Business Plan 2025–30
This is our largest and most ambitious plan yet, double the size of our current delivery plan.
Our plan
We submitted an ambitious business plan for 2025-30 to our regulator Ofwat in 2023, outlining our proposals to approximately double our annual investment in water and waste services for our customers.
Our plan was challenging and showed how we will improve the health and wellbeing of our communities, protect and improve the environment and help sustain the local economy.
We will work differently, using innovative technology and nature-based solutions to go further and faster to tackle the challenges of water scarcity, river water quality, pollutions and flooding, delivering a step change in our environmental performance.
We will build new assets and secure reliable high-quality water supplies for the future.
Our response to Ofwat’s Draft Determination on our business plan
Maintaining and improving
Our response has focused on areas customers have told us are a priority:
- A reliable supply of water.
- Healthy rivers and seas.
- Trusted and easy customer service.
Our response
In our response we:
- stress the need for a plan which has achievable targets and balanced incentives and penalties
- stress the need for financial controls which will give confidence to investors to support delivery of the plan
- seek Ofwat’s approval for our multi-tiered approach to provide support for our customers who will struggle to pay their bills
express our support to deliver more of the investment through third parties, with oversight from Ofwat - underline our ability to deliver our plan and assure it.
New investment
Following further investigations and guidance from regulators our response includes new investment which will deliver:
- more environmental improvements in a shorter timescale, such as tackling storm overflows. We had requested extra time to introduce nature-based options first and give them time to deliver, rather than building storage and concrete options. However, we have now shortened the programme to meet Environment Agency deadlines
- the new water resources we need to keep taps flowing, increase our resilience to drought and protect our sensitive environments, following an update to our long-term draft Water Resources Management Plan. This now includes the upgrade of another water treatment works, bringing the total to five
- increased investment in cyber security.
Read the business plan documents submitted to our regulator below:
Our DD Response Document
Guide to Southern Water's DD Response to Documents
Southern Water DD Guide to Documents
Annexes and Appendices
SRN-DDR-012: Risk Appendix
SRN-DDR-021: Sustainable Botex Technical Annex
SRN-DDR-026: Real Price Effect and Frontier Shift Methodology
SRN-DDR-051: Delivery Action Plan
SRN-DDR-052: Price Control Deliverables
SRN-DDR-053: Financial Resilience Plan
SRN-DDR-056: Past Performance
SRN-DDR-057: Ofwat's Quality and Ambition Assessment
Enhancement Cost Evidence Cases
SRN-DDR-011: KPMG Industry Risk Analysis
SRN-DDR-018: Economic Insight Frontier Shift Report
SNR-DDR-019: Economic Insight Issues with Ofwat's Approach with Base Cost Assessment
SRN-DDR-020: Economic Insight Customers Not Paying Twice Report
SRN-DDR-022: Business Rates Cost Evidence Case
SRN-DDR-024: Environment Agency Changes to Charge Proposal for Water Discharges
SRN-DDR-025: Energy Cost Evidence Case
SRN-DDR-027: Supply Resilience Enhancement Programme Cost Evidence Case
SRN-DDR-028: Appendix A
SRN-DDR-028: Appendix B
SRN-DDR-028: Appendix C
SRN-DDR-028: Water Resources - Supply Enhancement Cost Evidence Case
SRN-DDR-029: Water Resources - Demand Leakage Enhancement Cost Evidence Case
SRN-DDR-030: Water Resources - Demand Water Efficiency Enhancement Cost Evidence Case
SRN-DDR-031: Water Resources - Smart Metering Enhancement Cost Evidence Case
SRN-DDR-032: Water Resources - Strategic Resource Option Enhancement Cost Evidence Case
