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Permanent project revision

United Utilities' Storm-Overflow Monitors and Live Spill Map in Manchester

Revision 2026-10-16-baseline · effective 2026-10-16

Current revision. This is the snapshot used by the live entity page.

unreviewed

Created the first structured Evidence Passport with 22 claims and 8 source dossiers.

sha256:38c9c9b8059ac9a2603d7a22fd5e9390d772450a72c07053a5b999bd57e332a0
All revisions → Current entity page →

Change set

  • add /evidencePassport — Added claim-level evidence mapping and source dossiers.
  • add /revisionHistory — Established a permanent, hash-addressed baseline revision.
22
of 22 claims mapped
8
source dossiers
7
publication dates recorded
0
archives linked
0
exact locators
0
content captures hashed

Claims, one by one

The text below is copied verbatim from the published record. Each claim names the source dossiers that carry it; caveats stay attached to the claim they qualify.

Claim 1 clm-71a34d7df22999bf descriptive
United Utilities, the stock-market-listed company that runs water and sewerage across North West England
Published field
snippet · verbatim
Mapping
mapped · no interpretation or interpolation added by this file
What the mapping says
The company reports to the stock exchange as a listed PLC, and its chief executive describes the programme as the transformation of 'our region's water and wastewater infrastructure' in the North West.
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. United Utilities Group PLC — Preliminary full year results for the year ended 31 March 2026 (30 Apr 2026)
Claim 2 clm-b70d86284754032b descriptive
has an event duration monitor on every one of its storm overflows
Published field
snippet · verbatim
Mapping
mapped · no interpretation or interpolation added by this file
What the mapping says
The regulator's 2024 report lists 2,270 active storm overflows and 2,270 with event duration monitoring commissioned, 100%.
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. Environment Agency — United Utilities EPA data report 2024
Claim 3 clm-15445329ef5a0bd2 descriptive
including the relief points where central and north Manchester's combined sewers spill into the Rivers Irk and Medlock
Published field
snippet · verbatim
Mapping
mapped · no interpretation or interpolation added by this file
What the mapping says
The 2025 return lists monitored combined sewer overflows in central Manchester discharging to the River Medlock (Princess St/Whitworth St, Charles St/Princess St, Oxford Road/Grosvenor Street) and in north Manchester to the River Irk (Aspin Lane, Rochdale Road/Collyhurst); the company places Aspin Lane on the edge of the Green Quarter and NOMA.
Caveat
The location of each overflow is given in the return as a grid reference and site name, not by local authority.

Sources carrying this claim

  1. Environment Agency — Event Duration Monitoring: Storm Overflow Annual Return 2025 (dataset and documentation)
  2. United Utilities — United Utilities completes Manchester sewer improvement scheme (17 Aug 2026)
Claim 4 clm-6ac87b3d29bae913 descriptive
The monitors record how often and for how long each overflow discharges.
Published field
snippet · verbatim
Mapping
mapped · no interpretation or interpolation added by this file
What the mapping says
The dataset documentation defines two measured columns: hours each overflow discharged in 2025 and the number of spills counted with the 12-24 hour method.
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. Environment Agency — Event Duration Monitoring: Storm Overflow Annual Return 2025 (dataset and documentation)
Claim 5 clm-f28a6e5290449edb descriptive
Every year the company returns those figures to the Environment Agency, which publishes them overflow by overflow
Published field
snippet · verbatim
Mapping
mapped · no interpretation or interpolation added by this file
What the mapping says
The company says it provides verified annual discharge data to the regulator, which reviews and publishes it; the 2025 dataset has one row per storm overflow.
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. Environment Agency — Event Duration Monitoring: Storm Overflow Annual Return 2025 (dataset and documentation)
  2. United Utilities — Response to environmental information request EIR-738 (20 Mar 2026)
Claim 6 clm-60af3a159ce79f37 quantitative
since April 2024 it has also shown each overflow's status on an interactive near-real-time map
Published field
snippet · verbatim
Mapping
mapped · no interpretation or interpolation added by this file
What the mapping says
Utility Week reported on 30 April 2024 that United Utilities was among three companies that had launched such maps; the company describes its map as interactive, near real-time and covering all its storm overflows.
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. Utility Week — Three water companies launch live sewage discharge maps (30 Apr 2024)
  2. United Utilities Better Rivers — What is the storm overflow map?
Claim 7 clm-442e0f91bf06691f descriptive
companies aim to transmit a discharge within an hour
Published field
snippet · verbatim
Mapping
mapped · no interpretation or interpolation added by this file
What the mapping says
The company's information-request reply states the transmission aim and describes the route from monitor to cloud storage to map.
Caveat
This is an aim, not a measured delay.

