Commentary

Public Water Supplies - Water abstracted and supplied (Ml/d)(1) : 2002/03 to 2016/17

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In Scotland, before 2006 there were limited forms of control on abstraction and impoundment. Ministers were able to make Water Orders to give powers to water authorities to abstract water for public water supply. Since April 2006, the Water Environment (Controlled Activities) (Scotland) Regulations have taken effect and abstractions and impoundments for water supply now require authorisation by SEPA. It is a condition of authorisation that water should be used efficiently.

Trends

Between 2002 and 2009, estimated raw water abstractions by Scottish Water decreased by 13% to 2,165 Ml/d. Between 2010 and 2016, using improved data and methodology, the volume of raw water abstracted decreased by another 13% to 1,826 Ml/d.

Between 2002/03 and 2016/17, treated water produced fell by 593 Ml/d (25%) to 1,785 Ml/d. This decrease in treated water is almost entirely due to a reduction in leakage of 573 Ml/d (51%) to 559 Ml/d over the same period. The total leakage reported in the table has increased by 28 Ml/d since last year. Using established ISO9001 Water Balance methodologies, Scottish Water also reports bottom-up and MLE leakage in the WIC Annual Return submission both of which reduced in 2016/17. Scottish Water continues to investigate the imbalance between top down and bottom up estimates of leakage and is currently in the process of delivering a phased data and reporting improvement action plan across a number of key areas. The Economic Level of Leakage (ELL) was attained in 2012/13, and Scottish Water continues to manage leakage at the ELL.

Operational use increased by 53 Ml/d between 2002/03 and 2007/08 to a peak of 71 Ml/d. It has since decreased by 18 Ml/d to 53 Ml/d in 2016/17. Reported domestic water consumption has increased by 11 % between 2002/03 and 2016/17, it should be noted improved data and methodologies have been used in later years. At the same time non-domestic water consumption has decreased by 24% over the same period. When looking at all water consumption combined (operational use, domestic and non-domestic consumption), between 2002/03 and 2016/17 it has reduced by just over 1.5%.

Targets

As indicated above, having attained the ELL in 2012/13, one year ahead of regulatory expectation. Scottish Water is currently maintaining leakage at the ELL. The ELL is the point where it is more costly to repair a leak than the cost saving due to the value of the water leaking from the system. Managing leakage at the ELL benefits both customers by optimising the cost of providing water services and reducing the risk of drought impact and the risk to the environment from reduced raw water abstraction. The ELL target level is periodically updated and will be recalculated in advance of the next regulatory period.