It Is Illegal To Pour Anything But Rainwater Into Road Gullies

You see it on every street: those iron grates set into the kerb, known as gully pots or storm drains. Perhaps you’ve just finished cleaning your paintbrushes, or you have a pan of old engine oil to get rid of. It might seem harmless to pour it down the drain, thinking it just… disappears.

But it doesn’t disappear. And what you might see as a convenient disposal method is, in fact, a criminal act that causes serious harm to our environment.

The Crucial Difference: There’s No “Treatment”

The most important thing to understand is where that drain leads. The water from your sinks, toilets, and showers flows into the foul sewer, which goes to a treatment works to be cleaned before it’s returned to the environment.

Road gullies are different. They are part of the surface water system, designed solely for rainwater. This water runs directly—and completely untreated—into our local streams, rivers, and lakes. Anything you pour down that gully ends up polluting our precious blue spaces and harming the wildlife that calls them home.

What You Must Never Pour Down a Gully

The rule is simple: Only Rain Down the Drain. Any other liquid is a pollutant. This includes:

• Engine oil, diesel, and petrol: Even a small amount can form a film on the water’s surface, preventing oxygen from getting in and suffocating fish and insects.
• Paint, white spirit, and thinners: These are packed with toxic chemicals that are poisonous to aquatic life.
• Cement and construction slurry: This can block drains completely and, once in the river, coats the riverbed, destroying habitats for invertebrates and fish eggs.
• Soapy water from washing your car: The detergents contain phosphates that cause algal blooms, which deplete oxygen and choke waterways.
• Cooking oil and fat: These solidify, blocking drains and causing localised flooding. In rivers, they decompose and remove vital oxygen from the water.

It’s Not Just Wrong, It’s Illegal

Pouring polluting liquids into a road gully isn’t just an environmental misstep; it’s against the law. Under the Environmental Protection Act 1990 and the Water Resources Act 1991, it is a criminal offence to “cause or knowingly permit” any poisonous, noxious, or polluting matter to enter controlled waters.

The consequences are severe:

• Unlimited fines for the most serious cases in the Crown Court.
• Substantial fines in a magistrates’ court.
• A criminal record.
• Being billed for the clean-up costs, which can run into tens of thousands of pounds.

The Environment Agency (and its equivalents in Scotland, Wales and Northern Ireland) actively investigates pollution incidents and will not hesitate to prosecute individuals or businesses caught in the act.

What You Should Do Instead

We all have a responsibility to protect our waterways. The correct way to dispose of hazardous liquids is straightforward:

1. Use Your Local Household Waste Recycling Centre (HWRC): Your local tip has dedicated, safe collection points for used engine oil, chemicals, paint, and other hazardous waste. It’s free for household quantities.
2. Contain Spillages: If you have an accidental spillage of oil or chemicals, use absorbent materials like sand or cat litter to soak it up. Do not hose it into the gutter. Place the contaminated material in a sealed bag and dispose of it with your general waste or at the HWRC.
3. Be Smart About Washing Your Car: Use a commercial car wash, where the water is recycled and treated, or wash your car on a grassy area where the ground can filter the water naturally.

A Simple Plea for Our Waterways

Our rivers and streams are vital havens for wildlife and places of beauty for us all to enjoy. The next time you have a waste liquid to dispose of, remember: that road gully is not a sink. It is a direct pipe to the natural world.

Let’s work together to keep our rivers clean and our consciences clear. Remember: Only Rain Down the Drain.