Sources carrying this claim

  1. United Utilities — Response to environmental information request EIR-738 (20 Mar 2026)
Claim 8 clm-b017400ab404c402 quantitative
An overflow that spills more than 30 times in a year has to be given a reason in the return.
Published field
snippet · verbatim
Mapping
mapped · no interpretation or interpolation added by this file
What the mapping says
The documentation asks companies to state a single-year reason in the 'High Spill Frequency – Operational Review' column when the spill count exceeds the threshold of more than 30, which is based on spill frequency investigation triggers.
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. Environment Agency — Event Duration Monitoring: Storm Overflow Annual Return 2025 (dataset and documentation)
Claim 9 clm-48f6508092259b3f descriptive
The operator is a regional private utility
Published field
snippet · verbatim
Mapping
mapped · no interpretation or interpolation added by this file
What the mapping says
The listed company's results describe the water and wastewater infrastructure of its region, the North West, as its own business.
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. United Utilities Group PLC — Preliminary full year results for the year ended 31 March 2026 (30 Apr 2026)
Claim 10 clm-65d5835808d6273e quantitative
In 2025 the Aspin Lane overflow on the River Irk, on the edge of the Green Quarter and NOMA district, spilled 50 times for a total of 35 hours
Published field
impact · verbatim
Mapping
mapped · no interpretation or interpolation added by this file
What the mapping says
The 2025 return's row for Aspin Lane CSO (receiving water River Irk) gives 50 counted spills and a total duration of 35:04:00; the company's announcement places the site on the edge of Manchester's Green Quarter and NOMA district.
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. Environment Agency — Event Duration Monitoring: Storm Overflow Annual Return 2025 (dataset and documentation)
  2. United Utilities — United Utilities completes Manchester sewer improvement scheme (17 Aug 2026)
Claim 11 clm-15566676a4fbbbeb quantitative
(its long-term average is 53 spills a year); the return gives the reason as hydraulic capacity and marks an Environment Act improvement as ongoing
Published field
impact · verbatim
Mapping
mapped · no interpretation or interpolation added by this file
What the mapping says
The same row gives a long-term average spill count of 53, 'Not asset maintenance - Hydraulic capacity' as the high-spill reason, and 'Env Act (SODRP) improvement ongoing' for the reporting period.
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. Environment Agency — Event Duration Monitoring: Storm Overflow Annual Return 2025 (dataset and documentation)
Claim 12 clm-83238e8a9b61f026 quantitative
In 2026 United Utilities invested £1.3 million to disconnect surface water from the combined sewer there and sealed the overflow off.
Published field
impact · verbatim
Mapping
mapped · no interpretation or interpolation added by this file
What the mapping says
The company says it invested £1.3 million to disconnect surface water drainage from the combined sewer at Aspin Lane, removing enough surface water to prevent the storm overflow from operating, and that the overflow has been sealed off; the work began in June 2026.
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. United Utilities — United Utilities completes Manchester sewer improvement scheme (17 Aug 2026)
Claim 13 clm-999f739ea785dab2 quantitative
On the same river the Rochdale Road/Collyhurst overflow spilled 92 times, for 415 hours, with no improvement action in the reporting period.
Published field
impact · verbatim
Mapping
mapped · no interpretation or interpolation added by this file
What the mapping says
The return's row for Rochdale Rd / Burgin Walk CSO (operational name Rochdale Road/Collyhurst CSO, receiving water The River Irk) gives 92 counted spills, a duration of 415:26:00, reason 'Not asset maintenance - Hydraulic capacity', 'Env Act (SODRP) investigation ongoing' and 'No improvement action in reporting period'.
Caveat
An investigation at this overflow was recorded as ongoing.

