Sewage Data HQ guide

Sewage Data HQ is the go-to hub where you can access real-time sewage discharge data from across England. We’re putting all the facts, figures and answers in one place for you.

What is Sewage Data HQ?

More information means more power for you to understand and act. But sewage data can be tricky to interpret. That’s why we’re making it clear and accessible.

Our mission is simple: to provide accurate, unbiased data from an organisation that always puts water users like you first. This is a crucial step in making sewage discharge data transparent and actionable.

So dive in, stay informed and be part of the change. And if you have further questions, get in touch or read more.

What’s the difference between the Safer Seas & Rivers Service and the Sewage Map?

The Safer Seas and Rivers Service (SSRS) is an alert service designed to inform water users when water quality is compromised, helping you decide whether it’s safe to enter the water. It works by using water companies and regulators real-time data to provide accurate risk assessments, giving you clear alerts about water safety based on up-to-date information.

In contrast, the Sewage Map is not an alert service. It shows the operational status of sewage overflows across the country, but it doesn’t provide enough context to help you assess whether it’s safe to enter the water. While it tells you where sewage overflows are, it doesn’t indicate where the discharge may affect water quality or pose a risk to human health.

Understanding these differences is important. It highlights why we need a national sewage alert system, not just access to public data that doesn’t serve water users’ safety needs.

Safer Seas and River’s Service FAQs

The Safer Seas and Rivers Service app puts real-time water quality and beach safety information at your fingertips. Providing alerts for over 550 locations across the UK, the app alerts users to real-time sewage discharges and pollution risks around the UK. As of 2024, we are now adding locations that don’t receive any alert to highlight where you can swim in the UK, but these locations will be called ‘dormant’ as we don’t know anything about the water quality in real-time.
The Safer Seas and Rivers Service uses real-time data from a combination of sources.

Water companies in England and Wales voluntarily provide us with real-time sewage alerts from sensors located on their Combined Sewer Overflows (CSOs), which then automatically send alerts to the Safer Seas and Rivers Service.

In addition to the sewage alerts during the bathing season, Pollution Risk Forecasts (PRFs) are issued by the four regulators in the UK.

IconExplanation
No Water Quality Alert in Place
We are receiving data for this location and have no indications of reduced water quality. However, we cannot confirm safety from non-sewage pollution and advise checking for visible signs of pollution.
Dormant
We have no real-time information about this location, but it has been identified as a popular bathing location. This location will always be dormant unless data is shared with SAS about the water quality in this location.
Poor Annual Classification
If bathing water received a ‘poor’ rating by the regulator, bathing is not advised and a permanent alert will be in place.
Out of Season
Water quality data is not available as the site is out of season. This only applies to locations that receive alerts from the regulators. Water companies provide sewage alerts all year round.  
Pollution Risk Forecast (PRF)
Bathing is not advised due to the likelihood of reduced water quality. Pollution Risk Forecasts use rainfall or other factors such as tidal information to assess the risk of a temporary reduction in bathing water quality. 

Forecasts are issued around 9:00 am every morning and we keep the alert up for 24 hours. 

These alerts are only available during the bathing season:

England and Wales: 15 May – 30 September

Northern Ireland and Scotland: 1 June – 15 September
Pollution Incident
There has been a confirmed incident at this location and bathing is not advised. For example, an oil spill, burst sewage pipe or algae bloom. This data comes from the environmental regulators and will often indicate a beach closure.

When an incident alert is in place, more information about the specific event will be displayed within the location profile. 
Maintenance
The systems that are responsible for this location's alert are under maintenance and the water company/regulator has temporarily disabled real-time alerts. 

Maintenance alerts in Scotland refer to the period between 10:00 pm and 9:00 am when no active forecast is in place.
Location impacted by a Sewage Discharge
There has been a confirmed discharge near this location within the last 48 hours. This symbol will be in place whilst the discharge is active and will then remain in place for 48 hours after the discharge has stopped. See the location page for more information about the discharge. The level of information you will be able to see will vary depending on if your water company is sharing this with Surfers Against Sewage.

Welsh Water, Thames Water and Southern Water are sharing information with us about each sewage discharge which means you can see exactly where the discharge took place, how long it went on for and how many locations it impacted. To do this, you can be interactive with the map on the ‘locations’ page and click on individual CSOs.

All other water companies in England are choosing to not share this data with Surfers Against Sewage, so you will only see when a location is impacted but without more details. They are publishing this data on their own websites and therefore we see this as a huge barrier to transparency, as it means water users can’t fully assess the risks through our app.

