01
About the Utility
Scottish Water is Scotland’s publicly owned water and wastewater utility. Created under the Water Industry (Scotland) Act 2002, it is a Crown body owned by Scottish Ministers and regulated economically by the Water Industry Commission for Scotland. It serves about 5.4 million people, 2.67 million households and more than 160,000 business premises across a geographically dispersed territory. The system includes urban networks, remote rural assets, reservoirs, treatment works and extensive catchment land. Scottish Water’s mandate covers drinking-water production and distribution, wastewater collection and treatment, environmental performance and long-term infrastructure resilience. Its public ownership model removes shareholder dividends but ties the pace and scale of investment closely to regulated charges and Scottish Government borrowing.
02
Water System
Scottish Water operates 227 water treatment works, more than 1,200 treated-water storage tanks and 30,626 miles of water pipes. The system supplied about 1.48 billion litres of water each day in the FY2024/25 scale disclosure. Scotland’s water-rich image masks increasing regional supply stress: the utility’s climate adaptation work indicates that drought-condition supply deficits could rise from 60 million to 240 million litres per day under climate projections. Leakage was 453 million litres per day in FY2025/26, slightly above the in-year target of 450 Ml/d and broadly level with the prior year. Priorities include sustained leakage reduction, stronger interconnection, reservoir and catchment resilience, and better demand intelligence through domestic smart-monitor pilots and business metering.
03
Wastewater System
The wastewater estate includes 34,299 miles of sewer pipes and 1,837 wastewater treatment works in the FY2024/25 disclosure. Scottish Water reported collecting approximately 3.5 billion litres of wastewater and rainwater each day; that combined collection measure is not the same as wastewater treated. Performance investment is focused on treatment compliance, overflow monitoring, pollution reduction and resilience to extreme rainfall. The utility installed 1,000 combined-sewer-overflow monitors in 2024 and planned progressively wider coverage. Seafield, Scotland’s largest wastewater treatment works, is a strategic asset with a further sludge-storage investment phase planned from 2026. Catchment restoration and heat recovery from wastewater complement conventional treatment investment.
04
Performance
The annual-report performance measure, down marginally from 99.93%.
Reported against an in-year target of 450 Ml/day.
Customer interruptions lasting more than six hours; 5,047 were reported a year earlier.
The most serious incident categories, compared with four in the prior year.
Annual average leakage
Reported actuals, FY2021/22–FY2025/26
Reported annual averages, rounded to the nearest 1 Ml/day. The FY2025/26 actual was 453 Ml/day against an in-year target of 450 Ml/day.
Sources: Water Industry Commission for Scotland performance reporting and Scottish Water annual reporting.05
Investment & Priorities
Scottish Water reported £1.13 billion invested in capital and repairs in FY2025/26. Within the financial statements, regulated-company capital additions were £812 million; that accounting measure is shown separately and is not silently relabelled as total capital expenditure. The utility’s next regulatory cycle is centred on SR27, for 2027–2033. Its business plan proposes £13.4 billion of total investment and operating and essential costs, while the Delivery Vehicle 4 enterprise framework has a stated £5–9 billion delivery envelope. These are proposed or framework-scale future values, not actual annual investment. Current priorities include asset renewal, drought and flood resilience, wastewater compliance, digital monitoring, net-zero delivery and supply-chain capacity.
06
Sustainability & Resilience
Scottish Water’s sustainability programme combines operational carbon reduction, renewable-energy deployment and catchment restoration. Its FY2024/25 reporting recorded an operational greenhouse-gas footprint of 220,434 tonnes of carbon-dioxide equivalent and 10,892 tonnes of emissions reduction delivered during the year. Sixteen completed renewable schemes generated 6.42 gigawatt-hours. The longer-term strategy targets net-zero Scope 1 and Scope 2 emissions by 2040 and aims to move beyond net zero through land management and nature-based solutions. More than 800 hectares of peatland were restored between 2021 and 2025, including the completed Afton and Backwater reservoir projects, while the Loch Katrine plan proposes more than 4,600 hectares of native woodland.
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Key Challenges
- Closing emerging drought-condition supply deficits while keeping household demand affordable.
- Renewing a geographically dispersed asset base and sustaining leakage reductions.
- Reducing sewer overflows, pollution and climate-driven flooding across ageing networks.
- Scaling delivery capability for SR27 without weakening value-for-money or service performance.
- Reconciling a large construction programme with operational net-zero and nature-restoration ambitions.
08
Major Projects
Delivery Vehicle 4
An enterprise-style delivery model for major water and wastewater infrastructure, using long-term designers and asset-delivery partners.
- Status / period
- Preferred bidders confirmed; delivery period 2027–2033
- Investment / capacity
- £5–9bn framework value
Seafield sludge investment
Improves sludge storage and resilience at Scotland’s largest wastewater treatment works while reducing local odour impacts.
- Status / period
- Construction expected from summer 2026, subject to final approvals; completion targeted by end-2027
Loch Katrine landscape restoration
Combines catchment protection, peatland restoration and native woodland creation around a strategic source-water landscape.
- Status / period
- Ten-year land-management plan approved in 2024
- Investment / capacity
- 4,600+ hectares of proposed native woodland
Afton Reservoir peatland restoration
Restores peatland to protect source-water quality and retain carbon in an important Ayrshire catchment.
- Status / period
- Completed in 2025
- Investment / capacity
- More than 500 hectares restored