Sources carrying this claim

  1. Environment Agency — Event Duration Monitoring: Storm Overflow Annual Return 2025 (dataset and documentation)
Claim 14 clm-401a48fe052b5433 quantitative
Across the North West the company reported a 22% reduction in spill numbers in 2025
Published field
impact · verbatim
Mapping
mapped · no interpretation or interpolation added by this file
What the mapping says
The company's announcement of 26 March 2026 says the Environment Agency's figures confirmed a 22% reduction in spill numbers, 16,974 fewer spills.
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. United Utilities — United Utilities cuts storm overflow spills across the North West (26 Mar 2026)
Claim 15 clm-de82bff0209e55ef quantitative
credits 129 interventions at 125 Greater Manchester overflows with preventing 4,225 activations; these are its own figures
Published field
impact · verbatim
Mapping
mapped · no interpretation or interpolation added by this file
What the mapping says
The announcement says that across Greater Manchester 129 interventions improved 125 storm overflows and together prevented 4,225 overflow activations.
Caveat
The company does not say how the prevented activations were calculated, and the figure covers all of Greater Manchester.

Sources carrying this claim

  1. United Utilities — United Utilities cuts storm overflow spills across the North West (26 Mar 2026)
Claim 16 clm-26d237a329a9ffb5 quantitative
the Environment Agency rated the company four stars for 2023 and two stars, 'requires improvement', for 2024
Published field
impact · verbatim
Mapping
mapped · no interpretation or interpolation added by this file
What the mapping says
The regulator's star-rating table gives 4 stars ('Industry leading company') for 2023 and 2 stars ('Company requires improvement') for 2024.
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. Environment Agency — United Utilities EPA data report 2024
Claim 17 clm-504fa7034734135a quantitative
its 347 sewerage pollution incidents were rated red
Published field
impact · verbatim
Mapping
mapped · no interpretation or interpolation added by this file
What the mapping says
The report rates the 2024 sewerage pollution incident metric red: 347 incidents, 45 per 10,000 km of sewer, where 158 or fewer would have been green.
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. Environment Agency — United Utilities EPA data report 2024
Claim 18 clm-42de86a96d678028 quantitative
an Ofwat enforcement case opened in 2024 was still unresolved at 31 March 2026, with a possible penalty the company puts at around £100 million
Published field
impact · verbatim
Mapping
mapped · no interpretation or interpolation added by this file
What the mapping says
The results statement says that at 31 March 2026 the water company remained subject to the enforcement case Ofwat opened in 2024, that a penalty could reach 10 per cent of relevant wastewater turnover, around £100 million, and that no provision has been recognised.
Caveat
Ofwat has not found a breach; the company says the opening of a case does not imply that a penalty will follow.

Sources carrying this claim

  1. United Utilities Group PLC — Preliminary full year results for the year ended 31 March 2026 (30 Apr 2026)
Claim 19 clm-182ed027687d03a2 quantitative
more than 30 spills in a year and the company has to explain itself to the regulator
Published field
lesson · verbatim
Mapping
mapped · no interpretation or interpolation added by this file
What the mapping says
The return requires a reason for any overflow above the single-year threshold of more than 30 spills.
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. Environment Agency — Event Duration Monitoring: Storm Overflow Annual Return 2025 (dataset and documentation)
Claim 20 clm-a5344da661cac9dd quantitative
In Manchester one overflow on the Irk was sealed off in 2026 after a year of 50 spills, as part of the company's wider programme
Published field
lesson · verbatim
Mapping
mapped · no interpretation or interpolation added by this file
What the mapping says
The 2025 return gives Aspin Lane 50 spills; the company's 2026 announcement says the overflow was sealed off and that the scheme is part of its wider programme.
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. Environment Agency — Event Duration Monitoring: Storm Overflow Annual Return 2025 (dataset and documentation)
  2. United Utilities — United Utilities completes Manchester sewer improvement scheme (17 Aug 2026)
Claim 21 clm-c52b647885dba0ae quantitative
while another on the same river logged 92 with no improvement action
Published field
lesson · verbatim
Mapping
mapped · no interpretation or interpolation added by this file
What the mapping says
The Rochdale Road/Collyhurst row gives 92 spills and 'No improvement action in reporting period'.
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. Environment Agency — Event Duration Monitoring: Storm Overflow Annual Return 2025 (dataset and documentation)
Claim 22 clm-3f6aae82657b262c quantitative
Ofwat's case, opened in 2024, was still open in 2026
Published field
lesson · verbatim
Mapping
mapped · no interpretation or interpolation added by this file
What the mapping says
The results statement of 30 April 2026 says the case remained open at 31 March 2026 with no firm timeframe for its conclusion.
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. United Utilities Group PLC — Preliminary full year results for the year ended 31 March 2026 (30 Apr 2026)

