Animal disease outbreak: prevent pollution from cleaning and disinfection 13.4.2026 | Her Majesty's Revenue and Customs How to store and dispose of washwater when cleaning and disinfecting after an animal disease outbreak. Cleaning (cleansing) and disinfecting after an outbreak of animal disease (for example, salmonella or avian flu) produces more washwater with higher concentrations of disinfectant than routine cleaning. This guidance helps you: follow pollution prevention rules when you clean and disinfect reduce the cost of disinfectant washwater storage and disposal follow the law on washwater disposal How to clean and disinfect If a notifiable disease is confirmed on your premises, the Animal and Plant Health Agency (APHA) will advise you on cleaning standards and options you can take. In most notifiable disease outbreaks, the occupier of the premises will be responsible for cleansing and disinfection and its cost. You must follow the instructions the APHA officer gives you on how to do this. You must use a disinfectant approved by Defra for the disease. Free-range poultry farms If you clean and disinfect a free-range poultry farm, move poultry sheds to an area where you can contain the washwater, where possible. How to dispose of washwater You should use one of following methods to dispose of washwater, listed in order of preference. Option 1: Drain to a foul sewer (best option) The most environmentally-friendly option is to discharge washwater from cleaning and disinfecting to a foul sewer. You must get approval from your wastewater service supplier before you discharge disinfectant washwater to a foul sewer. Option 2: Use a registered waste carrier If you choose this option, you must fulfil your business or commercial waste disposal responsibilities. These include checking your carrier is registered to dispose of waste and not allowing them to dispose of your waste illegally. Option 3: Dispose on to land You must have an environmental permit to carry out landspreading, unless the Environment Agency says you do not need one. If you want to dispose of washwater by landspreading, you must contact the Environment Agency first. They will then tell you if you need to apply for a permit or not. Start now You must not landspread disinfectant washwater until the Environment Agency has either: confirmed you do not need a permit granted you a permit APHA may also ask you to store washwater for a set time period before landspreading. Environmental permit application forms If you need to apply for a permit, you should follow the guidance on environmental permits for discharges to surface water and groundwater. This includes details of the application forms you must fill in and how to submit them. You must dispose of washwater at least: 10 metres (m) from rivers, streams and field ditches 30m from streams with nature conservation status 50m from boreholes, wells and springs used for drinking water or food production purposes 250m from solution features, such as sinkholes, swallow holes, swallets Permit applications for landspreading disinfectant washwater can take up to 20 working days. You must pay an application fee. How much you pay will depend on the volume and materials used. The Environment Agency will advise you how much you need to pay after they have received your permit application. How to store washwater before disposal If you need to store disinfectant washwater before you dispose of it, use your existing dirty water or effluent management storage systems if you can. Make sure existing drains that serve yards and livestock buildings connect to the effluent management system. Unconnected drains can lead to uncontrolled polluting discharges. If you clean and disinfect areas that are not connected to your storage system, you can: redirect existing drains lay new drains build temporary storage Slurry stores You should avoid using a slurry store for disinfectant washwater. If you add disinfectant washwater to a slurry store, all of the disinfectant washwater will become waste. In this case, you must apply for an environmental permit to landspread the entire contents of the store. Check how much storage you need During an animal disease outbreak, you’ll produce more washwater than normal from: biosecurity cleaning vehicle and equipment washing during culling preliminary cleaning and disinfection secondary cleaning and disinfection To calculate how much washwater storage you need, consider the: water flow rate of the pressure washer you use average rainfall for your area that falls into open stores, or on to hard surfaced areas that drain into stores Build temporary storage You must agree the location and construction of temporary washwater storage systems with the Environment Agency before you build them. If you build a temporary lagoon, you must meet the rules for storing silage, slurry and agricultural fuel oil (known as SSAFO). The temporary lagoon must: be 10m from watercourses or ditches be 50m from wells, springs or boreholes used for drinking water or food production have a base above the water table have a gap of at least 750 millimetres between the surface of the lagoon’s content and the top of the lagoon wall have a liner, unless there’s at least 1m of clay subsoil below the base have liners made from butyl rubber or plastic (PVC or high or low density polyethylene) not use a low grade liner in a high risk groundwater area (you can check where these areas are on Magic map) Using temporary storage Avoid filling earth bank stores above ground level. You must not use temporary washwater storage for more than 12 months. Your responsibilities when storing and disposing of washwater The Environment Agency will provide advice, recommendations and authorisations on what you can do at your premises to make sure you lawfully dispose of your washwater. You could face enforcement action and get an unlimited fine if you allow washwater or disinfectant to cause pollution by allowing it to enter: groundwater through uncontrolled seepage through the ground surface waters – for example, ditches, rivers, coastal waters You must fulfil your business or commercial waste disposal responsibilities. If you do not, you could face enforcement action and get an unlimited fine. https://www.gov.uk/guidance/animal-disease-outbreak-prevent-pollution-from-cleaning-and-disinfection