Northumbrian Water Limited supplies water and sewerage services in North East England and, as Essex & Suffolk Water, water in Essex and Suffolk.
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Northumbrian Water's net market-based operational emissions fell from 68.6 to 15.9 ktCO2e between 2019/20 and 2024/25, relying on renewable electricity and gas certificates, while gross location-based emissions moved from 163.3 to 152.6 kt. Natural gas use remains above its 2019/20 baseline. Its pollution incident rate was 39 per 10,000 km of sewer, rated red, and the Environment Agency rated it 2 stars for 2024. In June 2025 it agreed a £15.7m Ofwat enforcement package.
Northumbrian Water scores 42/100 (Below expectations) on SINK's independent climate assessment, scored from public data only. Fees pay for the review, never the result. Last verified October 2026.
That places Northumbrian Water joint 317th of 847 companies scored, and 6th of 11 in Water & Sewerage.
Where Northumbrian Water sits among water & sewerage peers.
Among the 11 major water & sewerage brands we've scored, Northumbrian Water sits 6th of 11.
Its three lowest-scoring questions, and what the evidence didn't show.
Pollution rate rose from 19.96 (2022/23) to 38.97 (2024/25).
Net operational emissions fell 68.6 to 15.9 ktCO2e (2019/20–2024/25) via renewable contracts and credits; gross location-based emissions moved only 163.3 to 152.6 ktCO2e.
No SBTi commitment found.
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Get in touch →Strongest on Transparency & Accountability and Carbon Footprint — Operations (8/10, 7/10). Weakest on Water Impact and Emissions Trajectory (2/10, 3/10).
The 3 companies in the sector scoring nearest above Northumbrian Water.
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 →Wessex Water reports operational and supply-chain emissions, including capital carbon.
See the breakdown →The formula and all 12 sources.
Same ten questions for every company. No private weighting.
SINK = (0.3 × Base + 0.7 × Performance) × Scale12 sources used in this assessment. All publicly available. Each row shows which of the ten questions it informed.
“reported process emissions significantly (from 27ktCO2e to 126kTCO2e despite no significant changes on the ground)”
“Our emissions have been externally assured in accordance with ISO 14064-1, to ensure validity and transparency.”
“Of these 609 ktCO2e, the five largest categories being Capital/ Construction (35%), wastewater process emissions (21%), purchased goods and services (16%)”
“We own approximately 2,160 ha of land that has the conservation designation of SSSI.”
“97.2% numeric discharge permit compliance”
“In August 2024, Ofwat indicated Northumbrian would pay a £17m penalty (5% of relevant turnover)”
“The Group is ultimately owned by a consortium of long-term infrastructure investors, including companies within the CK Hutchison group and KKR.”
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Northumbrian Water Limited supplies water and sewerage services in North East England and, as Essex & Suffolk Water, water in Essex and Suffolk. It is privately owned, was incorporated in 1989 and is headquartered in Durham. Its annual report for the year to 31 March 2026 reports revenue of £1,182.0m and an average of 3,844 employees. It is regulated by Ofwat and the Environment Agency.
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