Most people believe that everything they pour down the sink or flush down the drain is cleaned up by water companies before it reaches our rivers. The truth is very different.

Friends of the Thames has launched its new public awareness campaign — Rethink the Sink — in response to scientific evidence showing that everyday chemicals, pathogens, and even recreational drugs are flowing directly into rivers and seas 24 hours a day, seven days a week.

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This is not new science — but it is research very few people know about. For years, scientists have warned that our wastewater systems are incapable of removing most of the synthetic chemicals used in modern life. The result is an invisible chemical cocktail entering the Thames and waterways across the UK every single day. Some 350,000 regulated chemicals go into our waterways every single day, only around 40 of which are tested for by the Environment Agency.

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What is going down the drain?

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• Bleach and antibacterial cleaners release chlorinated compounds that kill essential river microbes.
   

• Fabric softeners and detergents emit quaternary ammonium compounds (QACs) and surfactants that damage fish gills, alter sediment health, and fuel antibiotic resistance.
   

• Synthetic fragrances and preservatives — such as phthalates, parabens, and synthetic musks — persist through treatment and act as endocrine disruptors, affecting fish and amphibian reproduction.
   

• Toothpaste ingredients like fluoride, triclosan, and artificial sweeteners remain detectable downstream of treatment plants.
   

Microplastics and older chemical residues are still being found in riverbeds, despite bans years ago.

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Members of the public are invited to pledge to Rethink their Sink through the Friends of the Thames website. By signing the pledge, individuals, households, schools, and businesses can commit to making small but powerful changes — such as switching to biodegradable cleaning products, reducing the use of bleach and antibacterial sprays, and avoiding synthetic fragrances. Every pledge is recorded on the campaign website, creating a visible wave of action across communities and demonstrating growing public demand for cleaner, healthier waterways. Together, these individual choices will add up to a collective movement for change — proving that when we all rethink what goes down the drain, we can make a real difference from source to sea.

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Cited Research:

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To ensure the campaign stands up to scrutiny, Friends of the Thames has cited the following independent research and data sources:

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Regulated Chemicals, Environmental Science & Technology:  https://pubs.acs.org/doi/10.1021/acs.est.9b06379

 

Statista (2024) – Leading brands of household cleaners in the United Kingdom.
Available at: https://www.statista.com/statistics/304000/leading-brands-of-household-cleaners-in-the-uk/
 

American Lung Association (2021) – Volatile Organic Compounds (VOCs) in Household Cleaning Products.
Available at: https://www.lung.org/getmedia/f844533f-9513-4eb4-814c-2302265302c4/VOCs-in-Household-Cleaning-Products.pdf
 

U.S. Environmental Protection Agency (EPA) – Wastewater Technology Fact Sheet: Chlorine Disinfection.
Available at: https://www.epa.gov/sites/default/files/2015-06/documents/chlorine-disinfection.pdf

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