Wessex Water sustainability score: 43/100
Making progress starts at 46. The highest score on SINK is 71.
Wessex Water Services Limited is the regulated water and sewerage company for much of South West England and is part of the YTL group. It was incorporated in 1989 and is headquartered in Bath.
More about Wessex Water
Its filed accounts for the year to 30 June 2026 report revenue of £802.8m and an average of 2,768 employees. It is regulated by Ofwat and the Environment Agency.
Founded 1989Head office Bath, United KingdomStaff ~2,768Revenue £802.8M (FY2025/26, year to 30 June 2026)Website ↗
Wessex Water reports operational and supply-chain emissions, including capital carbon. Its latest fall in emissions, from 105 to 96 ktCO2e, was attributed by the company to lower rainfall. Pollution incidents rose to 62 per 10,000 km of sewer in 2024, from 36 in 2023, against a target of 19.5, and storm overflow spills rose sharply in 2023. Ofwat confirmed an £11m enforcement package in December 2025, the company incurred a £23.5m underperformance payment for 2024–25, and in July 2024 the ASA banned a TV advert that omitted its 2-star Environment Agency rating.
Wessex Water scores 43/100 (Below expectations) on SINK's independent climate assessment, scored from public data only. Scores are free. Nobody can pay to change a score, speed it up or hide it. Last verified October 2026.
That places Wessex Water joint 336th of 1,023 companies scored, and 5th of 11 in Water & Sewerage.
What is Wessex Water doing well, and where does it fall short?
Strongest on Carbon Footprint: Operations and Carbon Footprint: Supply Chain (8/10, 6/10). Weakest on Water Impact and Controversies & Red Flags (2/10, 3/10).
Where Wessex Water lost points
For each question that lost points, the evidence our public rubric looks for that we didn't find.
What would raise this score
- Its effect on waterMonitor its water use and take measures to reduce it.
- Its record on controversiesDeal with the findings under question 10, in public.
- How clean its energy isShow at least half its energy is renewable, with a transition plan.
Every question that lost points
- Emissions from its own operations8/10No verified figures published with their method and a falling trend.
- Emissions from its supply chain6/10No full value-chain map or supplier engagement programme.
- Whether its emissions are falling5/10No evidence of a year-on-year fall in its total emissions.
- How clean its energy is4/10Less than half its energy shown to be renewable, or no transition plan.
- Its effect on nature5/10Its effect on nature isn't measured or independently verified.
- How it uses materials and handles waste4/10No measurable waste or recycling targets reported publicly.
- Its effect on water2/10No monitoring of water use, or no measures to reduce it.
- Its climate targets4/10Its targets aren't science-based or committed to the Science Based Targets initiative.
- How openly it reports6/10No annual impact report, or no pay linked to climate targets.
- Its record on controversies3/10Points deducted for controversies or its business model. The finding is under question 10.
A score changes when the evidence does. We use new published evidence at the next rescore. Anyone can send us new evidence, free. How to send it.
How is Wessex Water's SINK score calculated?
Same ten questions for every company. No private weighting.
SINK = (0.3 × Base + 0.7 × Performance) × ScaleWhat evidence is Wessex Water's score based on?
12 sources used in this assessment. All publicly available. Each row shows which of the ten questions it informed.
33% of them were published by Wessex Water itself; the rest come from independent sources.
8 of 12 sources are independent of the company.
“Carbon: Table 11A: Streamlined energy and carbon reporting, task force on climate-related financial disclosures report.”
“using the water industry's standardised Carbon Accounting Workbook since 2007.”
“Our landholding was valued at 14,348 BU.”
“Wessex Water said it had not met its targets for leakage or serious pollution incidents.”
“Ofwat has confirmed that Wessex Water will fund an £11m enforcement package after the company failed to operate, maintain and upgrade its wastewater network adequately”
If you believe a source has been misread or a newer version exists, submit a challenge.
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How does Wessex Water compare with other water & sewerage companies?
Where Wessex Water sits among water & sewerage peers.
Among the 11 major water & sewerage brands we've scored, Wessex Water sits 5th of 11.
Who scores higher in Water & Sewerage?
The 3 companies in the sector scoring nearest above Wessex Water.
Pennon group Scope 1 and 2 emissions, assured by Jacobs, fell about 4% in 2025/26, mainly because more renewable electricity was bought for the Bristol Water region, and South West Water's electricity is backed by renewable energy certificates.
See the breakdown →United Utilities' 2025/26 market-based Scope 1 and 2 emissions were 539,041 tCO2e, including 239,498 tCO2e added by a 2026 industry update to process-emission factors.
See the breakdown →Scottish Water's operational emissions, audited to ISO 14064-1, fell from 462,000 tCO2e in 2006/07 to 220,000 tCO2e in 2024/25, and have been roughly flat for three years.
See the breakdown →Which companies moved this week, and why.
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