Source dossiers and revision state

This layer records what is known about each source, what is still missing, and the exact snapshot this page is rendering. A missing date, archive or hash stays visible as missing.

unreviewed Revision 2026-10-16-baseline effective 2026-10-16 · created 2026-10-16

Awaiting operator and domain-expert review; publication of this revision implies neither.

sha256:38c9c9b8059ac9a2603d7a22fd5e9390d772450a72c07053a5b999bd57e332a0
Revision history → Permanent version link → Machine-readable record → Evidence Constitution →
22
of 22 claims mapped
8
source dossiers
7
publication dates recorded
0
archives linked
0
exact locators
0
content captures hashed

Governance facts carried by the record

Operator
United Utilities Water Limited (regional private water and sewerage company for North West England); annual returns reviewed and published by the Environment Agency
Actor types
utility, national-government
Funding model
utility
Funding description
United Utilities; the Aspin Lane overflow removal cost £1.3 million and forms part of the company's 2025–30 investment programme. No budget for the monitoring itself located.
Cost
Not recorded
Ownership
Not recorded
Decision rights
Not recorded
Exit conditions
Not recorded

8 source dossiers

Environment Agency — Event Duration Monitoring: Storm Overflow Annual Return 2025 (dataset and documentation) environment.data.gov.uk · 10 linked claims

Open original source ↗

Stable source ID
src-cf77377d65bb73d5
Publisher
Name not classified · environment.data.gov.uk
Type / language
web-page · language not classified
Published
2026-03-26
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-10-16
Dossier created
2026-10-16
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

The regulator's dataset of every monitored storm overflow in England for 2025, with its documentation. United Utilities' sheet lists ASPIN LANE CSO 281CJ (River Irk): 50 counted spills, duration 35:04:00, long-term average 53, data from 2019, reason 'Not asset maintenance - Hydraulic capacity', 'Env Act (SODRP) improvement ongoing'; and the Rochdale Road/Collyhurst CSO (River Irk): 92 spills, 415:26:00, 'No improvement action in reporting period'. The documentation defines the counts and the single-year high spill frequency threshold of more than 30. The workbook notes it was updated in August 2026 after a re-submission by another company.

Descriptive only — not page/paragraph exact
Claims linked
Environment Agency — United Utilities EPA data report 2024 gov.uk · 3 linked claims

Open original source ↗

Stable source ID
src-45332543d2906e2d
Publisher
Name not classified · gov.uk
Type / language
web-page · language not classified
Published
2025-10-23
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-10-16
Dossier created
2026-10-16
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

The Environment Agency's annual assessment of the company: four stars ('Industry leading company') for 2023 and two stars ('Company requires improvement') for 2024; 347 sewerage pollution incidents in 2024, rated red, against 216 in 2023; 2,270 active storm overflows, all with event duration monitoring commissioned.

