Regulatory Landscape

Schedule 3 of the Flood and Water Management Act 2010

The Flood and Water Management Act 2010 received Royal Assent on 8 April 2010. Schedule 3, titled "Designation of SuDS Approval Bodies and Consultation with Them," was included in the Act but was never formally commenced (brought into force). Instead, the government pursued a voluntary SuDS adoption standard whilst gathering evidence about implementation.

After sustained industry campaigning highlighting the benefits of Schedule 3, particularly in reducing flood risk and improving water quality, the government announced in January 2023 its intention to implement Schedule 3 in England. In preparation, the Department for Environment, Food & Rural Affairs (Defra) published the 2025 National Standards for Sustainable Drainage on 30 July 2025, setting out the technical criteria that Schedule 3 enforcement will require.

Schedule 3 proposes the creation of SuDS Approval Bodies (SABs), typically the county council or unitary authority (the same body that serves as the Lead Local Flood Authority, LLFA). The SAB would be responsible for: reviewing drainage designs for new development, approving schemes that meet the standards, adopting compliant SuDS infrastructure (taking ownership), and maintaining SuDS long-term. This creates a clear route for ensuring that SuDS are designed correctly, built to specification, and cared for over the decades of operation.

Current Status (Early 2026): Schedule 3 has not yet been formally commenced in England. However, the 2025 National Standards are already being actively referenced by planning authorities, Lead Local Flood Authorities, and sewerage undertakers when assessing drainage strategies. They have become the de facto technical benchmark, even before Schedule 3 commencement. In its June 2025 announcement accompanying the new National Standards, the Government indicated it favours improving the planning-policy approach to SuDS rather than commencing Schedule 3, with a further consultation on requiring standardised SuDS expected. Commencement therefore remains possible but is not confirmed.

Current Planning Policy Position

Even without Schedule 3 commencement, SuDS is already embedded in national planning policy and is a material consideration in planning decisions.

National Planning Policy Framework (NPPF): Paragraph 182 requires that major developments (generally 10 or more dwellings or 1,000 m² of commercial floor space) must be designed to incorporate sustainable drainage systems at a rate equivalent to the greenfield runoff rate for the same rainfall event. This is a binding policy requirement, not a guideline.

Technical Reference: Planning authorities and LLFAs use the 2025 National Standards (S1–S7) as the technical specification for what "incorporating SuDS" means. The standards provide quantified thresholds for water quantity, quality, amenity, and biodiversity, allowing objective assessment of drainage strategies.

Statutory Consultation: The LLFA is a statutory consultee on all major development planning applications in relation to flood risk and drainage. The LLFA will assess whether the proposed drainage strategy meets the 2025 National Standards. If it does not, the LLFA can recommend refusal of the application or require redesign.

Key Stakeholders and Their Roles

• Local Planning Authority (LPA): Determines planning applications. Uses NPPF paragraph 182 and the 2025 National Standards to assess drainage strategy adequacy. May refuse applications with inadequate drainage provision.
• Lead Local Flood Authority (LLFA): The statutory consultee on flood risk and drainage. Reviews flood risk assessments and drainage strategies. Provides expert advice to the LPA. Can recommend refusal if standards are not met. Once Schedule 3 is commenced, the LLFA will also be the SuDS Approval Body (SAB).
• Environment Agency: Provides strategic flood risk guidance. Reviews flood risk assessments for major applications, particularly those affecting main rivers or estuaries. Issues permits for direct discharge to main rivers.
• Sewerage Undertaker (Water Company): Operates and maintains the public sewer system. Has a statutory right to refuse connection if the sewer cannot accommodate the foul or surface water discharge. Often negotiates S106 contributions for sewer upgrades. Reviews drainage strategies to understand future maintenance burdens.
• SuDS Approval Body (SAB), Future Role: Once Schedule 3 commences, the SAB (typically the LLFA) will formally approve drainage designs before construction begins and will adopt and maintain SuDS long-term. This provides the missing link in current practice: long-term stewardship of SuDS.

What Triggers SuDS Requirements

SuDS requirements apply to new development in England, both on greenfield (previously undeveloped) and brownfield (previously developed) sites. The 2025 National Standards are designed primarily for schemes where a development is added to or built on previously undeveloped land.

• Major Development: 10 or more dwellings, or 1,000 m² of floor space, or 0.5 hectares or more. These must comply with NPPF paragraph 182 and, in practice, the 2025 National Standards.
• Minor Development: Smaller schemes (1–9 dwellings or less than 1,000 m²) are still expected to incorporate SuDS where practicable, following national planning guidance.
• Site Areas: Standards apply to the runoff generated from the developed site footprint: buildings, roads, car parks, paved areas. Landscaping, green infrastructure, and permeable areas are typically excluded from the "developed" area for runoff calculations.
• Greenfield Baseline: For any site, the "greenfield runoff rate" is calculated using IH124 QBAR methodology as if the entire site were left as undeveloped land. The SuDS scheme must ensure peak discharge for rainfall events does not exceed this baseline, protecting downstream areas from additional flood risk.
• Not Designed for Retrofit: The 2025 National Standards are written for new development. Retrofitting SuDS to existing urban areas is valuable but is addressed through separate guidance on existing developments and regeneration schemes. The standards can serve as a technical reference, but retrofit projects typically have different constraints (land availability, existing infrastructure, property ownership).

Devolved Administrations: Where the Position Differs

SuDS regulation is a devolved matter. The position above describes England. The other UK nations have already moved further, in some cases by a decade or more, and a UK-wide engineer or developer must understand which framework applies to a given site.

