Mogden sewage treatment works

Mogden Sewage Treatment Works is key to protecting public health and the environment. Each day, we treat wastewater from homes and businesses. We clean it carefully before returning it safely to rivers and waterways.

We take pride in our environmental efforts and operations. Our teams work hard to meet strict standards. We constantly invest in improvements to reduce noise, odour, and other impacts. We know that living near a treatment works raises questions. That's why we're committed to being a good neighbour and minimising disruption to the community.

This webpage is for residents near Mogden. It provides updates on site activity, planned work, and improvement projects. You'll also find information on how we connect with the local community.

Before February 2026, odour and sludge gas readings were reported separately. 

London Borough of Hounslow site inspections

The local Environmental Health Officer is welcome to carry out a site visit whenever they wish. Following each visit, any observations are sent to the management team at Mogden for review and, when necessary, appropriate actions are taken.

Managing mosquitoes at Mogden

We also follow a strict programme of inspections and treatment aimed at controlling mosquitoes at Mogden. The processes we use are audited by local environmental health officers, and based on recommendations from leading independent experts. We also work with the London boroughs of Hounslow and Richmond upon Thames to raise public awareness of mosquito breeding sites in the wider local area and how to prevent further breeding to reduce the numbers.

Storm flows from Mogden

When it rains, the high volume of sewage, or wastewater, coming into Mogden can't all be treated at once. The excess is stored in storm tanks after first being screened and de-gritted.

Once the flow reduces, the sewage is returned to the head of the works for processing. However, if the storm tanks fill up before this happens, we have no option but to send partially treated excess wastewater to the River Thames. This prevents it backing up into streets or homes.

You can view real-time data for our storm discharges on our EDM map.

Mogden residents meetings

We work closely with the local community surrounding Mogden Sewage Treatment Works and have held regular Mogden residents meetings since 1992. The meetings invite local councillors, MPs and residents to discuss any issues they may be experiencing as a direct result of living near the treatment works. All previous residents' meetings are available to download below:

Iver South

Iver South is a sludge de-watering centre, approximately 10 miles from Mogden. Sludge is pasteurised, digested, then sent through the sludge pipeline to Iver South. Here, it is de-watered using polymer and then made into cake. This is used for agricultural purposes across the country.

Our aim is to carry out our operation with minimal disruption to our neighbours. Given the nature of our operation, there are times when things can go wrong. With this in mind, you'll find any notifications on this page. These will also be sent to registered residents and stakeholders.