Information has been emerging since March 2026 about a possible water‑supply issue affecting parts of East Hampshire served by South East Water.
Residents have been asking questions about this topic, so we’ve put together these Q&As to answer the most common ones and help keep everyone up to date.
What is the ‘water’ issue?
The availability of water in the northern part of the East Hampshire including the Alton and Four Marks area, has come under increasing scrutiny following South East Water's response to Basingstoke and Deane Borough Council’s Regulation 18 Local Plan consultation in March 2026.
South East Water stated that the area known as WRZ4-W which covers Basingstoke and extends into Hart and parts of Alton and the surrounding area - is forecast to face a supply-demand deficit. In simple terms, this means that the amount of water available, much of it drawn from local chalk aquifers, is not expected to keep pace with local growth.
The issue is not that homes and businesses have run out of water today. Rather, it is about whether there will be enough water available in the future to provide a secure and reliable supply for existing customers while also supporting new homes, employment development and community facilities.
Over time, increasing demand for water, environmental restrictions on water abstraction, and the effects of hotter and drier weather have placed growing pressure on available supplies. As a result, South East Water has advised that additional investment is needed to improve the resilience of the network and secure future supplies.
This has created an important planning issue because local authorities need to be satisfied that new development can be supported by adequate infrastructure. The council is therefore working closely with South East Water, the Environment Agency, Natural England and neighbouring authorities to understand the implications of the water supply constraints and the solutions being developed. This will help ensure that future growth can be planned and delivered in a sustainable way while maintaining a secure water supply for existing residents and businesses.
How has the water issue developed?
The water supply issue in the WRZ4-W area has developed gradually over many years. More people and businesses need water, while at the same time there are tighter environmental rules on how much water can be taken from rivers and underground sources. Hotter, drier weather and longer periods without rainfall have also increased pressure on available supplies.
As a result, South East Water has identified that, in parts of this area, there is currently insufficient water available to both maintain a secure supply for existing customers and support all planned future growth without further investment in new water infrastructure. Addressing the issue will require a combination of water network improvements, new supply schemes and measures to reduce water demand.
What area does this affect?
Please see map of WRZ4-W.
How does it affect residents living in the affected area?
South East Water reassured the council in June 2026 that there is no immediate threat to the water supply.
The concern is that pressure from new development in the future could impact on the secure supply for existing customers, if infrastructure improvements are not put in place.
What does it mean for future development?
As the Local Planning Authority, the council needs to understand the relevant material planning considerations when making decisions. Where there are concerns about future water supply, this is a material planning consideration. For local plans and future development, this is an infrastructure constraint that requires further research, and could potentially influence the future phasing of development.
While this does mean the council takes a closer look at this issue when determining applications, it does not necessarily mean that applications will be refused on this basis.
What is the council doing to gather more information?
The council is working hard to establish the facts, and seek information from the organisations involved, particularly South East Water, Environment Agency and Natural England.
The Council is actively participating in cross-organisation steering group meetings, involving the affected authorities (Hart, Basingstoke and Deane, South Downs National Park and East Hampshire), Environment Agency, South East Water, Natural England and Defra.
The affected authorities have met with a top KC and jointly commissioned written legal advice to help inform decision making.
The Leader of the Council has written to the Chief Executive of South East Water, requesting an urgent meeting.
The Council is presently not determining applications for new homes or commercial development within the affected area, while we seek further information. We are also consulting the Environment Agency, Natural England and South East Water on all pending applications in the affected area while continuing to develop a robust and legally defensible position.
Once legal advice has been received and considered, the Council will provide further information when there is a meaningful update.