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Private drains and sewers transfer - six years on

October 2011 marked a major change in the way sewers and drains running from private properties into the public sewer system were managed, as water companies took over responsibility for many of these assets. As we pass the sixth anniversary of the transfer, Andy Brierley of Lanes Utilities - Thames Water's wastewater network services maintenance partner - reviews its continuing impact

by Andy Brierley, Framework Technical Director, Lanes Group

The private sewers and drains (PDAS) transfer, which started in October 2011 was a major change in the way sewer systems were maintained in the UK. But, arguably, it happened with the general public barely noticing.

While the owners of individual properties were responsible for maintaining all drain and sewer pipes leading from their properties into public sewers, many of them – householders especially – barely realised this was the case.

It only became apparent when things went wrong. Then, they faced potentially very large repair bills to put things right.

After the PDAS transfer, private property owners have remained responsible for maintaining sewer pipes within their property boundaries, as long as they only service their property. But once the pipe leaves their property, it became the responsibility of the local water company to maintain it.

This was a big change. The size of the wastewater network managed by water companies doubled overnight. Many of the drainage assets were old, inaccessible and in bad condition. Most of them were also unmapped.
This represented a major challenge for water companies. The amount of effort needed to bring these assets up to a good standard has been phenomenal. At the same time, the water regulator, Ofwat, through its CSAT system, has continued to set a very high bar for service quality standards.

So, has PDAS turned out to have been a positive thing for the UK’s water infrastructure? Perhaps the best way to answer that is to ask a number of other key questions about PDAS, six years on.

Q: Is there clarity among industry players about who is responsible for what part of the wastewater network?

A: Water companies themselves are very clear on ownership, and certainly understanding has developed well since the transfer. However, managing such a vast and complex network will always cause some uncertainties. Utility companies recognise there is an ongoing need for education over responsibilities.
We still regularly deal with issues on ownership, and work with Thames Water and customers to resolve them. It’s about being respectful and helpful in terms of resolving matters in a sensible way. We all understand we want to work together for the long-term benefit of the whole community when it comes to managing and sustaining vital resources.

Q: Has the PDAS transfer resulted in a higher quality wastewater network?

A: The answer is a most definite yes. We now have a higher quality network and can plan more strategically and effectively for future improvements. It’s a similar proposition to the telephone and digital media industries, which are moving towards a full fibre-optic system. There is no point having excellent main sewers, if the connections from homes and businesses are substandard.

The PDAS transfer has put a lot of pressure on water companies as they have had to invest many millions to bring these previously neglected sections of the network up to standard, and we’re still uncovering examples of sub-standard drainage that attracts substantial sums of investment to put right. However, major progress has been made in a short period of time.

Q: Could the system have coped if the change had not been made?

A: Given the standards set by Ofwat, and the increasing pressure on the network from population growth and changing ways demands are placed on the system, the answer to that has to be no. Having end-to-end responsibility for the network is giving water companies access to huge amounts of extra data that is allowing them to manage wastewater more intelligently and strategically.

We are now beginning to use this data to predict and manage blockage hotspots during heavy rainfall, to programme preventative maintenance and inform capital investment, so money is spent wisely and goes further.

However, there is still a significant way to go before we can make full use of the data. Many previously private sewers and lateral drains, known as S105A sewers, are still to be mapped. There is limited uniformity in their layout and function.

This means we are still learning on a case-by-case basis how they function as part of the wider network. When we have a complete 360-degree view of large sections of the system, this data-driven maintenance programming will really come into its own.

Q: Is the insurance sector happy with current system?

A: What insurance companies want is reduced risk, and being able to manage drainage and sewer networks more effectively, with better long-term planning, will reduce risk, so they must be happier. That is not to say there will not still be problems along the way, such as localised flooding, that causes damage to property.
Population growth and other changing demands placed on wastewater management are expected to increase pressure on the wastewater system over the next decade. These issues make it even more important to manage the network end-to-end, something that PDAS is allowing us to do. We are better placed now to calculate and respond to risks associated with the potential for critical failure of the wastewater network.

Q: Do customers get a good deal?

A: Yes, they do get a good deal, for sure. Ofwat is a robust regulator, that sets high standards and demands good value for money for people who pay their water bills. At the same time, customers, like insurance companies, experience much less uncertainty and delay when it comes to resolving drain and sewer problems.

In the Thames Water region, they have to make one call, and it is answered promptly. A highly capable drainage engineer or whole team, where required, is dispatched, with the latest specialist equipment. The problem is sorted quickly and effectively, according to clear performance standards, and they are kept informed of progress at all times.

Before the PDAS transfer, the problem may have been resolved through an insurance claim. Or they may have had to manage what could be a substantial repair project themselves, and then foot a large bill at the end of it. It really adds value for customers.

Q: Have job volumes now settled, indicating water companies have got to grips with maintenance regimes?

A: The experience with the PDAS transfer has been pretty similar across the UK. There has been major growth in wastewater maintenance work as water companies have geared up to get to grips with S105A sewers. In the Thames Water catchment, the volume of work relating to 105 code sewers peaked a couple of years ago, but the overall volume of wastewater maintenance work continues to rise.

Q: What next for wastewater network maintenance?

A: This is the exciting part of the previous question. As already mentioned, the huge volume of data gathered during the maintenance process will underpin the next phase of development in WNS management.

The data we gather is being used by Thames Water via predictive tools to plan resources more effectively and respond to the extreme events that put communities under the greatest strain. Increasingly, artificial intelligence systems will guide this process and offer additional value.

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