Scottish Water and Northern Ireland do not provide us with sewage pollution alerts.
CSO discharged in the last 48 hours
CSO under maintenance
CSO actively discharging
CSO has not discharged in the last 48 hours

In 2022, DEFRA published the Storm Overflow Reduction plan which states that “all water companies must provide data about the frequency and duration of storm overflows in near real-time and make this available to the public no later than 2025”.

The status of all combined sewer overflows (CSOs) is now available on our sewage map – but this map is not an alert service. We can only add data to the Safer Seas and Rivers Service we have an indication of the impact the discharge is having, and we only have this information for bathing waters.

If your chosen location is on the app, the SSRS should still be used to assess whether it’s safe to swim. If the location you swim/surf/paddle isn’t on the SSRS OR if you plan to go further away from the bathing water (e.g. to kayak round to another cove or along a river), you can use this online map to see the activity of CSOs in the wider area.

We’re actively collaborating on a groundbreaking project to establish a national standard and definition for sewage alerts. Once this standard is determined, it will bring clarity to the sector, reducing confusion about which source provides the most accurate information and which service to rely on.

IconDecription
Location is a designated bathing water
Location is popular for open water swimming
Location is popular for surfing
Location is popular for kayaking
Location is popular for sailing
Location is popular for paddleboarding
Dogs are allowed all year round
Dogs are prohibited during summer or restricted to certain areas. Check for local guidance
There is a summer lifeguard service at this location. Check for local guidance on season dates
There are toilet facilities at this location
There is camping nearby to this location
There is a café nearby
Tide times are provided for that day
Wind
Water temperature
Wave Height

Our coverage is determined by which locations water companies provide us with Sewage Discharge Alerts for, or where Pollution Risk Forecasts are issued.

We have introduced a status called ‘dormant’ which means we can add any location to the SSRS even if there is no data for this location. Adding a location as ‘dormant’ is a great first step to getting an active alert. It means we can flag these locations to water companies and investigate if there is sewage impacting the location.

Although we show a record of past incidents at each location, the Safer Seas & Rivers Service is primarily designed to provide real-time water quality information.

Detailed historical data from water samples can be found here:
England 
Wales 
Scotland 
Northern Ireland

During periods of reduced water quality, there is a risk of contracting infections from bacteria and viruses associated with faecal matter.

During periods of poor water quality, entering the water could put you at risk of contracting eye, ear, skin and throat infections, gastroenteritis, E. coli and hepatitis. For further information on these conditions please visit our page on “The risks of mixing with sewage”.

The Safer Seas and Rivers Service aims to provide you with the information needed to make an informed decision on whether to enter the water. We cannot guarantee your safety and can take no responsibility for any sickness or injury associated with entering the water.

If you have experienced being sick after entering the water, please refer to a medical professional immediately. You can also help us build our case study bank by reporting your sickness via our sickness report form, so we can hold those responsible to account. 

Collect Evidence:

  • Document the incident with photos or videos.
  • Note down the location, date, and time (and smell!).
  • Gather as much information as possible about the source and extent of the pollution.

Contact the Regulator:

Report the incident to the relevant environmental regulator using their 24-hour hotline numbers:

  • England, Scotland, and Northern Ireland: 0800 80 70 60
  • Wales: 0300 065 3000

Or use their online forms to submit evidence:

Following these steps ensures that the incident is properly documented and reported to the authorities who can act.

Designated bathing waters are locations popular with water users and designated under the Bathing Water Regulations 2013 which outlines waters suitable for bathing other than swimming pools. The water quality regulators are responsible for monitoring designated bathing waters. Official bathing waters may receive pollution risk forecasts or sewage discharge notifications, or both. You can find this information in the ‘details’ section of the location.

Unofficial bathing waters are locations which haven’t been designated. These locations may still be popular with recreational water users but the water quality is not regularly checked and therefore does not have an annual classification. The source and impact of pollution at these locations may be unknown. Environmental regulators do not provide pollution risk forecasts for these locations, however, sewage discharge notifications are provided by water companies as a precaution.

Any coastal or inland water that is popular with bathers can be designated if it fulfils the criteria set out by DEFRA. If your favourite swimming location isn’t designated and you’d like to find out more about the process and how we can support you, you can find out more here.

Water levels in oceans, seas, bays and rivers fluctuate with the tides due to the gravitational pull of the sun, moon and other planets. We can predict future water levels based on past observations because the frequencies of gravitational forces are well-known.

