Reliability and availability 2013-14

We use a wide variety of other information to assess risks to customers – and decide whether we need to take action on your behalf. This is part of our approach for holding water companies to account.

Below we highlight the overall performance of the monopoly water and sewerage and water only companies in England and Wales in 2013-14 – and any action we are taking to protect customers’ interests.

Reliability and availability indicators

In 2013-14, all of the companies met their targets for reducing water leaks from their networks. The level of leakage, although slightly higher than in 2012-13, was still around its lowest level since records began in the early 1990s.

During 2013-14 there were no restrictions in place on water use. Overall, companies were able to provide us with reassurance that they were able to supply enough water to meet their customers’ needs. Find out more about why water companies sometimes need to restrict water supplies.

Each company is required to maintain its assets (such as water and sewerage treatment works, and underground networks of water mains and sewers) to a certain standard so that it can provide reliable services to you over the long term ‒ and protect the environment. We call this ‘stable serviceability’.

When a company is not maintaining its assets effectively, there will be a rise in the number of incidents such as burst water mains or sewers overflowing. So it is important they get it right.

Companies have told us that overall they maintained their assets to a sufficient standard in 2013-14.

Action we are taking

Companies that had less than stable (‘marginal’) serviceability are seeking to restore assets to stable serviceability. We are reviewing their progress with these action plans as part of the 2014 price review. This includes clawing back money for customers where companies have not restored their performance. You can read more about this in our draft determinations.


We have collated below the performance data companies have published.

Serviceability water non-infrastructureServiceability water infrastructureServiceability for sewerage non-infrastructureServiceability sewerage infrastructureLeakageSecurity of supply index (SoSI)
Northumbrian (Essex and Suffolk)58100
Affinity Water
 – Central areaSTABLESTABLE170100
 – East areaSTABLESTABLE4100
 – Southeast areaSTABLESTABLE7100
Sembcorp BournemouthSTABLESTABLE21100
South Staffs (Cambridge)STABLESTABLE13100
South StaffsSTABLESTABLE67100
Sutton & East SurreySTABLESTABLE24100

Green means the company’s performance is in line with or better than expected
Amber means the company’s performance is not in line with expectations but performance has slipped only slightly
Red means the company’s performance is significantly below target or expectation
Blue means companies did not have to submit this data