--- title: "UK Council Soakaway Rules, Water Undertakers & SuDS Policies [2026/27] | SoakawayCalculator.co.uk" source_url: "https://soakawaycalculator.co.uk/councils" retrieved_by: "AnswerRail Edge Engine v1.1.0-parity-v20 (https://answerrail.com)" level_of_detail: "standard" token_payload_reduction: "90.4%" raw_html_bytes: 149852 compiled_body_bytes: 14354 entities_extracted: 7 currency_recall_static_html: "100%" monitored_currency_tokens: 4 faq_answer_recall_static_html: "50%" monitored_faq_answers: 2 link_recall_static_html: "100%" monitored_content_links: 30 rfc_compliance: "RFC 9110" last_verified_at: "2026-10-17T12:56:00.419Z" cache_age_seconds: 0 origin_cache_control: "public, max-age=0, must-revalidate" --- > **Canonical Source:** [https://soakawaycalculator.co.uk/councils](https://soakawaycalculator.co.uk/councils) > > *Local planning authority soakaway standards, statutory water company S106 connection policies, and LLFA climate change allowances across the UK.* ### Organization: SoakawayCalculator.co.uk (UK Drainage & Stormwater Advisory Desk) | Field | Value | | :--- | :--- | | **Organization** | SoakawayCalculator.co.uk (UK Drainage & Stormwater Advisory Desk) | | **Official Website** | https://soakawaycalculator.co.uk | | **Overview** | UK civil engineering & statutory building control advisory desk for stormwater soakaway attenuation and drainage fields. | ### Entity: Soakaway Calculator UK | Property | Detail | | :--- | :--- | | **Type** | WebSite | | **Name** | Soakaway Calculator UK | ### Entity: Soakaway Calculator UK | Property | Detail | | :--- | :--- | | **Type** | WebApplication | | **Name** | Soakaway Calculator UK | ### Entity: UK BRE Digest 365 & Approved Document H3 Soil Infiltration & Rainfall Rates | Property | Detail | | :--- | :--- | | **Type** | Dataset | | **Name** | UK BRE Digest 365 & Approved Document H3 Soil Infiltration & Rainfall Rates | | **Description** | Standardised geotechnical percolation parameters (f, Vp) and 10-year / 30-year design storm depths across UK local planning authorities and soil classifications.... | ### Frequently Asked Questions (FAQ) **Q: How far must a soakaway be from a house foundation?** > A: Under Building Regulations Approved Document Part H3 (paragraph 3.25) and BS EN 752-4, a soakaway must be installed at least 5.0 metres away from any building foundation or habitable structure, and at least 2.5 metres from property boundary lines, to prevent ground destabilisation and structural subsidence. **Q: What is the standard BRE Digest 365 percolation test procedure?** > A: BRE Digest 365 requires excavating a trial pit of representative depth (typically 1.5m to 2.5m) and measuring water fall from 75% full to 25% full depth (t_75-25). The test must be filled and observed three consecutive times to simulate pre-saturated soil conditions. The soil infiltration rate f is calculated as the storage volume V_75-25 divided by effective internal surface area a_p50 multiplied by t_75-25. **Q: What happens if soil percolation test fails due to heavy clay?** > A: If the soil infiltration rate f is less than 1 x 10^-6 m/s (or Vp > 100 s/mm in BS 6297), a conventional soakaway is infeasible and will trigger Building Control failure. Under the statutory Part H3 surface water hierarchy, you are legally entitled to bypass infiltration and apply for a Section 106 connection to a surface water or combined public sewer, or discharge to an attenuation tank with a hydro-brake flow restrictor. ### Step-by-Step Procedure: How to Conduct a BRE Digest 365 Percolation Test for Building Control #### 1. Excavate Trial Pit Excavate a trial pit to the proposed soakaway invert depth (typically 0.3m wide by 1.0m to 2.0m long). Ensure the base is level and not smeared. #### 2. Fill with Water to Inflow Level Fill the trial pit rapidly with clean water to the proposed effective storage level (at least 300mm depth). #### 3. Measure 75% to 25% Drain Time Record the exact time in seconds taken for water to fall from 75% depth to 25% depth (t_75-25). #### 4. Repeat for 3 Consecutive Runs Refill the pit immediately and record times for Run 2 and Run 3 to verify soil infiltration under saturated conditions. ### Entity: UK Local Planning