The Environment Agency has a campaign called Yellow Fish, and it has a clear message: “Only rain down the drain!”

The campaign looks to provide information and practical advice through events and giving out materials in order to raise awareness of how people can change their behaviours and help to reduce the amount of pollution that ends up in our rivers and oceans.

Wiltshire Wildlife Trust’s Water Team has linked up with the Environment Agency to help disseminate this information in Wiltshire, and we have started with a Yellow Fish project in Swindon.

Why is it important?

Wiltshire hosts some of the most beautiful and rare river habitats in the country, and all rivers are home of a wide array of wildlife species including birds such as kingfishers, mammals such as water voles and otters, fish such as Atlantic salmon and brown trout, and a whole host of plants, invertebrates and other species. Did you know that only 0.5% of the earth´s surface is covered with freshwaters but that they are habitat for over 10% of all animals and over 35% of all vertebrates?

In addition, despite 70% of the earth being covered with water, 97.5% of this is salt water, 2% is frozen, and just 0.5% is freshwater. Only 0.007% of this water is safe for consumption, and this is shared by 7 billion people! Therefore, we need to look after our rivers and waterbodies so that wildlife and humans alike can survive.

However, pollution caused by humans is a major threat to our watercourses, the quality of aquatic habitats and the safety of our drinking water.

Did you know?

  • Around half of all ocean pollution is caused by sewage and waste water. Each year, the world generates 5–10 billion tons of industrial waste, much of which is pumped untreated into rivers, oceans, and other waterways.

  • Road and surface water drains are designed to carry only rainwater usually to the nearest watercourse. Allowing engine oil, cooking oil, paints, chemical wastes, detergents and even litter to enter these drains causes pollution to enter the receiving watercourse. The effects of these pollutants can range from looking horrible to large scale killing of fish and wildlife.

  • One litre of oil can pollute one million litres of drinking water.

  • Soils and sands entering drains can cause sediment pollutions in rivers, negatively affecting fish spawning areas.

  • Different pollutants will affect watercourses in different ways:

    • Sewage, grey water and cooking oils and fats can all cause water oxygen levels to decrease due to high Biochemical (Biological) Oxygen Demand (BOD), suffocating and killing the wildlife that lives there and impacting animals further up the food chain.

    • Fats, oils, and grease (FOG) come from meats, butters and margarine, lard, food scraps, sauces, salad dressings, dairy products, and cooking oil. When FOG goes down the drain, it hardens and causes sewer pipes to clog. This can lead to a sanitary sewer overflow where raw sewage actually backs up into your home, lawn, neighbourhood, and streets. Not only does this nasty mess cause health issues, it also can run into a nearby stream or river, which affects our drinking water.

    • A plastic bottle can survive an estimated 450 years in the sea and plastic fishing line can last up to 600 years. Plastics present a major hazard to seabirds, fish, and other aquatic creatures. For example, plastic fishing lines and other debris can strangle or choke fish.

Pollutants can also build up in the food chain and can eventually end up affecting humans. For example, people can get diseases such as hepatitis by eating seafood that has been poisoned.

So far, we have...

…Marked stormwater drains with a yellow fish symbol in Rivermead Industrial Estate to remind businesses that anything they put down the drains can cause direct contamination of the rivers and other waterbodies that the drains flow in to.

…visited Nova Hreod Academy to deliver an education session to 160 year 7 students to explain the project to them and get them thinking about how they can reduce pollution by not putting certain things down drains, sinks and toilets.

…used social media to highlight the project.

What can we all do to help?

  • Spread the word! Making people aware of the problem is the first step to solving it.

  • There are over 30 million cars in the UK and keeping them clean can impact on water quality if they are washed over surface water sewers. Avoid washing your car or wheelie bin on the street as soap and chemicals can go down the drain and pollute watercourses.

  • Do not put or allow substances like engine oil, paint, detergents or litter down road and surface water drains.

  • Do not put litter, oil, milk, wet wipes (even if they say they are flushable), microbeads, detergents or medication down internal drains/toilets. Instead, you can:

    • Take medication back to the pharmacy

    • Wipe excess fat out of cooking pans

    • Pour used oil into a jar rather than the sink

    • Buy chemical free/eco-friendly detergents and toiletries

    • Avoid using products containing microbeads

    • Pull hair out of the plughole  

    • Only wash DIRTY clothes to limit the number of plastics and microfibers contained in the clothes going down the drain from the washing machine

Report pollution incidents to the Environmental Agency Incident Hotline on 0800 80 70 60, which is free of charge to call and open 24 hours a day, 7 days a week.

Further information

There is also a campaign being run by Wessex Water called Operation Streamclean, which was established to help reduce the pollution going into local streams by looking for misconnections (domestic drains that are plumbed incorrectly). To find out more about this project, please visit

WWT Water Team

Volunteers for any of our projects are always welcome; our projects are always lots of fun, very satisfying and a great way to meet new people. Check out our latest volunteering opportunities here: 

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