SRN-DDR-033: Raw Water Deterioration Enhancement Cost Evidence Case
SRN-DDR-034: Lead Enhancement Cost Evidence Case
SRN-DDR-035: Appendix A - Weir Wood Reservoir Auxiliary Spillway Optioneering Report
SRN-DDR-035: Reservoir Safety Enhancement Cost Evidence Case
SRN-DDR-036: Appendix A - WSW AMP 8 Costs Forsharing
SRN-DDR-036: WINEP Supporting Water Abstraction Enhancement Cost Evidence Case
SRN-DDR-037: Water Network Resilience and Disinfection Enhancement Cost Evidence Case
SRN-DDR-038: Network and Information Systems Enhancement Cost Evidence Case
SRN-DDR-039: Market Based Delivery
SRN-DDR-039: Market Based Delivery Appendices
SRN-DDR-040: Appendix A - Southern Water PR24 SEMD Summary Report v1.0
SRN-DDR-040: Appendix B - Southern Water PR24 SEMD Benchmarking Review v1.0
SRN-DDR-040: Security and Emergency Measure Direction Enhancement Cost Evidence Case
SRN-DDR-041: Climate Resilience Enhancement Cost Evidence Case
SRN-DDR-042: Industrial Emissions Directive Enhancement Cost Evidence Case
SRN-DDR-043: WINEP - Nutrients Phosphorus and Nitrogen Schemes Enhancement Cost Evidence Case
SRN-DDR-044: WINEP - Storm Overflows Enhancement Cost Evidence Case
SRN-DDR-045: WINEP - Monitoring Enhancement Cost Evidence Case
SRN-DDR-046: WINEP - Wastewater Investigations Enhancement Cost Evidence Case
SRN-DDR-047: WINEP - Bioresources Additional Cake Storage Enhancement Cost Evidence Case
SRN-DDR-048: Wastewater Treatment Growth Enhancement Cost Evidence Case
SRN-DDR-049: Resilience - Coastal Enhancement Cost Evidence Case
SRN-DDR-050: Resilience - Infiltration Enhancement Cost Evidence Case
SRN-DDR-054: Estimating the Cost of Equity for PR24
SRN-DDR-055: Economic Insight - Gearing and Capital Structures Report
SRN-DDR-058: Cost of Embedded Debt
SRN-DDR-059: Estimating the Cost of New Debt
Cost Adjustment Claims
SRN-DDR-013: Regional Wages - Cost Adjustment Claim
SRN-DDR-014: Water Treatment Economies of Scale - Cost Adjustment Claim
SRN-DDR-015: Coastal Population - Cost Adjustment Claim
SRN-DDR-016: Bioresources AAD - C ost Adjustment Claim
SRN-DDR-017: Wastewater Growth Network Reinforcement - Cost Adjustment Claim
Data Tables and Commentaries
PR24 Draft Determination Commentary 2024 v1.0 OUT TABLES
PR24 Draft Determination Commentary 2024 v1.0 SUP TABLES
PR24 Draft Determination Commentary 2024 v1.0 SUM TABLES
PR24 Draft Determination Commentary 2024 v1.0 PD TABLES
PR24 Draft Determination Commentary 2024 v1.0 ADD TABLES
PR24 Draft Determination Commentary 2024 v1.0 RR TABLES
PR24 Draft Determination Commentary 2024 v1.0 CW TABLES
PR24 Draft Determination Commentary 2024 v1.0 CWW TABLES
PR24 Draft Determination Commentary 2024 v1.0 RES TABLES
PR24 Draft Determination Commentary 2024 v1.0 BIO TABLES
PR24 Draft Determination Commentary 2024 v1.0 RET TABLES
PR24 Draft Determination Commentary 2024 v1.0 DS TABLES
SRN DD Business Plan Table Summary
SRN PR24 DD Submission Data Tables
SRN PR24 DD Submission Data Tables ADD 1-21
SRN PR24 DD Submission Data Tables ADD 24-25
Financial Model
PR24 DD Response Proforma
SRN PR24 Draft Determinations Representation Proforma
PR19 Reconciliation Models
PR24 DD ODI Peformance Model 2023-24 SRN
PR24 DD ODI Peformance Model 2024-25 Southern Waer aligned to EP24
SRN PR24 RCV Adjustments Feeder Model v2.0
SRN 2023-24 PR19IPD04 In-Period Adjustments Model
SRN Cost Sharing Total Costs Reconciliation v4.0
SRN Bioresources Revenue Reconciliation Model Dec 2020 v2.3
SRN Developer Services Reconciliation Model
SRN PR24 Revenue Adjustments Feeder Model v2.0
SRN Residential Retail Reconciliation Model Dec 2020 v2.0
SRN RFI Model Apr 2023 v1.0 2024.25 charges
SRN RPI CPIH Wedge True Up Model Dec 2020 v5.0
Latest Information on PR24 Business Plan - March 24 Explanatory Note
Calculation of PR24 Business Plan Costs
PR24 Business Plan Data Tables March 24 Update
SRN39 Addendum Wastewater Treatment
SRN40 Addendum Storm Overflows
