Discharges to water and sewer
If you pollute water or cause or risk causing environmental damage to water, you are committing an offence.
What you must do
Get authorisation to discharge to surface waters and groundwater
You must get authorisation from your environmental regulator before you discharge anything other than uncontaminated water to surface water or groundwater. You must comply with all of the conditions of your authorisation or you may be prosecuted and fined.
Your authorisation could be:
- in England and Wales, an environmental permit or registered exemption
- in Northern Ireland, a discharge consent, groundwater authorisation or pollution prevention and control (PPC) permit
- in Scotland, an authorisation under the Controlled Activity Regulations (CAR) or a pollution prevention and control (PPC) permit.
In Scotland, certain discharges to surface water are automatically authorised by general binding rules (GBR). In these cases, you do not need to apply for authorisation from SEPA, but you must comply with the conditions of the GBR. You can check to see if your discharges are covered by a GBR in the CAR practical guide.
SEPA: CAR practical guide (Adobe PDF - 540KB)
In England and Wales you can register an exemption from an environmental permit with the Environment Agency. Under the exemption you can discharge from a septic tank or package sewage treatment plant:
- 5 cubic metres (m³) or less of treated sewage effluent per day to surface waters
- 2 cubic metres (m³) or less of treated sewage effluent per day to groundwater.
You must comply with all the conditions of your exemption.
To qualify for the exemption your septic tank or sewage treatment plant must be:
- designed and installed correctly, and
- maintained regularly to reduce the risk of pollution.
See our guidance on water pollution in:
England on Business Link: Preventing water pollution
Northern Ireland on NIBusinessInfo: Preventing water pollution
Scotland on Business Gateway: Preventing water pollution
Wales on Business.Wales.gov.uk: Preventing water pollution
If you want to register or check the conditions of your exemption contact the Environment Agency.
Environment Agency: Contact us
If you need to construct a new outfall structure for a discharge:
- in England and Wales, you may need to get a flood defence consent from the Environment Agency
- in Northern Ireland you may need consent from the Rivers Agency, and you should contact your local office for further information
- in Scotland your discharge authorisation will cover any construction.
Environment Agency: Flood defence consents
Rivers Agency: Area offices
Get permission to discharge to public sewers
You must get permission from your water and sewerage company or authority before you discharge anything to their drainage system. If you are a tenant you may need your landlord’s permission to connect to a private surface water drain.
Water UK: Water and sewage operators
A public foul sewer collects foul water (sewage and trade effluent) only. A surface water sewer collects surface water drainage only. A public combined sewer collects both foul and surface water drainage.
You can discharge:
- sewage from domestic facilities, eg toilets, basins and kitchens, to a public foul sewer or to a public combined sewer
- trade effluent to a public foul sewer or to a public combined sewer
- clean uncontaminated water to a separate surface water sewer or to a public combined sewer.
Before you release trade effluent into a public sewer you must have a trade effluent consent or enter into a trade effluent agreement with your water and sewerage company or authority. Once you have a consent, you must comply with its conditions.
See our guidance on trade effluent in:
England on Business Link: Discharging trade effluent
Northern Ireland on NIBusinessInfo: Discharging trade effluent
Scotland on Business Gateway: Discharging trade effluent
Wales on Business.Wales.gov.uk: Discharging trade effluent
You do not need permission to discharge sewage from domestic facilities to the nearest public foul sewer or to a public combined sewer. If you have any concerns about your discharges to sewer, contact your water and sewerage company or authority.
Water UK: Water and sewage operators
If your business is in an area where you can not be connected to a public sewer, you may have a septic tank or package treatment plant. See pollution prevention guideline (PPG) 4 for guidance. However, you should connect to a public sewer if it is possible.
PPG 4 Treatment and disposal of sewage where no foul sewer is available (Adobe PDF - 244KB)
Prevent environmental damage
Water pollution can be classed as environmental damage in some circumstances.
You must prevent and remediate environmental damage that occurs from water pollution caused by your business activities. If anyone else reports environmental damage as a result of your activities, your enforcing authority will have to investigate. For more information see our guidance on environmental damage in:
England on Business Link: What is environmental damage?
Northern Ireland on NIBusinessInfo: What is environmental damage?
Scotland on Business Gateway: What is environmental damage?
Wales on Business.Wales.gov.uk: What is environmental damage?
Good practice
Store hazardous materials and chemicals safely
Store any hazardous materials, fuel, oil or chemicals safely and in an area where you can contain spills. This may be a legal requirement if you store oil in England, Northern Ireland or Scotland. This should be within a secondary containment system (SCS) such as:
- an impermeable bunded area
- a bunded pallet or spill pallet
- a sump pallet
- a bunded storage unit
- a bunded drum store
- a storage cabinet with an integral sump.
Your bund and any bunded pallets should be able to contain at least 110% of the volume of the largest tank or 25% of the total volume you are likely to store, whichever is greater.
Follow the pollution prevention guidelines (PPGs)
Follow the PPGs to avoid causing pollution. This is particularly important if your business is in an area that has vulnerable groundwater.
All pollution prevention guidelines
In England and Wales, groundwater source protection zones (SPZs) have been set up to protect groundwater used for drinking water supplies. To find out if you are in an SPZ, enter your postcode on the Environment Agency’s website ‘What’s in my backyard?’.
Environment Agency: What’s in my backyard? - Drinking water
In Northern Ireland, you can find out if you are in an area where groundwater is particularly vulnerable by using the GeoIndex tool on the British Geological Survey (BGS) website.
BGS: GeoIndex – Northern Ireland map scheme
In Scotland, contact your environmental regulator to find out if you are in an area where groundwater is particularly vulnerable.
Contact your environmental regulator
Label your drainage system
Keep an up-to-date and accurate drainage plan of your site. This will help you and your staff identify the locations of all the drains and sewers and where they lead.
Colour code your drainage system by painting manhole covers, gullies and grills using a recognised colour coding system: blue for surface water drains and red for foul water drains. This will help you to identify which system you are discharging to and also where any spills will end up.
If you store oil or fuel on your site, consider installing oil separators in your surface water drainage system. These will trap oil from contaminated run-off, which you can empty from the separator.
PPG 3 Use and design of oil separators in surface water drainage systems (Adobe PDF - 78.6KB)
Supervise deliveries
Supervise deliveries of materials and fuels to your site.
Clearly label tanks with their contents and storage capacity and provide a method for measuring the amount in the tank. This will reduce the risk of overfilling and spills.
Deal with spills
Keep absorbent materials such as sand and other containment equipment suitable for the type and quantity of fuel, oil and chemicals you store and use on your site. Keep them close to where you might need them, particularly in delivery areas. Make sure that your staff know where they are and how to use them. You can buy spill kits containing appropriate spill equipment for the substances you store.
Report pollution incidents as soon as they happen to the environmental regulators’ UK-wide incident hotline on 0800 80 70 60.
Prepare a pollution incident response plan for dealing with spills. Make sure that your staff are familiar with the plan and know how to implement it.
PPG 21 Pollution incident response planning (Adobe PDF - 318KB)
