Southern Water · overflow SWS00664
No active event
Recorded by the operator as PORTSMOUTH HARBOUR.
The monitor for overflow SWS00664 (operator listed as Southern Water) reports no current spill. The data records 15 spill events totalling 30 min in the last 30 days.
📍 50.78816°, -1.10593°
24
spill events
1h
cumulative discharge
12 min
longest single event
2026-05-14
first event on record
In the last 30 days this overflow recorded 1h of discharge. Across Southern Water's 1,046 monitored overflows the median was 0h. This site is in the top 9% by 30-day spill duration.
28 other overflows discharge into the Portsmouth Harbour. Combined recorded discharge in the last 30 days: 10h.
6 mm rain in the 24 h before, gauge Eastney, 4.2 km
6 mm rain in the 24 h before, gauge Eastney, 4.2 km
5.99 mm rain in the 24 h before, gauge Eastney, 4.2 km
5.99 mm rain in the 24 h before, gauge Eastney, 4.2 km
5.49 mm rain in the 24 h before, gauge Eastney, 4.2 km
5.49 mm rain in the 24 h before, gauge Eastney, 4.2 km
5.49 mm rain in the 24 h before, gauge Eastney, 4.2 km
5.76 mm rain in the 24 h before, gauge Eastney, 4.2 km
5.76 mm rain in the 24 h before, gauge Eastney, 4.2 km
5.76 mm rain in the 24 h before, gauge Eastney, 4.2 km
5.76 mm rain in the 24 h before, gauge Eastney, 4.2 km
5.76 mm rain in the 24 h before, gauge Eastney, 4.2 km
0 mm rain in the 24 h before, gauge Eastney, 4.2 km
0 mm rain in the 24 h before, gauge Eastney, 4.2 km
0 mm rain in the 24 h before, gauge Eastney, 4.2 km
Rainfall comes from the nearest Environment Agency rain gauge within 10 km, using 15-minute readings rolled into hourly totals. Where a gauge is further away, or too many readings are missing, we say so rather than guess. Rain figures do not show whether a discharge was permitted; that is a matter for the regulator. How we keep the record.
What the water company itself reported to the Environment Agency’s annual returns for this overflow, year by year. Hours are the total reported discharge duration; monitor working is the share of the year the event monitor was operating (a figure of 0% may mean no usable monitoring data rather than no spills). These figures are the operator's own reporting, not our measurement, and our live record above begins on 6 May 2026.
| Year | Spills counted | Hours | Monitor working | Matched by |
|---|---|---|---|---|
| 2024 | 30 | 31h | 100% | hub id |
| 2025 | 43 | 59h | 50% | hub id |
2024, the operator's stated reason: "High spill threshold not met"
2025, the operator's stated reason: "Not asset maintenance - Hydraulic capacity"
Source: Environment Agency, Event Duration Monitoring storm overflow annual returns, all years. Matched to this overflow by hub id.
The nearest Environment Agency rain gauge, Eastney, is 4.2 km from this overflow. It recorded 0.0 mm in the last 48 hours.
| Day (UTC) | Rain |
|---|---|
| 18 Oct 2026 | 0.0 mm |
| 17 Oct 2026 | 0.0 mm |
| 16 Oct 2026 | 6.3 mm |
| 15 Oct 2026 | 0.0 mm |
| 14 Oct 2026 | 0.0 mm |
| 13 Oct 2026 | 0.8 mm |
| 12 Oct 2026 | 1.9 mm |
Rainfall comes from 15-minute Environment Agency readings rolled into hourly and daily totals; the 48-hour figure rests on 184 of 192 possible readings. The gauge is 4.2 km from this overflow, so it may not match the rain at the site itself, and the latest day may be incomplete. Rain figures do not show whether a discharge was permitted; that is a matter for the regulator. How we keep the record.
Latest readings at the Environment Agency gauge "North Fareham", on the Wallington River,River Wallington, which is 9.4 km from this overflow.
These are the Environment Agency's own gauge readings at the named station, shown for context. The station measures the river, not this overflow, and a reading does not show whether a discharge occurred or was permitted. Trend compares the latest reading with the one nearest 24 hours earlier; a change of 5% or less is shown as steady. How we keep the record.
SO-G0003514 · SALINE WATER - ESTUARINE SITES - NON BATHING/SHELLFISH
505 m away
No swimmer-relevant measurements available.