Business Plan Commentary 1
Business Plan Commentary 2
Business Plan Commentary 3
Business Plan Commentary 4
Business Plan Commentary 5
SRN PR24 Financial Model March 24 Update
SRN Business Plan Document Map
SRN Full Business Plan 2025-30
SRN01 Executive Summary
SRN02 Long-term delivery strategy
SRN03 Customer acceptability
SRN04 Costs and outcomes approach
SRN05 Wholesale Water (costs and outcomes)
SRN06 Wholesale Wastewater (costs and outcomes)
SRN07 Customer - HH & NHH (costs and outcomes)
SRN08 Affordability
SRN09 Deliverability
SRN10 Risk and Return
SRN11 Data and Assurance
SRN12 Long-term delivery strategy (Technical Annex)
01 PR24 Business Plan Commentary 2023
02 PR24 Business Plan Commentary 2023
03 PR24 Business Plan Commentary 2023
04 PR24 Business Plan Commentary 2023
05 PR24 Business Plan Commentary 2023
06 PR24 Business Plan Commentary 2023
07 PR24 Business Plan Commentary 2023
08 PR24 Business Plan Commentary 2023
09 PR24 Business Plan Commentary 2023
10 PR24 Business Plan Commentary 2023
11 PR24 Business Plan Commentary 2023
12 PR24 Business Plan Commentary 2023
SRN PR24 BP October data tables
SRN Hampshire Water Transfer ACWG strategic regional water resources model
SRN Havant Thicket and Recycling strategic regional water resource model
SRN River Itchen ACWG Version strategic regional water resource model
SRN T2ST ACWG Version strategic regional water resource model
SRN West Country Sources North ACWG strategic regional water resource model
SRN West Country south Sources and Transfers ACWG Version strategic regional water resource model
SRN West Country south southern Transfers ACWG Version strategic regional water resource model
SRN Desalination ACWG strategic regional water resource model
PR19 Innovation Funding
PR19 ODI Performance Model 2024-25
PR24 2023-24 ODI Performance Model
SRN - PR24-RCV Adjustments Feeder Model
SRN 2022-23 In-period Adjustments Model
SRN Cost Sharing Total Costs
SRN Reconciliation Model Dec 2020
SRN Bioresources Revenue Reconciliation Model Dec 2020
SRN Cost Of New Debt Indexation Model Dec 2020
SRN Developer Services Reconciliation Model
SRN Gearing Outperformance Sharing Mechanism Mar 2023
SRN Land Sales Model Dec 2020
SRN PR24 Revenue Adjustments Feeder Model
SRN Residential Retail Reconciliation Model Dec
SRN RFI Model
SRN RPI CPIH Wedge True Up Model Dec 2020
SRN Water Trading Incentive Model Dec 2020
Tax Reconciliation Tool Dec 2020
SRN13 Reputation, Trust and Transparency
SRN14 Customer Insight
SRN15 Cost and Option Methodology
SRN16 Real Price Effects Frontier Shift
SRN17 Direct Procurement for Customers and Alternative Delivery
SRN18 Performance Commitment Methodologies
SRN19 Botex
SRN36 Bioresources Strategy
SRN38 Water Industry National Environment Programme
SRN46 Net Zero Carbon
SRN47 Resilience in the Round
SRN48 Operational Resilience
SRN54 Innovation
SRN55 Affordability Model Methodology
SRN56 Deliverability
SRN57 Risk
SRN58 Uncertainty Mechanisms
SRN59 Past Performance (PR19 Reconciliation Mechanisms)
SRN60 Financeability
SRN61 Cost of Equity
SRN62 Cost of Debt
SRN63 Executive Pay and Dividend Policies
SRN64 Cost of Capital
SRN25 Supply Resilience Enhancement Programme
SRN26 Water Resources - Supply
SRN27 Water Resources - Demand
SRN28 Water Resources - Smart metering
SRN29 Water resources Strategic Resource Options
SRN30 Raw Water Deterioration
SRN31 Lead
SRN32 Reservoir Safety
SRN33 WINEP - Supporting Water Abstraction
SRN34 Network and Information Systems
SRN35 Security and Emergency Measures Direction
SRN37 Industrial Emissions Directive
SRN39 WINEP - Enhancing Waste Treatment
SRN40 WINEP - Storm Overflows
SRN41 WINEP - Monitoring
SRN42 WINEP - Wider Environmental Enhancement
SRN43 WINEP - Bioresources Cake Storage
SRN44 Wastewater Growth
SRN45 First Time Sewerage
SRN49 Resilience - Power
SRN50 Resilience - Infiltration
SRN51 Resilience - Heat
SRN52 Resilience - Flooding
SRN53 Resilience - Coastal