Authorities & Water Undertakers SuDS Directory | Property | Detail | | :--- | :--- | | **Type** | CollectionPage | | **Name** | UK Local Planning Authorities & Water Undertakers SuDS Directory | | **Description** | Statutory soakaway design criteria, design storm return periods, and sewer connection policies across 20 major UK councils.... | UK LOCAL AUTHORITIES & SUDS HIERARCHY (20 HUBS) # UK Councils, Water Undertakers & SuDS Policy Directory Planning policy criteria, Lead Local Flood Authority (LLFA) climate change uplift requirements, and statutory sewer undertaker Section 106 connection policies across 20 key UK jurisdictions. UK Authority Drainage Standards & Water Undertaker Policy | Council / LPA | Region | Water Authority | Design Storm & CC | Clay Prevalence | Action | | --- | --- | --- | --- | --- | --- | | [Birmingham City Council](/councils/birmingham) | West Midlands | Severn Trent Water | 1-in-30y +40% | Medium | [Council Rules →](/councils/birmingham) | | [Leeds City Council](/councils/leeds) | Yorkshire | Yorkshire Water | 1-in-30y +40% | Medium | [Council Rules →](/councils/leeds) | | [Manchester City Council](/councils/manchester) | North West | United Utilities | 1-in-30y +45% | High | [Council Rules →](/councils/manchester) | | [Bristol City Council](/councils/bristol) | South West | Wessex Water | 1-in-30y +40% | Medium | [Council Rules →](/councils/bristol) | | [Sheffield City Council](/councils/sheffield) | Yorkshire | Yorkshire Water | 1-in-30y +40% | Low | [Council Rules →](/councils/sheffield) | | [Newcastle City Council](/councils/newcastle) | North East | Northumbrian Water | 1-in-30y +40% | Medium | [Council Rules →](/councils/newcastle) | | [Liverpool City Council](/councils/liverpool) | North West | United Utilities | 1-in-30y +40% | Medium | [Council Rules →](/councils/liverpool) | | [Nottingham City Council](/councils/nottingham) | East Midlands | Severn Trent Water | 1-in-30y +40% | Low | [Council Rules →](/councils/nottingham) | | [Surrey County Council](/councils/surrey) | South East | Thames Water | 1-in-30y +40% | High | [Council Rules →](/councils/surrey) | | [Kent County Council](/councils/kent) | South East | Southern Water | 1-in-30y +40% | Medium | [Council Rules →](/councils/kent) | | [Essex County Council](/councils/essex) | East of England | Anglian Water | 1-in-30y +40% | High | [Council Rules →](/councils/essex) | | [Hertfordshire County Council](/councils/hertfordshire) | East of England | Thames Water & Affinity Water | 1-in-30y +40% | Medium | [Council Rules →](/councils/hertfordshire) | | [Cornwall Council](/councils/cornwall) | South West | South West Water | 1-in-30y +45% | Low | [Council Rules →](/councils/cornwall) | | [Cheshire East Council](/councils/cheshire-east) | North West | United Utilities | 1-in-30y +40% | High | [Council Rules →](/councils/cheshire-east) | | [Wiltshire Council](/councils/wiltshire) | South West | Wessex Water | 1-in-30y +40% | Low | [Council Rules →](/councils/wiltshire) | | [Hampshire County Council](/councils/hampshire) | South East | Southern Water | 1-in-30y +40% | Low | [Council Rules →](/councils/hampshire) | | [Oxfordshire County Council](/councils/oxfordshire) | South East | Thames Water | 1-in-30y +40% | Medium | [Council Rules →](/councils/oxfordshire) | | [Cambridgeshire County Council](/councils/cambridgeshire) | East of England | Anglian Water | 1-in-30y +40% | High | [Council Rules →](/councils/cambridgeshire) | | [Cardiff Council / Cyngor Caerdydd](/councils/cardiff) | Wales | Dŵr Cymru Welsh Water | 1-in-100y +40% | Medium | [Council Rules →](/councils/cardiff) | | [City of Edinburgh Council](/councils/edinburgh) | Scotland | Scottish Water | 1-in-30y +40% | Medium | [Council Rules →](/councils/edinburgh) | ## Local Authority Drainage Guides - **[Birmingham City Council](/councils/birmingham)** — West MidlandsSevern Trent WaterRequires BRE 365 calculation sheets with signed site tester certificates for all building control sign-offs.Storm: 1-in-30yr (+40%)Policy → - **[Leeds City Council](/councils/leeds)** — YorkshireYorkshire WaterGlacial till and Coal Measures require 3 full test cycles. Half-empty time must not exceed 24 hours.Storm: 1-in-30yr (+40%)Policy → - **[Manchester City Council](/councils/manchester)** — North WestUnited UtilitiesHigh rainfall region. Requires minimum +45% climate change surge factor for all new surface catchments.Storm: 1-in-30yr (+45%)Policy → - **[Bristol City Council](/councils/bristol)** — South WestWessex WaterMercia Mudstone and limestone fissures. 