• Wales: Schedule 3 already in force. Wales commenced Schedule 3 of the Flood and Water Management Act 2010 on 7 January 2019. All construction work affecting drainage on developments of 100 m² or more requires SuDS Approval Body (SAB) approval before construction starts. Welsh SABs are typically the lead local authority. SuDS must comply with the Statutory National Standards for Sustainable Drainage Systems (Welsh Government, 2018). Adoption is by the SAB. Welsh Government has published several years of monitoring data showing the regime working at scale.
• Scotland: SuDS via Section 7 of the Sewerage (Scotland) Act 1968 + the CAR regime. Scotland was the UK pioneer of mandatory SuDS. Under Sewerage (Scotland) Act 1968 Section 7, Scottish Water has long required SuDS for any drainage to the public sewer. The Controlled Activities Regulations (CAR) 2011 additionally require a SEPA authorisation for any discharge to the water environment. Sewers for Scotland (4th Ed) sets the technical standard. Adoption is split: Scottish Water adopts the network where the source is the public sewer; SEPA permits cover discharges to watercourses. There is no separate SAB.
• Northern Ireland: DfI Rivers + Sewers for Adoption (NI). NI has no Schedule 3 equivalent. SuDS sits across Department for Infrastructure (DfI Rivers) for flood risk and watercourse discharge consents and NI Water for sewer connection consents. Adoption follows Sewers for Adoption (NI) for piped infrastructure; surface SuDS components are typically privately owned and maintained via management companies or section-76 agreements with NI Water. SuDS uptake is rising but remains less consistent than in Wales or Scotland.
• Cross-border note. A site straddling the border (very rare in practice but it happens at the Welsh and Scottish boundaries) is governed by the framework that applies to the part of the site where the drainage discharge originates. When in doubt, take pre-application advice from both LPAs / LLFAs / SABs.

LLFA vs SAB vs Sewerage Undertaker: Who Approves What

The single most-asked question by junior engineers and developers: who do I actually need to deal with? The answer depends on (a) which UK nation, (b) whether Schedule 3 is in force, and (c) where the runoff discharges. Use this decision tree:

• Step 1: Which nation? Wales: SAB is mandatory. Scotland: Scottish Water + SEPA. NI: DfI Rivers + NI Water. England: LLFA + sewerage undertaker (and SAB once Schedule 3 commences).
• Step 2: What is the discharge destination? The Defra NSTS Standard 1 hierarchy is binding: (1) infiltration to ground > (2) discharge to a watercourse > (3) discharge to a surface water sewer > (4) discharge to a combined sewer. You must justify why each higher option is not feasible before stepping down. Wrong destination = scheme rejection.
• Step 3: Identify the consent-giver for that destination.
  • Infiltration to ground (England): no formal consent for shallow infiltration outside groundwater Source Protection Zones; check Environment Agency groundwater protection position statement. Within an SPZ, EA pre-application advice required.
  • Watercourse discharge (England): Environment Agency consent under Land Drainage Act 1991 if discharging to a main river; LLFA / Internal Drainage Board consent if to an ordinary watercourse.
  • Surface water sewer: sewerage undertaker (Anglian, Severn Trent, Thames, Yorkshire, etc.). Apply under section 106 of the Water Industry Act 1991. Check capacity first.
  • Combined sewer: sewerage undertaker, but expect a refusal or significant attenuation requirement; combined sewer overflows are increasingly off-limits for new development.
• Step 4: Confirm planning consultation routes. The LLFA is the statutory consultee on flood risk and surface water drainage for major applications under the Town and Country Planning (Development Management Procedure) Order 2015. The LPA cannot grant permission without considering the LLFA's response. Once Schedule 3 is commenced in England, the SAB will become the formal approval body for the SuDS design itself, separate from the planning permission.
• Step 5: Confirm adoption route. Today in England, SuDS adoption is fragmented: piped infrastructure may be adopted by the sewerage undertaker under section 104 Water Industry Act 1991 and Water UK SSG/DCG; surface SuDS components (basins, swales, ponds) are typically privately owned and maintained through a management company, S106 agreement, or commuted-sum payment to the LPA. Once Schedule 3 commences, the SAB will adopt and maintain compliant SuDS, closing the long-standing stewardship gap.

One-line summary: Wales = SAB drives everything. Scotland = Scottish Water + SEPA. NI = DfI Rivers + NI Water. England (today) = LLFA advises planning + sewerage undertaker handles connections + private adoption for the surface SuDS. England (post-Schedule-3) = SAB approves and adopts.

Active Changes Worth Tracking

• Schedule 3 commencement (England): anticipated within 2–3 years of writing (early 2026). Defra has already published the 2025 National Standards in preparation. Track the Defra and DLUHC announcements.
• NPPF revisions: paragraph 167 (2021 ed) became paragraph 182 in the December 2024 update, which also extended SuDS expectations beyond major development to all applications affecting drainage. Future revisions are likely to strengthen this further; track the rolling NPPF consultation response.
• EA Climate Change Allowances: currently the May 2022 update (Table 3, surface water peak rainfall intensity). The EA has signalled a methodology refresh aligned to the UKCP18+ probabilistic projections; expect a new edition in the next 18–24 months.
• Building Regulations Approved Document H: under review for closer alignment with the SuDS hierarchy and energy-efficiency considerations for foul drainage.
• Water UK SSG/DCG: the current Sewerage Sector Guidance superseded the old Sewers for Adoption 8th Edition in April 2020. Expect periodic minor revisions; the substantive next edition is unlikely before 2027.