South East Rivers Trust

Drain misconnections and our rivers


A guest blog written by Jennifer Connelly

According to the Department for Environment, Food and Rural Affairs, there are still an estimated 150,000 to 500,000 UK homes with misconnected drains. Dodgy pipework or old houses with out of date plumbing can cause wastewater to end up in our rivers and seas, creating serious problems for wildlife. So what are drain misconnections, what causes them and how do they affect our environment?

What is a drain or pipe misconnection?

Most homes in the UK are connected to two main sewers – a wastewater sewer and a surface water sewer. A wastewater sewer is where drainage from your appliances such as showers and toilets will go to be treated at a wastewater treatment plant. Whereas surface water, such as rainwater and roof and ground runoffs, will be piped directly to a river or stream, without being treated.

It is possible for the two kinds of pipe to become misconnected, which means that the dirty wastewater from your toilet or shower could end up in a local river, without being treated. River pollution then occurs when the wastewater from your toilet and appliances drains into the wrong sewers, carrying it into streams and rivers and contaminating freshwater with chemicals and even faeces. Clean water pipes can also become misconnected – this can overload the wastewater sewer and cause flooding. This is why it’s so important to check your drains are not misconnected, avoiding any nasty sewage problems later on.

What causes a drain misconnection?

A drain misconnection can occur as a result of dodgy or incorrect plumbing, but this is not always the case. Older properties commonly have misconnected drains without property owners being aware, which is why it’s so important to check your drains if you’re buying a new property or if they haven’t been checked before.

Wastewater management company UKDN Waterflow have created a whitepaper on illegal drainage to help homeowners identify drain misconnections – you can read it here. If you leave your drain misconnection unaddressed, it could land you with a hefty £50,000 fine or even imprisonment in extreme cases – which is why it’s so important to check!

How does this damage the environment?

Rivers can become polluted with chemicals when the wastewater from your home (for example, from washing machines, sinks and dishwashers) is drained into the wrong sewer which leads into rivers and streams.

If you ever pour bleach or other harsh chemicals down the sink into a misconnected drain, these chemicals can end up in rivers and seas, and cause harm to fish and other aquatic life. This is even bigger concern for those who consume fish from contaminated rivers or seas, as the harsh chemicals can find a way back to you through eating the fish that were affected.

In the UK, it is reported that 14.1% of people flush wet wipes, 10.6% of people flush tampons and applicators and 5.3% of people flush cotton buds, according to a report by UKDN Waterflow. These commonly flushed items can often bypass the filtering systems at wastewater treatment plants and therefore end up in rivers and eventually the ocean. However, in the case of a misconnection, these items can also get into rivers and streams – threatening wildlife and contributing to plastic pollution and litter found in our rivers.  Even if your drains are not misconnected, it’s important to only ever flush the three P’s – pee, poo and paper. Anything else should be discarded in the bin.

How can you help?

In addition to checking your own property doesn’t have any misconnected drainage you can join the South East Rivers Trust on an Outfall Safari survey. This is a great way to spot misconnected outfalls and ensure they are reported to the water company responsible for fixing them.

The South East Rivers Trust’s next Outfall Safari will be taking place during March with a training session for volunteers wanting to get involved being held on 3 March 2020. For full details please check out our Events Page.

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