Study shows metering's immediate effect on water use habits

Economists Dr Mirco Tonin and Dr Carmine Ornaghi have been working with Southern Water to examine the impact of the company’s five year Universal Metering Programme (UMP). They examined the consumption habits of more than 200,000 UMP customers over a period of four years from 2010. The researchers found that in total customers were making water savings of more than one and a half times the predicted 10%.

The research also shows that people cut down their consumption very early in the switching process, even though metered charges aren’t activated until after three months. In the second month after the installation of a meter, consumers saved an average of 37 litres per day. In the third month, they saved an average of 50 litres per day. The reductions continued after metered charges kicked in, albeit at a slower pace, reaching an average saving of almost 70 litres after the fourth bill – or two years of metering.

The researchers examined four different stages of switching to a metered programme: meter installation and switch of contract; the first three months after switch of contract; the first bill after switching; and subsequent bills every six months. By comparing data with households not in the UMP programme, they were able to compensate for seasonal differences in water consumption, geographic variations and economic conditions. 

Dr Tonin commented: “Overall, we find a strong decrease in water consumption due to the UMP. But what is particularly remarkable from a behavioural perspective is that households start reducing their consumption as soon as the meter is installed – even though they do not immediately have financial incentives to do so, due to the three month ‘grace period’ between installation and switch of contract. This could well be because households take into account that it takes time to change consumption habits, or because the installation focuses their attention on water consumption.”

“We would like to thank our customers for their support and efforts in reducing water usage. Across the region, by the end of the five-year programme, customers will be saving more than 30 million units of water every day, commented Susan Stockwell, Chief Customer Officer, Southern Water. “We’re delighted with the results of this independent research which has studied water usage across a huge sample of households. It confirms that the majority of customers are changing their behaviour and reducing their bills.”

These results will be updated as new data become available, and the Southampton researchers will continue their work by exploring the motivations behind consumers’ water saving actions in more depth.