The South East’s water companies have been encouraged by the government to work together more closely to boost regional supply in the updated planning blueprint for the sector.

The government published its draft national policy statement (NPS) on water last week, paving the way for the construction of a new generation of reservoirs and water transfers between regions.

“To meet future needs, water resource infrastructure will be required to supplement demand management action,” says the NPS, pointing to the National Infrastructure Commission’s recent report stating that at least 3,300 megalitres per day of additional capacity in the water supply system is required by 2050 in order to maintain the current level of resilience.

The increased demand is being fuelled by a combination of climate change and population growth.

It says that by the 2030s a quarter of England’s “water resource zones” are expected have a supply demand deficit of greater than 5 Ml/day.

The NPS says the government expects neighbouring water companies to work together when planning resources, pointing as an example to the development of the Water Resources in the South East group of regional suppliers.

It says that while this group already focuses on trading supplies it may need to focus on more strategic transfer options to address longer term pressures.

New reservoirs can also help to increase the level of transfers of water between regions that have a surplus, like the north and the west, and those that are in deficit, like the South East.

“This high degree of regional variability highlights the need for a more strategic approach to managing water resources,” says the NPS.

The NPS says new reservoirs are likely to play an “important role” in providing a good level of resilience during a short-term drought lasting two years or less.

But reservoirs must be planned “well in advance” of when they are needed, as they take around ten years to plan and build before being able to supply water.

No new large reservoirs have been built in England since privatisation.

In her foreword to the NPS, water minister Therese Coffey stresses that the proposals on boosting supply had to be viewed in the context of the government’s efforts to cut leaks.

“Even if we are successful in reducing demand and the water industry halves the amount it loses through leaks, we will still need more water for supply.

“This might be new reservoirs, more water transfers, desalination or making better use of waste water.”

The NPS covers new reservoirs, water transfer infrastructure and desalination plants with the capacity to deploy more than 80Ml/day.