Serving parts of North West London and the Home Counties.


Our Water Resources

 Last Update: 10 November 2017


We have now entered our critical recharge period (October to March) when we expect rainfall to reach the aquifers (porous rock where groundwater is stored) that we use to supply your water.

Unfortunately, the amount of rain we received in October fell considerably short of what is usually expected and our water resources remain below average.

Looking ahead, we will need an above average amount of rainfall during this recharge period before we start to see groundwater return to average levels.

Here is a graph showing the average v long term average rainfall for the past year.


Aquifers only usually fill up from rainfall during autumn and winter when there is less plant growth and evaporation.

We welcomed the rainfall between May and September, this benefited the environment and helped reduce the demand for water. However, this was limited in comparison to the low rainfall over the last year, particularly during the autumn and winter recharge season, which typically runs from October to March.


Groundwater levels

Here is a diagram showing our current groundwater levels



It's important we all save water

Please click here for water saving tips and free water saving devices


What we're doing

We operate in areas which are designated as suffering from serious water stress* and we face a growing population. We need leave more water in the environment, whilst making sure we have enough water. We can only do this by working in partnership with our customers to reduce demand for water.

Over the last two years we have made significant investments in driving down leakage whilst helping our customers use less water. This includes:

  • Offering practical help to our customers to save water, energy and money through our FREE Home Water Efficiency Checks with every meter fitted in our Water Saving Programme

  • FREE water efficiency devices offered to all our customers and launch of our ‘Keep track of the tap’ campaign.

  • Driving down the level of leakage on our network beyond the target set by our regulator, Ofwat

  • Increasing our investment to renew our network to help prevent leaks and bursts.

  • Our Education Team engages with thousands of students a year in schools and at our Education Centre in Bushey to enrich school curriculums and promote water efficiency.

* The Secretary of State for the Environment, Food and Rural Affairs under Regulation 4 of the Water Industry (Prescribed Conditions) Regulations 1999, as amended. To find out more about our water saving programme, please visit