Serving parts of North West London and the Home Counties.

Groundwater levels

South East Region


South East water levels hydrograph

*The long term average (LTA) has been calculated statistically, using the long term data record for this hydrograph. The respective drought zones are used as operational triggers, and have been derived using the LTA.

*Drought zone 1 is the LTA in South East region.


In Southeast region, groundwater levels are currently in drought zone 1, below the level recorded at the end of April 2018. Levels saw a substantial recovery during December 2018, followed by a reduced rate of recovery between January and March 2019 and a declining trend through April in line with the LTA. Rainfall for the month was very low (32% of the LTA). For the recharge period as a whole (October to April inclusive), rainfall has been 89% of the LTA, with rainfall during November, December and March being in excess of 130% of the LTA.

Groundwater levels are expected to decline until autumn 2019 if they follow the LTA trend. Under a 100% rainfall scenario, we anticipate levels will remain in drought zone 1 for the remainder of the year. Lower rainfall scenarios (such as 60% or 80% of the LTA) may see us crossing drought zone 2 in autumn 2019. Even under these lower rainfall scenarios, groundwater levels would likely remain above those of autumn 2017.