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Compliance Report Defra NSTS S1–S7

National Standards S1–S7 Compliance Report

Defra Non-Statutory Technical Standards: full S1 to S7 compliance audit and report.

Project Information

Define your development and contact details

Project Information

Project Name

Site Reference

Engineer Name

Date

Development Name

Name or reference of the development

Address

Postcode

Planning Reference Number

Applicant Name

Applicant Contact

Drainage Consultant Name

Company

Consultant Qualifications

Local Planning Authority

Lead Local Flood Authority

Water Company

Date of Assessment

Standard S1: Drainage Destination Hierarchy

Demonstrate compliance with the drainage hierarchy

Hierarchy: Infiltration → Watercourse → Surface Water Sewer → Combined Sewer

H1: Infiltration to Ground

BRE 365 Test Results

Feasibility Assessment

H2: Discharge to Watercourse

Watercourse Availability

Environmental Consent Required?

Status/Evidence

H3: Discharge to Surface Water Sewer

Sewer Network Availability

Capacity Confirmation from Water Company

H4: Discharge to Combined Sewer

Justification for Use (if applicable)

Overall S1 Assessment:

Standard S2: Interception & Storage

Demonstrate required interception volume is provided

Required Interception Volume (CIRIA C753)

0 m³

Typically 5-10mm rainfall over impermeable area

Site Impermeable Area (m²)

Interception Depth (mm)

CIRIA default: 6mm

Provided Interception Volume (m³)

Sum of all interception storage from SuDS components (green roofs, permeable paving, detention, etc.)

Component Summary (Link to S2 Interception Checker)

Component Type	Quantity	Unit	Storage Provided (m³)

Deemed Compliance:

Link to component calculators to demonstrate individual SuDS elements meet CIRIA standards. Reference calculations from Water Quality Calculator, Attenuation Calculator, etc.

S2 Assessment

Standard S3: Peak Flow Control

Demonstrate post-development discharge ≤ greenfield rates

S3 Requirement: Post-development peak discharge must not exceed greenfield runoff rate for design rainfall events (1yr, 30yr, 100yr), accounting for climate change.

Greenfield Runoff Rates (from Greenfield Calculator)

Greenfield QBAR (m³/s)

1yr Event (m³/s)

100yr Event (m³/s)

Post-Development Discharge (from Attenuation Calculator)

Designed Discharge QBAR (m³/s)

1yr Event (m³/s)

100yr Event (m³/s)

Climate Change Allowance Applied (%)

E.g. 40% uplift on rainfall for 100yr event

Urban Creep Allowance (%)

E.g. 10% increase in impermeable area

Attenuation Storage Provided

Total Storage Volume (m³)

Half-Drain Time (hours)

Should be ≤ 24 hours for flood performance

S3 Assessment

Standard S4: Water Quality

Demonstrate adequate treatment of runoff pollutants

S4 Requirement: Ensure suitable treatment of runoff through treatment train appropriate to receiving water sensitivity.

Receiving Water Sensitivity

Determines required level of treatment

CIRIA SIA (Source-Impact-Appraisal) Results

Reference output from Water Quality Calculator showing pollutant removal rates and treatment performance

Treatment Train Components

Screening: Filter drain, permeable pavement, swale - removes coarse sediment

Settling: Detention basin, pond, tank - removes suspended solids

Infiltration: Bioretention, soakaway - removes dissolved pollutants, infiltration option

Biodegradation: Wetland, swale, bioretention - microbial breakdown

Nutrient Uptake: Wetland, green roof, vegetation - nitrogen/phosphorus removal

Oil Separator Provided? (if required)

Required if parking area > 200 spaces or high-risk industrial use

Additional Comments

S4 Assessment

Standards S5-S7: Amenity, Biodiversity & Maintenance

Demonstrate integration, ecological benefit and long-term stewardship

S5: Amenity Value

Visual Integration: SuDS features designed as landscape amenity, not purely functional infrastructure

Multi-Functional Use: Ponds with recreational access, swales as green spaces, tree pits with seating areas

Public Access: SuDS features accessible and visible to residents/users where safe

Educational Signage: Interpretation boards explaining SuDS function and benefits

S5 Evidence

S6: Biodiversity Enhancement

Native Planting: SuDS landscapes use locally-native species, no invasive species

Habitat Creation: Wetland areas, riparian margins, tree establishment for wildlife

Biodiversity Net Gain: Demonstrates measurable improvement (if required by law)

Ecological Connectivity: Green corridors linking habitats across site

S6 Evidence

S7: Maintenance & Management

Maintenance Management Plan (MMP): Provided and signed-off by adoption body or management co

Adoption Pathway: Adoption agreement signed or management company established

Commuted Sum Agreed: (if adoptable) Financial provision for 30+ year maintenance

Adoption Body

MMP Document Reference

Commuted Sum (if applicable)

S7 Evidence

Report & Export

Generate comprehensive compliance report for planning submission

Compliance Summary

Hierarchy

Interception

Peak Flow

Quality

Amenity

Biodiversity

Maintenance

Report Contents

Cover page with project details and certification
Executive summary with overall compliance status
S1-S7 detailed assessments with evidence
Cross-references to supporting calculations
Appendix list and attachment checklist
Designer certification block
LLFA reviewer section for authority use

Additional Comments for Report

Engineer's Notes Optional, included in PDF report

Generate a comprehensive PDF compliance report ready for planning submission

S1-S7 Compliance Report

Defra 2025 National Standards for Sustainable Drainage

Project Overview

Development:	-
Address:	-
Planning Reference:	-
Drainage Consultant:	-
Consultant Company:	-

Executive Summary

Compliance Assessment Summary

Standard	Requirement	Status
S1	Drainage Destination Hierarchy	-
S2	Interception & Storage	-
S3	Peak Flow Control	-
S4	Water Quality	-
S5	Amenity Value	-
S6	Biodiversity Enhancement	-
S7	Maintenance & Adoption	-

Designer Certification

I certify that the above assessment represents a true and accurate evaluation of the development's compliance with Defra 2025 National Standards for Sustainable Drainage. All calculations and evidence have been prepared in accordance with CIRIA C753 guidance and relevant standards.

Consultant: _________________________	Date: _________________________
Company: _________________________	Qualifications: _________________________

For LLFA/LPA Use

Authority contact: _________________________ Date received: _____________
Authority review: PASS / FAIL / CONDITIONAL
Comments: ___________________________________________________________________