Southern Water is warning that it may need to apply for a drought permit by the start of September, if hot and dry weather continues in August.

Current forecasting takes into account the fact the flows in the River Test, in Southampton, Hampshire, are falling.

The River Test is a vital source of fresh water for south Hampshire and a designated river due to its high environmental value. A drought permit would be necessary to help protect the environment and health of the river and a legal requirement to continue to abstract flows when river levels are low.

Demand for water has been higher this year due to more people staying at home during the Covid-19 crisis and the hot and dry periods of weather through the spring and summer.

If there is sufficient rainfall, demand for water reduces and flows in the river recover, the possibility of applying for a drought permit will be reduced. The water company said it would continue to monitor the situation closely with the Environment Agency.

Southern Water is urging all its customers in Hampshire to reduce water use wherever possible, to help reduce the impact on the river’s habitat.

Changes to Southern Water’s abstraction licences on the River Test and River Itchen and predicted future changes mean a shortfall of about 190Ml/d during a 1-in-200-year drought to meet the forecast demand for water – about 80-85% of the amount needed to supply customers in the south Hampshire area.

The potential frequent need for a Testwood Drought Permit is brought about by the Testwood abstraction licence change in March 2019, which includes a new flow condition that stops abstraction when river flow falls below 355 Ml/d. This is necessary to protect the river system.

Southern Water has agreed with the Environment Agency to rely on Drought Permits and Drought Orders up until 2027 to allow it to continue to take water from the rivers during dry weather, while it invests in new water resources under its Water for Life – Hampshire programme.