--- title: "All 10 UK Water Authorities Build Over Agreement Fees & Rules (2026) | Free Self-Cert vs Formal | BuildOverAgreement.co.uk" source_url: "https://buildoveragreement.co.uk/authorities" retrieved_by: "AnswerRail Edge Engine v1.1.0-parity-v20 (https://answerrail.com)" level_of_detail: "standard" token_payload_reduction: "92.4%" raw_html_bytes: 102185 compiled_body_bytes: 7734 entities_extracted: 4 currency_recall_static_html: "100%" monitored_currency_tokens: 40 link_recall_static_html: "100%" monitored_content_links: 10 rfc_compliance: "RFC 9110" last_verified_at: "2026-10-17T13:29:46.970Z" cache_age_seconds: 0 origin_cache_control: "public, max-age=0, must-revalidate" --- > **Canonical Source:** [https://buildoveragreement.co.uk/authorities](https://buildoveragreement.co.uk/authorities) > > *Compare 2026 Build Over Agreement fees (£0 Self-Cert vs £180–£385 Formal), max pipe diameters, turnaround times, and Part H4 rules across all 10 UK Water Authorities.* ### Organization: BuildOverAgreement.co.uk (UK Drainage & Environmental Standards Desk) | Field | Value | | :--- | :--- | | **Organization** | BuildOverAgreement.co.uk (UK Drainage & Environmental Standards Desk) | | **Official Website** | https://buildoveragreement.co.uk | | **Email** | compliance@buildoveragreement.co.uk | ### Entity: BuildOverAgreement.co.uk — UK Part H4 Sewer & Foundation Calculator | Property | Detail | | :--- | :--- | | **Type** | WebSite | | **Name** | BuildOverAgreement.co.uk — UK Part H4 Sewer & Foundation Calculator | ### Entity: BuildOverAgreement.co.uk Part H4 Compliance & Lintel CAD Calculator (2026) | Property | Detail | | :--- | :--- | | **Type** | WebApplication | | **Name** | BuildOverAgreement.co.uk Part H4 Compliance & Lintel CAD Calculator (2026) | ### Step-by-Step Procedure: How to Obtain a UK Build Over Agreement for an Extension (2026) > **Objective:** Step-by-step statutory process under Building Regulations Approved Document H4 and Section 174 Water Industry Act 1991. #### 1. Locate Public Sewer & Invert Depth Consult your CON29DW drainage search or lift the inspection chamber cover to measure sewer distance, pipe diameter (100mm–300mm), and invert depth. #### 2. Check 3.0m Trigger Zone & 45-Degree Load Cone Verify whether your new extension foundation trench falls within 3.0m horizontally of the sewer or inside the 45-degree angle of repose from the pipe invert. #### 3. Specify Foundation Depth & Bridging Lintel Excavate foundations to at least sewer invert + 150mm, and span over or near the pipe using reinforced concrete lintels with 450mm end bearings and a 150mm compressible crown void former. #### 4. Submit Free Self-Certification or Formal Dossier Lodge your 1:20 cross-section, 1:100 site plan, and WRc MSCC5 CCTV drain survey with your statutory water undertaker and Building Control before pouring concrete. UK Water Undertaker Directory # 10 UK Water Authorities Build Over Portal Guidelines & Fees Statutory fees, turnaround times, and self-certification eligibility limits for building within 3.0m of public sewers across England and Wales. Greater London, Thames Valley, Surrey, Berkshire, Oxfordshire, Gloucestershire, Wiltshire15d turnaround ## [Thames Water](/authorities/thames-water) Free self-cert online declaration available for standard pipes <\= 160mm diameter and < 3.0m deep where no manholes are enclosed. Class 1 (£343) for minor formal applications; Class 2 (£853) for complex or commercial assets. Self-Cert Fee:FREE (£0) Formal Class 1:£343.00 Max Self-Cert Dia:Ø150mm CCTV Requirement:Mandatory pre- and post-construction WRc-compliant CCTV survey on all formal agreements. [View Full Rules & Sizer](/authorities/thames-water) West Midlands, East Midlands, Warwickshire, Leicestershire, Nottinghamshire, Derbyshire, Staffordshire20d turnaround ## [Severn Trent Water](/authorities/severn-trent) Standard self-cert fee of £205 for straightforward domestic extensions. Formal agreements £545. Strict prohibition on building over manholes without physical external relocation. Self-Cert Fee:£205.00 Formal Class 1:£545.00 Max Self-Cert Dia:Ø150mm CCTV Requirement:Pre- and post-build CCTV drain survey required for all pipes over 150mm diameter or deeper than 1.5m. [View Full Rules & Sizer](/authorities/severn-trent) Greater Manchester, Merseyside, Lancashire, Cheshire, Cumbria15d turnaround ## [United Utilities](/authorities/united-utilities) Standard domestic self-cert consent £194. Formal build-over consent £478. Strict enforcement on clay pipes laid in glacial till and peat soils across the North West. Self-Cert Fee:£194.00 Formal Class 1:£478.00 Max Self-Cert Dia:Ø150mm CCTV Requirement:CCTV survey required to establish structural condition and exact location before any foundation excavation. [View Full Rules & Sizer](/authorities/united-utilities) Cambridgeshire, Norfolk, Suffolk, Essex, Lincolnshire, Northamptonshire, Bedfordshire20d turnaround ## [Anglian Water](/authorities/anglian-water) Minor approval £290. Major approval £690. Strict rules regarding high water table zones and fenland silts requiring engineered pile-and-beam bridging foundations. Self-Cert Fee:£290.00 Formal Class 1:£690.00 Max Self-Cert Dia:Ø150mm CCTV Requirement:Detailed condition survey required for all sewers traversing fenland or expansive clay strata. [View Full Rules & Sizer](/authorities/anglian-water) West Yorkshire, South Yorkshire, North Yorkshire, East Riding of Yorkshire15d turnaround ## [Yorkshire Water](/authorities/yorkshire-water) Standard £220 fee for qualified domestic schemes. £580 for formal agreements. Requires minimum 500mm clearance from strategic culverts and Victorian stone sewers common in Leeds and Sheffield. Self-Cert Fee:£220.00 Formal Class 1:£580.00 Max Self-Cert Dia:Ø150mm CCTV Requirement:Pre-construction CCTV survey report required with full defect scoring under WRc Sewer Inspection Manual. [View Full Rules & Sizer](/authorities/yorkshire-water) Hampshire, West Sussex, East Sussex, Kent, Isle of Wight25d turnaround ## [Southern Water](/authorities/southern-water) Self-cert applications £310. Formal technical agreements £780. Rigid enforcement in chalk aquifer protection zones and coastal clay formations. Self-Cert Fee:£310.00 Formal Class 1:£780.00 Max Self-Cert Dia:Ø150mm CCTV Requirement:Digital CCTV footage and defect log required before planning clearance or building control sign-off. [View Full Rules & Sizer](/authorities/southern-water) Bristol, Somerset, Dorset, Wiltshire, Bath and North East Somerset15d turnaround ## [Wessex Water](/authorities/wessex-water) Standard agreement fee £250. Complex / formal agreement £620. Special restrictions on steep gradient sewer lines in Avon and Mendip regions. Self-Cert Fee:£250.00 Formal Class 1:£620.00 Max Self-Cert Dia:Ø150mm CCTV Requirement:Condition survey mandatory to inspect for root ingress, displaced joints, and subsidence deformities. [View Full Rules & Sizer](/authorities/wessex-water) Tyne and Wear, County Durham, Northumberland, Tees Valley15d turnaround ## [Northumbrian Water](/authorities/northumbrian-water) Minor domestic approval £215. Major approval £530. Stringent foundation depth rules across post-industrial mining influence areas. Self-Cert Fee:£215.00 Formal Class 1:£530.00 Max Self-Cert Dia:Ø150mm CCTV Requirement:WRc coded survey required with visual footage and pipe gradient measurements. [View Full Rules & Sizer](/authorities/northumbrian-water) Cardiff, Swansea, Newport, Wrexham, Gwent, Glamorgan, Pembrokeshire20d turnaround ## [Dŵr Cymru Welsh Water](/authorities/welsh-water) Domestic standard build-over fee £230. Formal technical review £560. High emphasis on sustainable drainage (SuDS) alignment with Welsh statutory standards. Self-Cert Fee:£230.00 Formal Class 1:£560.00 Max Self-Cert Dia:Ø150mm CCTV Requirement:Certified CCTV survey required to confirm sewer status and determine if surface water or combined sewer. [View Full Rules & Sizer](/authorities/welsh-water) Devon, Cornwall, Isles of Scilly, Parts of Somerset and Dorset20d turnaround ## [South West Water](/authorities/south-west-water) Standard consent £240. Formal engineering agreement £595. Mandatory geotechnical assessment required where ground conditions involve granite boulders or steep gradients. Self-Cert Fee:£240.00 Formal Class 1:£595.00 Max Self-Cert Dia:Ø150mm CCTV Requirement:Detailed camera survey required prior to excavation near granite bedrock fissures or coastal sand beds. 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