The tide times included in the app are provided by World Tides. We can’t guarantee these will always be accurate due to the complex modelling of some locations. If you spot a consistent issue with tide times at your local beach – please report it to us by emailing [email protected].

Whilst tide times are crucial for planning your visit to the beach, we suggest you also check local webcams and be prepared for tide times to vary from the information provided through tide time providers. Only swim when it is safe to do so.

In September 2022, Southern Water launched a new update to its real-time alert system, Beachbuoy, incorporating data modelling to predict if a Combined Sewer Overflow was impacting bathing waters.

Southern Water still display the discharge on their map and in their data table, but the location icons only change colour when they determine it has impacted, based on release location, duration and tidal state. 

Surfers Against Sewage have chosen not to adopt the modelled impact generated by Southern Water and display alerts based on whether there is a confirmed discharge at one of the sewer overflows. We feel the impact modelling is not sufficient to be substituted for our current approach and it is due to this, you may notice a difference between what the Safer Seas and River Service displays when compared with Southern Water’s map. 

We welcome efforts to improve the understanding of the impacts of sewage discharges on water quality but we require further reassurance that the tidal modelling is sufficient. We will be reviewing Southern Water’s modelling as it develops, and as they undertake an independent review to provide more reassurance.  

The Anglian Water storm overflows are fitted with monitoring devices, with data fed into a telemetry system called ‘BeachAware’. BeachAware then adds an additional layer of analysis that calculates the volume of storm water being discharged alongside a coastal model that factors tidal conditions. The system then predicts how the overflow will impact bathing water quality. If it predicts a reduction in bathing water quality below the ‘Sufficient’ standard at relevant nearby beaches, an alert is automatically generated and we issue a sewage alert on the app.

Anglian Water’s model (BeachAware) calculates the volume of storm water being discharged alongside a coastal model that factors tidal conditions. A sewage alert is only raised if the system predicts a reduction in bathing water quality below the ‘Sufficient’ standard at relevant nearby beaches. Therefore, not all sewage discharges will result in BeachAware alerts, for example when the tide is taking the discharge in the opposite direction to a bathing area. This means you may see an overflow operating but no sewage alert in place. This may also result in a time difference between storm overflows and the issuing of BeachAware alerts, as tides may initially move any plume away from the designated bathing water.

SAS remove an alert after a 48 hour period with no further modelled impacts on water quality. Anglian Water use 24 hours.

We’ve marked some locations as “dormant” because they’re recognized as popular swimming spots by local water users. However, we can’t issue alerts for these areas until we receive data from either the water company or the regulator. We’re constantly pushing for more data on the impacts to recreational waters and collaborating with the industry to create a standard sewage pollution alert. This will bring consistency across the sector and make it easier for us to issue alerts.

While some data may be available through sources like water company regional maps, these maps only show the status of CSOs (combined sewer overflows). They don’t provide alerts or give a clear picture of the potential risk. You can use this data if no alert is available but do so with caution.

Bathing Waters
Although this location is designated, the EA don’t provide a pollution forecast as they have been unable to model the location. This location will have undergone an environmental impact assessment and will have determined that no sewage overflows impact this location. It will receive incident alerts from the EA, but these are abnormal events and therefore we feel it’s misleading to put a green tick on this location because we don’t have access to any daily data.

Non Bathing Waters
Since this location isn’t designated, the regulator is not required to provide a predictive alert for water quality. Because it hasn’t been designated, there hasn’t been a full impact assessment, leaving the effects of sewage discharges on human health here completely unknown. There may be sewage overflows nearby, but we can’t issue an alert unless we have evidence that the overflow is having an impact. While information about all overflows can be helpful for understanding the situation, assessing the risk ultimately relies on individual and local knowledge of the area.

The Surfers Against Sewage (SAS) Safer Seas and Rivers Service (SSRS) has been designed to provide water users with the latest pollution alerts and forecasts compiled from UK Water Companies and Environmental Regulators in hundreds of locations across the UK. Currently, the SSRS keeps alerts live for 48 hours post-discharge. In order to ensure that we are maintaining our responsibility to water users by alerting them of risk, whilst also acknowledging the impact of alerts on water users’ behaviour and wellbeing combined with impact on local businesses, it is important that our alerting system is based off the best available evidence.

UK water companies keep pollution alerts issued for varying periods, generally between 12-48 hours. Given this information, it is recommended that a safe ‘catch all’ recommendation is used which accounts for variability in pollution dispersal and the potential for pollution to remain at unsafe levels for substantial periods of time following a discharge. It is therefore recommended for the safety of water users, SAS follow the precautionary approach to keep the current alerting system in place at 48 hours.

