Water and wastewater services for Kent, Sussex, Hampshire and the Isle of Wight
Your area

Find out if you're a Southern Water customer, check your water quality, or explore our interactive map to see what's going on in your area

Your area

Find out if Southern Water supplies your home, check your water quality or explore what's happening in your area.

Need help?

Type your question into the box below or see what other customers often ask.

Portsmouth flood alleviation scheme

We've completed a £20 million project to reduce the risk of sewer flooding in parts of Portsmouth and Southsea.

Portsmouth was one of the first cities in the UK to have a dedicated sewer network. It was built during the Victorian age, when sewers were designed to take both rainwater and wastewater from people’s homes.

These sewers are known as combined sewers and during storms there can be up to 25 times more water in them than during dry weather.

Diverting rainwater

Our scheme diverts a significant amount of rainwater – up to 6,400 litres per second – away from the combined sewers by sending it into the sea.

We have also constructed two new underground pumping stations, which will reduce the risk of sewer flooding.

Work started in October 2012 at various locations across the city. The work will benefit the whole city but in particular those areas that have suffered flooding in the past.

Our leaflet explains how we manage wastewater in the Portsmouth area.

The wider benefit

By taking rainwater from the system it will also benefit the environment by reducing the amount of water flowing to Eastney Pumping Station.

During heavy rain the pumping station releases stormwater from an outfall at Fort Cumberland to prevent flooding.

In 2015, we completed a £10 million investment scheme to improve the resilience and robustness of our storm tanks at Fort Cumberland.


At Eastney Pumping Station, a number of improvements are taking place to make the site run as efficiently as possible.

This includes a 'real time' monitoring system to give more reliable warning of storms and allow preparations to be made at the pumping station.

Other work at Eastney includes:

  • The installation of an odour control system
  • Refurbishment of pumps
  • Upgrading of the site control system.
  Close box