"2026-27","rebate_name":"foul and highway drainage tariff","charge_type":"flat","charge_summary":"£33.26 a year","lowest_annual_gbp":33.26,"highest_annual_gbp":33.26,"basis":"Difference between the two sewerage tariffs","backdating":"Back to 1 April 2014","backdating_years":12,"apply_url":null,"charges_scheme_url":"https://www.southwestwater.co.uk/siteassets/documents/charges/household-charges/202627/sww-household-charges-scheme-2026-27.pdf","guide_url":"https://untap.money/guides/water-surface-drainage-rebate/south-west-water"},{"company":"United Utilities","charging_year":"2026-27","rebate_name":"surface water drainage reduction","charge_type":"by-meter","charge_summary":"Metered £105.35 a year, unmetered about 26% off the wastewater charge","lowest_annual_gbp":105.35,"highest_annual_gbp":105.35,"basis":"Capped reduction if metered, a proportion of the bill if not","backdating":"6 years","backdating_years":6,"apply_url":"https://www.unitedutilities.com/help-and-support/wastewater-services/surface-water-drainage/","charges_scheme_url":"https://www.unitedutilities.com/globalassets/documents/pdf/surface-water-drainage---household-2026-27.pdf","guide_url":"https://untap.money/guides/water-surface-drainage-rebate/united-utilities"},{"company":"Dŵr Cymru Welsh Water","charging_year":"2026-27","rebate_name":"surface water rebate","charge_type":"by-meter","charge_summary":"Metered £45.87 a year, unmetered £70.30 a year","lowest_annual_gbp":45.87,"highest_annual_gbp":70.3,"basis":"Standing charge, and it covers highway drainage too","backdating":"Back to 1 April 2021","backdating_years":5,"apply_url":"https://www.dwrcymru.com/en/help-advice/surface-water-rebate","charges_scheme_url":"https://corporate.dwrcymru.com/-/media/project/files/page-documents/corporate/library/our-charges/summary-of-household-charges/summary-of-household-charges-2026-2027.ashx","guide_url":"https://untap.money/guides/water-surface-drainage-rebate/dwr-cymru-welsh-water"},{"company":"Severn Trent Water","charging_year":"2026-27","rebate_name":"surface water drainage rebate","charge_type":"banded","charge_summary":"Detached house £73.44, Semi-detached house £48.96, Other household premises £24.48","lowest_annual_gbp":24.48,"highest_annual_gbp":73.44,"basis":"Banded by property type","backdating":"6 years","backdating_years":6,"apply_url":"https://www.stwater.co.uk/my-supply/wastewater/surface-water-drainage/","charges_scheme_url":"https://www.stwater.co.uk/content/dam/stw/my-account/our-charges/2026/st-end-user-charges-scheme-2026-27-hh.pdf","guide_url":"https://untap.money/guides/water-surface-drainage-rebate/severn-trent-water"},{"company":"Hafren Dyfrdwy","charging_year":"2026-27","rebate_name":"surface water drainage rebate","charge_type":"banded","charge_summary":"Detached house £118.33, Semi-detached house £78.88, Other household premises £39.45","lowest_annual_gbp":39.45,"highest_annual_gbp":118.33,"basis":"Banded by property type","backdating":"6 years","backdating_years":6,"apply_url":"https://www.hdcymru.co.uk/my-account/our-charges/","charges_scheme_url":"https://www.hdcymru.co.uk/content/dam/stw/my-account/our-charges/2026/hd-end-user-charges-scheme-hh-2026-27.pdf","guide_url":"https://untap.money/guides/water-surface-drainage-rebate/hafren-dyfrdwy"},{"company":"Wessex Water","charging_year":"2026-27","rebate_name":"rainwater drainage allowance","charge_type":"standing-charge-difference","charge_summary":"No published figure. Metered households pay £28.00 a year less with the allowance","lowest_annual_gbp":null,"highest_annual_gbp":null,"basis":"No separate charge, only two standing charges to compare","backdating":"Back to 1 April 2020","backdating_years":6,"apply_url":"https://www.wessexwater.co.uk/your-wastewater/rainwater-drainage-allowance","charges_scheme_url":"https://www.wessexwater.co.uk/media/n3lemv5r/household-charges-scheme-2026-27.pdf","guide_url":"https://untap.money/guides/water-surface-drainage-rebate/wessex-water"},{"company":"Yorkshire Water","charging_year":"2026-27","rebate_name":"surface water drainage rebate","charge_type":"flat","charge_summary":"£85.47 a year","lowest_annual_gbp":85.47,"highest_annual_gbp":85.47,"basis":"Standing charge, Band A for sites up to 500 square metres","backdating":"6 years","backdating_years":6,"apply_url":"https://www.yorkshirewater.com/bill-account/how-we-work-out-your-bill/surface-water-drainage/","charges_scheme_url":"https://www.yorkshirewater.com/media/bjcdy5ih/48694_yw_charges-scheme-book_26-27_accessible_aw.pdf","guide_url":"https://untap.money/guides/water-surface-drainage-rebate/yorkshire-water"}]}