The Safer Seas and Rivers Service aims to provide you with the information needed to make an informed decision on whether to enter the water. We cannot guarantee your safety and can take no responsibility for any sickness or injury associated with entering the water. If you have experienced being sick after entering the water, please refer to a medical professional immediately. You can also help us build our case study bank by reporting your sickness via our sickness report form, so we can hold those responsible to account.

Live Sewage Map FAQs

For England, we source data directly from the Water UK API, ensuring it reflects the information reported by English water companies. However, the reliability of some reported spills can be uncertain. Certain triggers, such as overly sensitive monitors, may activate discharge alerts even when no actual spill has occurred. Given the near real-time nature of this data, it is important to note that not all information will always be 100% accurate.

For Welsh Water, data is not shared via a public API. However, we access this information through a feed provided directly by Welsh Water.

Scottish data is now live via their own public map. While we have requested a data feed from Scottish Water, we have been able to source the necessary data independently to include it in our map. We remain committed to working with Scottish Water to establish a public API to ensure more streamlined and accessible data sharing.

Currently, real-time sewage discharge data from Northern Ireland is not included on the Sewage Map. Northern Ireland Water, a government-owned company, is the only water utility in the UK not yet providing this information. We are actively engaging with Northern Ireland Water to explore how we can gain access to this critical discharge data.

Although Event Duration Monitoring (EDM) data is available in Northern Ireland, it cannot currently be integrated into our map. As soon as any compatible data becomes accessible, we will ensure it is published on the map.

It’s important to note that Northern Ireland has not been subject to the same legal requirements as England to produce and share this type of data.

We’re making sewage history—literally.

Our new sewage map now includes a full history for every recorded overflow in England, something water companies and the national map won’t show you. Why? Maybe it’s because they don’t want you to see the full amount of sewage discharges? Now, you can view and export overflow data by the week, month, storm period, or any timeframe you choose—no more waiting a whole year for the official numbers. We believe every spill should be logged in real-time, and by making this data accessible, we’re exposing the shocking frequency of sewage spills.

Disclaimer:

The data presented here is sourced from the National Storm Overflow Hub data feed. While we aim to provide the most up-to-date and accessible information, we cannot guarantee the accuracy of this data due to occasional inconsistencies in the feed. Only the annual verified data can provide definitive figures on historical discharge durations and frequencies. Discrepancies in the data highlight the need for greater transparency and accountability in real-time sewage reporting.

Yes, the public data feed’s steering group will continue working on improvements, such as better verification processes to reduce false alerts. Additionally, we’re involved in a UK water industry research project to create a national sewage alert system. This will allow us to provide alerts for locations not currently covered by the Safer Seas and Rivers Service, improving the accuracy of data and making it easier to decide if it’s safe to swim.

Yes, all APIs feeding into this map are publicly available. You can find them here.

At Surfers Against Sewage, we understand the power of data in raising awareness about the impact of sewage discharges on local waterways. However, using data effectively in campaigns can be tricky and prone to misinterpretation if not handled properly. We’re here to help! Our team is ready to support you in using this data for your campaign. While all map data is freely available, we also offer expertise to ensure you’re using it correctly and powerfully. If you have specific questions or need guidance, don’t hesitate to get in touch with us.

This map displays all available data on combined sewer overflows (CSOs) in the UK. However, not every overflow is included due to differences in monitoring and data availability across the four nations.

Northern Ireland

There is no real-time monitoring of CSOs in Northern Ireland, so we do not have data to display.

Wales

Welsh Water currently provides data for a portion of their CSOs and is gradually expanding coverage. By the end of 2025, they plan to include all remaining monitored CSOs. However, emergency overflows are not included in their dataset. Hafren Dyfrdwy, the other water company in Wales, does not yet have a data feed available for real-time monitoring.

Scotland

Scottish Water has improved its CSO monitoring but does not yet have full real-time coverage. Emergency overflows are not included in their data.

England

England is the only UK nation where 100% of CSOs are legally required to be monitored, so we can display all of them on the map. However, while some emergency overflows are monitored and publicly available in certain areas, this data is not yet accessible for us to use. Water companies in England are in the process of rolling out EDM (Event Duration Monitoring) for emergency overflows, and these will be added to the map once finalised.

For detailed explanations on what the sewage data represents and its impact, check out the comprehensive FAQs on the Water UK Portal. Surfers Against Sewage contributed to this resource, providing insights into the data source and its meaning. Explore the FAQs here: Storm Overflows FAQs | Stream – Portal.