SO-G0006569 · SALINE WATER - NON DESIGNATED BATHING BEACHES
2.1 km away
No swimmer-relevant measurements available.
SO-G0017029 · SALINE WATER - DESIGNATED BATHING BEACHES
2.1 km away · last tested 10 days ago
SO-G0006563 · SALINE WATER - NON DESIGNATED BATHING BEACHES
2.3 km away · last tested 5 weeks ago
SO-G0003491 · SALINE WATER - DESIGNATED BATHING BEACHES
2.4 km away · last tested 10 days ago
SO-G0003508 · SALINE WATER - COASTAL SITES - NON BATHING/SHELLFISH
3.3 km away
No swimmer-relevant measurements available.
The record above is verifiable from public Environment Agency and water-company data. Three official accountability channels — pre-filled with the evidence on this page.
If you can see foam, sewage debris, dead fish, or smell something wrong — submit a citizen report. Confirmed reports are added to the Truth Engine and strengthen the public record on this overflow.
📷 Report what you saw →The official complaints route. Most companies require submission through their web form rather than email — open the form, then paste the pre-filled letter.
Subject: Storm overflow SWS00664 on the PORTSMOUTH HARBOUR: request for information Dear Southern Water, I am writing about storm overflow SWS00664 on the PORTSMOUTH HARBOUR. Environment Agency storm overflow monitoring data for overflow SWS00664 on the PORTSMOUTH HARBOUR (operator listed as Southern Water) records 15 spill events starting between 18 September 2026 and 18 October 2026; the 14 with a published end time total 30 min. The most recent recorded event started on 1 October 2026 at 04:53 UTC. As of 18 October 2026 at 15:47 UTC, the monitor does not report the overflow as spilling. Further details from the public record: - Location: 50.78816, -1.10593 - Sources: Environment Agency National Storm Overflow Hub and Water Quality Archive (Open Government Licence v3.0), cross-referenced via River Truth (https://rivertruth.co.uk/overflow/8340) These figures are taken from public monitoring data as published and may be revised by the publisher. They are not a finding that any permit condition has been breached. [Add your personal context here, for example how you use this stretch of water.] Please could you tell me: 1. Whether the monitoring record summarised above is accurate and complete 2. What caused the recorded spill events 3. What work, if any, is planned at this overflow, and on what timeline 4. What measures are in place to reduce spills from this overflow in future [Delete if not applicable: I have copied the Environment Agency, Ofwat and my MP into this correspondence.] Yours faithfully, [Your name] [Your address] [Your customer reference if you are a Southern Water customer]
This overflow sits in the Portsmouth South constituency — currently represented by Stephen Morgan (Labour). Click below to open WriteToThem with the letter copied to your clipboard — paste it into the message box.
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Subject: Constituent query: storm overflow SWS00664 on the PORTSMOUTH HARBOUR Dear [your MP, WriteToThem will fill this in], I am writing as your constituent about public storm overflow monitoring data for our area. Environment Agency storm overflow monitoring data for overflow SWS00664 on the PORTSMOUTH HARBOUR (operator listed as Southern Water) records 15 spill events starting between 18 September 2026 and 18 October 2026; the 14 with a published end time total 30 min. The most recent recorded event started on 1 October 2026 at 04:53 UTC. As of 18 October 2026 at 15:47 UTC, the monitor does not report the overflow as spilling. Further details from the public record: - Location: 50.78816, -1.10593 - Sources: Environment Agency National Storm Overflow Hub and Water Quality Archive (Open Government Licence v3.0), cross-referenced via River Truth (https://rivertruth.co.uk/overflow/8340) These figures are taken from public monitoring data as published and may be revised by the publisher. They are not a finding that any permit condition has been breached. [Add your personal context here, for example how you and your family use this stretch of water.] I would like to ask: 1. Whether you support strengthening the regulatory regime for storm overflows, and monitor coverage in particular 2. Whether you would raise the monitoring data for this overflow with the Secretary of State for Environment, Food and Rural Affairs, the Environment Agency or Ofwat Yours sincerely, [Your name] [Your address (WriteToThem requires a postal address to verify your constituency)]
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For active pollution incidents — dead fish, foam, sewage on the riverbank — the EA hotline operates 24/7 and triggers a recorded investigation.