Serving parts of North West London and the Home Counties.


Our Water Resources

 Last Update: 4 September 2017


Groundwater levels: below average

Over the last year, there has been low rainfall and the water in our aquifers (porous rock where groundwater is stored) and rivers that we use to supply your water has dropped below average.

This is important as 60% of the water we supply to you comes from underground sources and aquifers only usually fill up from rainfall during autumn and winter when there is less plant growth and evaporation.


We have welcomed the rainfall between May and August. This has 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 our autumn and winter recharge season.

The long term below average rainfall means we have not seen the usual rise in groundwater levels that we would usually expect.

We continue to monitor the situation closely with clear plans in place to make sure we’re fully prepared, should we experience another dry autumn and winter in 2017 / 18.

For more information and FREE water saving devices, please visit


Here is a graph showing the average rainfall levels for the past year: 



Groundwater levels

Here is a diagram showing our current groundwater levels



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

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