Descriptive only — not page/paragraph exact
Claims linked
United Utilities — United Utilities completes Manchester sewer improvement scheme (17 Aug 2026) corporate.unitedutilities.com · 4 linked claims

Open original source ↗

Stable source ID
src-519d30ab9a5d9102
Publisher
Name not classified · corporate.unitedutilities.com
Type / language
web-page · language not classified
Published
2026-08-17
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-10-16
Dossier created
2026-10-16
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

Company announcement: £1.3 million spent disconnecting surface water drainage from the combined sewer at Aspin Lane, on the edge of Manchester's Green Quarter and NOMA district; enough surface water removed to prevent the storm overflow from operating, and the overflow sealed off; work began in June and finished ahead of a 19-week schedule; part of the company's wider programme to improve rivers.

Descriptive only — not page/paragraph exact
Claims linked
United Utilities — United Utilities cuts storm overflow spills across the North West (26 Mar 2026) corporate.unitedutilities.com · 2 linked claims

Open original source ↗

Stable source ID
src-766162f954d9c0c0
Publisher
Name not classified · corporate.unitedutilities.com
Type / language
web-page · language not classified
Published
2026-03-26
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-10-16
Dossier created
2026-10-16
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

Company announcement on the day the Environment Agency released the 2025 figures: a 22% reduction in spill numbers (16,974 fewer) and 27% in duration across the North West; across Greater Manchester, 129 interventions at 125 storm overflows that the company says prevented 4,225 activations.

Descriptive only — not page/paragraph exact
Claims linked
United Utilities Group PLC — Preliminary full year results for the year ended 31 March 2026 (30 Apr 2026) unitedutilities.com · 4 linked claims

Open original source ↗

Stable source ID
src-c3911a1e0c0c2a6c
Publisher
Name not classified · unitedutilities.com
Type / language
pdf · language not classified
Published
2026-04-30
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-10-16
Dossier created
2026-10-16
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

Stock-exchange results statement. Under contingent liabilities: the water company remains subject to the enforcement case Ofwat opened in 2024; a penalty could reach 10 per cent of relevant wastewater turnover, around £100 million; no provision recognised; no firm timeframe for conclusion; a parallel Environment Agency investigation into permit compliance is ongoing.

Descriptive only — not page/paragraph exact
Claims linked
Utility Week — Three water companies launch live sewage discharge maps (30 Apr 2024) staging4.utilityweek.co.uk · 1 linked claim

Open original source ↗

Stable source ID
src-5c1f0e2b9e012068
Publisher
Name not classified · staging4.utilityweek.co.uk
Type / language
web-page · language not classified
Published
2024-04-30
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-10-16
Dossier created
2026-10-16
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

Trade-press report by Ruth Williams: Northumbrian, United Utilities and Yorkshire have launched interactive near-real time digital maps of storm overflows in their regions ahead of bathing water season, showing locations and ongoing operations.

Descriptive only — not page/paragraph exact
Claims linked
United Utilities — Response to environmental information request EIR-738 (20 Mar 2026) cumbria.unitedutilities.com · 2 linked claims

Open original source ↗

Stable source ID
src-f779ebd75e1bcf00
Publisher
Name not classified · cumbria.unitedutilities.com
Type / language
pdf · language not classified
Published
2026-03-20
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-10-16
Dossier created
2026-10-16
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

The company's reply to an information request (about an area of the Wirral). Explains the data flow: near-real-time data detected by event duration monitors goes to each company's cloud storage and on to the map and the national Stream hub; companies aim to transmit a discharge within an hour; raw telemetry is unvalidated.

Descriptive only — not page/paragraph exact
Claims linked
United Utilities Better Rivers — What is the storm overflow map? unitedutilities.com · 1 linked claim

Open original source ↗

Stable source ID
src-56f915b5c842f64f
Publisher
Name not classified · unitedutilities.com
Type / language
web-page · language not classified
Published
Not recorded
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-10-16
Dossier created
2026-10-16
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

The company's description of its map: interactive and near real-time, including all its storm overflows.

Descriptive only — not page/paragraph exact
Claims linked
Known limits of this file
  • Publisher names and source languages have not yet been classified; domains are recorded without guessing.
  • Existing source notes are descriptive locators, not page- or paragraph-exact citations.
  • A missing archive, publication date or content hash is shown as null rather than inferred.
  • The project-level evidence grade ranks the strongest source in the entry; it is not a truth score for every claim.