A threat to our rivers: plumbing misconnections

Did you know that your local river is likely to contain chemicals from detergents, household cleaners and possibly even sewage –  because houses in your area have been plumbed incorrectly?

Pollution from misconnected plumbing is damaging all our urban rivers and, in some cases, it is the top reason why our rivers and beaches are failing to meet good water quality standards.

Misconnected plumbing is common in areas which have a separate drainage system of two drains – the foul drain, for dirty household water, and the surface water drain for rainwater; the standard arrangement in houses built after the 1920s.

It’s estimated that 1 in 5 properties have a misconnection of some sort.  The most common misconnected items are washing machines (35%), followed by sinks (10-15%), dishwashers (10-15%), toilets (5%), and even whole houses (5%).

When drainage pipes carrying foul water are mistakenly connected to surface water drains, the contaminated dirty water flows straight into the nearest river or stream without being treated.

washing machine discharging into river
The results of washing machine discharges into the Houndsden Gutter, a tributary of the Salmons Brook in Enfield

Household cleaners, toiletries, and even sewage from misconnected toilets end up in our rivers because of incorrect plumbing.  The affected waterways cannot sustain wildlife and often contain e-coli bacteria. They look and smell unpleasant, so people are put off visiting them.


dead stream due to pollution from misconnections
Dead stream due to pollution from misconnections

Here at Thames21, we believe everyone has the right to enjoy a clean, healthy local river, so we’re spreading awareness of the problem and working on projects to reduce pollution in affected areas. Here’s how you can help too, with three easy steps:

  1. Please check your property for misconnections. You can find out how to do this on the ConnectRight website. If you find a misconnection, get it rectified by a WaterSafe quality assured plumber.
  2. You can spread the word to family and friends, as public awareness of this problem is low.
  3. If you’re enjoying a stroll or a cycle along a stream or river and you see pollution, please report it to the Environment Agency by calling 0800 807060.