5m setback from buildings strictly enforced.Storm: 1-in-30yr (+40%)Policy → - **[Sheffield City Council](/councils/sheffield)** — YorkshireYorkshire WaterSteep hillside topography requires overland flow route analysis and minimum 3m boundary setback.Storm: 1-in-30yr (+40%)Policy → - **[Newcastle City Council](/councils/newcastle)** — North EastNorthumbrian WaterBoulder clay and coal mining legacy. Coal Authority mining search required for deep borehole soakaways.Storm: 1-in-30yr (+40%)Policy → - **[Liverpool City Council](/councils/liverpool)** — North WestUnited UtilitiesTriassic sandstone provides good drainage in south; glacial clays predominate towards north.Storm: 1-in-30yr (+40%)Policy → - **[Nottingham City Council](/councils/nottingham)** — East MidlandsSevern Trent WaterSherwood Sandstone provides high permeability; verify absence of historic caves or cellar cavities nearby.Storm: 1-in-30yr (+40%)Policy → - **[Surrey County Council](/councils/surrey)** — South EastThames WaterLondon Clay in north, Weald Clay in south, Greensand ridge in centre. Clay waiver packs frequently required.Storm: 1-in-30yr (+40%)Policy → - **[Kent County Council](/councils/kent)** — South EastSouthern WaterNorth Downs chalk requires 10m sinkhole setback; Wealden clay sections require waiver dossiers.Storm: 1-in-30yr (+40%)Policy → - **[Essex County Council](/councils/essex)** — East of EnglandAnglian WaterHigh prevalence of London Clay. Soakaway failure rate exceeds 75% in southern and central Essex.Storm: 1-in-30yr (+40%)Policy → - **[Hertfordshire County Council](/councils/hertfordshire)** — East of EnglandThames Water & Affinity WaterChalk overlain with Clay-with-Flints. Deep trial pits required to confirm whether chalk aquifer is accessible.Storm: 1-in-30yr (+40%)Policy → - **[Cornwall Council](/councils/cornwall)** — South WestSouth West WaterGranite and slate formations. High seasonal rainfall; 100-year plus 45% storm verification often requested.Storm: 1-in-30yr (+45%)Policy → - **[Cheshire East Council](/councils/cheshire-east)** — North WestUnited UtilitiesGlacial drift and Mercia Mudstone cause widespread percolation failures. Clay exemption forms standard.Storm: 1-in-30yr (+40%)Policy → - **[Wiltshire Council](/councils/wiltshire)** — South WestWessex WaterSalisbury Plain chalk delivers exceptional percolation; ensure groundwater table clearance of >= 1.0m.Storm: 1-in-30yr (+40%)Policy → - **[Hampshire County Council](/councils/hampshire)** — South EastSouthern WaterHigh chalk coverage in north; alluvial clays near coastal harbours. Soakaways standard across 80% of county.Storm: 1-in-30yr (+40%)Policy → - **[Oxfordshire County Council](/councils/oxfordshire)** — South EastThames WaterOxford Clay in valley requires waiver packs; Cotswold limestone in west drains freely.Storm: 1-in-30yr (+40%)Policy → - **[Cambridgeshire County Council](/councils/cambridgeshire)** — East of EnglandAnglian WaterGault Clay and Fenland peat. High water table. IDB consent often required for ditch discharges.Storm: 1-in-30yr (+40%)Policy → - **[Cardiff Council / Cyngor Caerdydd](/councils/cardiff)** — WalesDŵr Cymru Welsh WaterSchedule 3 of Flood and Water Management Act 2010 is active in Wales. Mandatory SAB approval required for any construction > 100m².Storm: 1-in-100yr (+40%)Policy → - **[City of Edinburgh Council](/councils/edinburgh)** — ScotlandScottish WaterScottish Building Standards Technical Handbook Section 3 (Environment). SuDS mandatory for all surface water.Storm: 1-in-30yr (+40%)Policy → NAVRE NEXT-ACTION WALL • BAYESIAN ROUTER ## Recommended Next Statutory Steps & Sister Approvals Automatically ranked for your extension, driveway, or drainage project across the UK statutory compliance network. navre\_bayesian UK Extension & Structural Compliance Suite (NAVRE Network): [RSJCalculator.co.uk ↗](https://rsjcalculator.co.uk "BS EN 1993 Steel Beam & Padstone Sizer")[BuildOverAgreement.co.uk ↗](https://buildoveragreement.co.uk "Part H4 Build-Over Sewer Checker")[PartyWallChecker.co.uk ↗](https://partywallchecker.co.uk "Party Wall Act 1996 3m/6m Notice Checker")[DroppedKerbCalculator.co.uk ↗](https://droppedkerbcalculator.co.uk "Section 184 Vehicle Crossover Estimator")[GardenOfficePower.co.uk ↗](https://gardenofficepower.co.uk "BS 7671 SWA Armour Cable Calculator")[HedgeHeight.co.uk ↗](https://hedgeheight.co.uk "BRE Part 8 Action Hedge Height Calculator") OFFICIAL BILL OF QUANTITIES (BoQ) ## Trade Materials & Merchant Supply Links Direct trade merchant pricing for BRE 365 attenuation crates, 150g/m² non-woven geotextile wrap, and 110mm silt traps. Awin Publisher ID: 3035391 Essential Structural CoreScrewfix / Toolstation ### Polystorm-R / AquaCell Modular Soakaway Crate 200L capacity (1000x500x400mm), 95% void ratio, 61 tonnes/m² vertical load rating Req: **8 units**£34.99 / crate [Order at Trade Counter (Screwfix)](https://www.awin1.com/cread.php?awinmid=1294&awinaffid=3035391&clickref=boq-0-soakaway-hub&ued=https%3A%2F%2Fwww.screwfix.com%2Fc%2Fbuilding-joinery%2Fdrainage%2Fcat840480) Mandatory Part H3 WrapTravis Perkins ### 150g/m² Non-Woven Geotextile Membrane Roll Needle-punched polypropylene filter fabric, prevents fines & silt migration into crate voids Req: **25m² roll (2.25m x 25m)**£42.00 / roll [Order at Trade Counter (Travis Perkins)](https://www.awin1.com/cread.php?awinmid=2024&awinaffid=3035391&clickref=boq-1-soakaway-hub&ued=https%3A%2F%2Fwww.travisperkins.co.uk%2Fgeotextiles%2Fc%2F1500096%2F) Part H3 Maintenance SumpToolstation ### 110mm Inline Silt Trap / Leaf Interceptor Chamber BS EN 1401-1 compliant, removable sediment basket required by BRE Digest 365 Req: **1–2 units**£58.50 [Order at Trade Counter (Toolstation)](https://www.awin1.com/cread.php?awinmid=16582&awinaffid=3035391&clickref=boq-2-soakaway-hub&ued=https%3A%2F%2Fwww.toolstation.com%2Funderground-drainage%2Fc608) Base Bedding & SurroundTravis Perkins ### 20–40mm Clean Washed Shingle / Pea Gravel (Bulk Bag) BS EN 12620 washed granular sub-base (100mm blinding bed & pipe surround) Req: **1–2 bulk bags (850kg each)**£65.00 / bulk bag [Order at Trade Counter (Travis Perkins)](https://www.awin1.com/cread.php?awinmid=2024&awinaffid=3035391&clickref=boq-3-soakaway-hub&ued=https%3A%2F%2Fwww.travisperkins.co.uk%2Faggregates%2Fc%2F1500057%2F) ## Related UK Statutory, Planning & Building Regulations Calculators (Verified Edge Mesh) - **[RSJCalculator.co.uk](https://rsjcalculator.co.uk)** — Eurocode 3 (BS EN 1993) structural steel beam & Building Regs Part A padstone bearing sizer - **[BuildOverAgreement.co.uk](https://buildoveragreement.co.uk)** — Building Regs Part H4 sewer standoff & all 10 UK Water Authority build-over fee calculator - **[PartyWallChecker.co.uk](https://partywallchecker.co.uk)** — Party Wall etc. Act 1996 s.1/s.2/s.6 notice generator & 3m/6m foundation depth checker - **[SoakawayCalculator.co.uk](https://soakawaycalculator.co.uk)** — BRE Digest 365 stormwater crate volume & Building Regs Part H3 percolation calculator - **[DroppedKerbCalculator.co.uk](https://droppedkerbcalculator.co.uk)** — Highways Act 1980 s.184 vehicle crossing council fees & 4.8m driveway depth checker - **[GardenOfficePower.co.uk](https://gardenofficepower.co.uk)** — BS 7671 18th Edition 3-core SWA armoured cable voltage drop vs LiFePO4 solar calculator - **[HedgeHeight.co.uk](https://hedgeheight.co.uk)** — Part 8 Anti-Social Behaviour Act 2003 & BRE Digest 470 Action Hedge Height (AHH) calculator - **[CouncilCredit.co.uk](https://councilcredit.co.uk)** — Local Government Finance Act 1992 CTB1 closed-account Council Tax credit recovery & band audit --- ## AI Ingestion & Edge Optimization Provenance (AnswerRail Verified) - **Edge Delivery & Markdown Compilation:** [AnswerRail.com](https://answerrail.com) — Layer-7 AI Crawler Content Negotiation, `/llms.txt` & Byte-0 Schema Compiler - **Dedicated AI Markdown Subdomain:** https://ai.soakawaycalculator.co.uk/ - **Cryptographic Ingestion Certificate:** https://answerrail.com/verify/soakawaycalculator.co.uk - **Live Crawler & Referral Telemetry:** https://answerrail.com/stats/soakawaycalculator.co.uk