Overflow Map
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Multiple overflows at one location
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Overflow Map FAQs
The map shows all Scottish Water monitored overflows for which we can publish data in near real-time. Some parts of the system are operated on our behalf by Private Finance Initiative (PFI) companies. Scottish Water does not publish this information.
The map does not show unmonitored overflows at this time.
Not all overflows are Combined Sewer Overflows (CSOs). The overflow map shows all Scottish Water monitored overflows for which we can publish data in near real-time, including:
- Combined Sewer Overflows (CSOs), which stop the system from becoming overwhelmed during heavy rainfall
- Settled Storm Sewage Overflows (SSSOs), a form of CSO that provides a level of treatment or settlement before discharge
- Emergency Overflows (EOs), which should only operate in the event of sewer system failure and should not operate in response to rainfall
There are more than 1,000 monitored overflows included on the map at this time.
As we continue our review/verification processes and monitor installation programme, we will look to publish data for further monitored overflows in future. The map does not show unmonitored overflows at this time.
'Near real-time' data means the information available in the last 48 hours which indicates overflow status and the duration of an overflow event during this time.
The map is updated every 60 minutes based on available information and the last time the map was updated is included top right above the map.
However, not all overflows record or send data at the same frequency so we have included the last date and time the data was updated in the information for each overflow location.
Previously, monitors were generally installed to meet licence requirements and for reporting on an annual basis. This means, how often data is recorded and received from these monitors can vary. The near real-time status and overflow events published on the map are based on the data available.
The map, and associated data, don't advise if it's safe to swim or enter the water. Overflows are just one of several sources that could impact the water quality and safety of waterbodies, and these can vary depending on the surrounding area.
For the latest information on bathing water quality visit: Bathing Waters | Home | Scottish Environment Protection Agency (SEPA)
The map will only indicate if a monitor has been activated and an overflow event may have occurred. Planned investment priority information is included.
Here are just some of the factors that could have an impact on water quality:
- Agricultural run-off from farmland
- Discharges from private systems such as septic tanks and overflows
- Road runoff from surrounding roads and highway drainage systems
- Waste pipes from houses wrongly connected to surface water sewers or culverts
- Domestic animal waste, such as dogs, farming livestock, wild animals, and birds
- Human behaviour, due to items wrongly disposed of down sinks and toilets
Further information is available at:
River basin management planning | Scottish Environment Protection Agency (SEPA)
If you would like to provide feedback on your experience using the map with suggestions for us to make further improvements please use the Feedback Form at the bottom of this page.
The map uses clustering to avoid being overwhelmed with information. To make it easier for users, the EDM monitor locations are clustered around a central point using a blue circular icon, with the number of monitor locations displayed.
To see individual locations, users should select the circle icon which will zoom in to show the separate colour-coded icons so you can choose which location to view.
A double water drop icon indicates there are multiple overflows at the same location. Once this icon is selected, the individual overflows will be displayed and you can choose the details you wish to view.
There are several reasons why an Event Duration Monitor (EDM) may be showing no data available.
- The EDM may be faulty or damaged and needs to be repaired. We will be aware of this and repairs will be underway as soon as possible
- The EDM data quality needs to be investigated
- The EDM is undergoing planned maintenance
- The EDM has communications issues which means we are not currently receiving data from the monitor
The map currently shows Scottish Water monitored overflows for which we can report data in near real-time. We will continue to review the information available and may update this in the future.
The map does not include unmonitored overflows at this time.
If an overflow has a Planned Investment Priority of ‘None’, either studies have indicated that no improvement was required or the need for a study has not yet been agreed and the overflow has not been assessed.
Where required, studies have been undertaken to prioritise unsatisfactory sewer overflows for phased improvement, further information on investment prioritisation can be found at Prioritisation of Sewer Overflows in Scotland. Where studies confirm there is a need for improvement, we will agree priorities with our environmental regulator, the Scottish Environment Protection Agency (SEPA).
The need for studies is agreed with SEPA and is based on receiving water classification information. The River Basin Management Plan (RBMP) for Scotland 2021 - 2027.
Event Duration Monitors (EDMs) only provide the start and stop times, and duration of overflows events. They do not provide volume information.
In some cases, we are required to report volume or an estimated volume, which is why this is included in the published reported data.
Overflow FAQs
If you would like to know more about overflows and how they work, you can find more commonly asked questions on the link below.
More Info
