Britain's 21 million pet cats and dogs rely on flea and tick treatments. But ministers and veterinary bodies are now asking owners to think about what happens after application, as chemicals from some popular spot-on products are being found in rivers and streams. The new national campaign does not tell people to stop protecting their animals. It makes a practical point: these medicines matter for pet and public health, yet the way they are used can decide how much of the product stays on the animal and how much reaches the water.

Monitoring by the Environment Agency has detected fipronil and imidacloprid in UK waterways at levels that could harm aquatic insects, including mayflies and dragonflies. That matters because it shows water quality can be shaped not only by highly visible sources of pollution, but also by routine household choices. Research funded by the Veterinary Medicines Directorate found that these substances can enter waterways through wastewater and when recently treated pets swim in natural water. The case for action is immediate and evidence-led: small changes at home can cut avoidable losses without weakening parasite control.

The official message is built around three words: Plan. Apply. Protect. In practice, that starts before the pipette is opened. If a pet needs washing, the better option is to do it in the days before treatment rather than straight afterwards, when the medicine is still settling on the skin. Owners are also being advised to choose a time when close contact will be limited, such as in the evening or before leaving for work. That bit of planning helps the treatment dry properly and lowers the chance of product being spread onto hands, furniture or bedding.

Application itself is another weak point. The Veterinary Medicines Directorate says owners should read the leaflet carefully, or check its Product Information Database, and part the fur until the skin is visible. Spot-on medicines are designed for the skin, not the coat. That may sound straightforward, but the campaign is clearly responding to a common problem: treatments are not always used exactly as directed. When that happens, owners risk wasting the product, reducing its effect, and increasing the chance that residues are washed away.

The strongest environmental advice comes after treatment. Owners should avoid touching the application site until it is dry and keep pets out of rivers, lakes and other natural waters for at least four days. The campaign also suggests limiting swimming and washing in the weeks that follow. Disposal matters too. Used pipettes should go in the bin, not down the sink and not into household recycling. Unused or expired medicines should be returned through the right routes after checking with a vet or medicine supplier, rather than cleared out like ordinary waste.

There is another detail that many people will not have considered: fur from treated animals should also go in the bin rather than be left outside for nesting birds. It is a modest change, but it fits the wider purpose of the campaign. The aim is not perfection. It is to stop small losses of product from adding up across millions of households. For owners who cannot easily follow these steps, or who think a treatment is not working, the advice is to speak to a vet or medicine supplier before making changes. That keeps the message grounded in animal welfare as well as water quality.

Abigail Seager, chief executive of the Veterinary Medicines Directorate, has presented the campaign as a way to help people get the most from spot-on treatments while reducing harm to waterways. Other partners are backing the same line. RUMA Companion Animal and Equine says responsible use of parasiticides should be a priority, while Professor Jason Weeks, chair of the Pharmaceuticals in the Environment Group, says small changes in everyday use can make a real difference. That backing matters because this is not a one-off awareness push. The campaign sits inside the government's wider work on pharmaceuticals in the environment, led by the cross-government Pharmaceuticals in the Environment Group, which has already published a roadmap on chemicals from pet flea and tick treatments in UK waterways.

A policy review is now moving alongside the public advice. The Veterinary Medicines Directorate opened a call for evidence on 16 April 2026 and plans to close it on 11 June 2026 as it considers whether veterinary medicines containing fipronil and imidacloprid should require professional advice at the point of sale. The useful takeaway is that better water protection is not only about new infrastructure or tougher enforcement. Sometimes it starts with clearer labelling, better retail advice and a few careful decisions at home. The government's Be Spot On Aware campaign also includes free materials for vets, retailers, groomers and medicine suppliers, giving this guidance a real chance to become everyday habit rather than another forgotten leaflet.