Meeting the private sewer challenge

Water and sewerage companies need to prepare for the imminent Private Sewers Transfer, Martyn Hopkinson, WaSC development & operational director at UK Drainage Network, explains how

As of 1 October 2011, responsibility for over 200,000km of lateral drains and private sewers will be transferred from property owners to the water and sewerage companies (WaSCs) in England and Wales.

With these assets unmapped, and in unknown condition, this sudden shift of responsibility will present serious challenges to the WaSCs, who will see their remit increase dramatically overnight.

The exact impact this will have on workloads is unknown – but it is clear that this will not be ‘business as usual’ for the WaSCs. They will need to adapt to a very different way of working – both with regards to the types of drainage repair that will need to be carried out, and the very high levels of customer service levels required.

They will also need to develop systems that will allow them to effectively manage their dramatically increased volume of assets.


Private drains and the public sewer system have several key differences. First, private drains are mainly small in diameter, meaning that blockage levels are likely to be higher than on the existing public network.

In some parts of the country, the presence of pitch fibre drains, laid from the late fifties until the seventies, as a cheaper alternative to clay pipes, can also cause complications.

This material is particularly susceptible to deformation because of its low structural strength and due to inappropriate installation techniques.

This can also lead to a particularly high level of blockages and, while re-rounding and lining can be an effective short-term solution, in many instances large-scale replacement will provide the only real solution – resulting in a further cost burden on both WaSCs and their customers.

Drainage problems in private sewers are also exacerbated by the fact they are typically situated next to human dwellings. Proximity to gardens means that root ingress is more likely, and an ‘out of sight, out of mind’ mentality amongst private owners often means that problems with drainage are not addressed until the problem becomes critical and major repair work needs to be undertaken. A lack of awareness of how to prevent damage to drainage also means that misuse through the disposal of inappropriate items such as nappies, fats, oils and greases through the system is all too common.


The old adage that prevention is better than cure is appropriate here, and we can expect WaSCs to take a much more strategic approach with regards the prevention of drainage problems.

Preventing problems with public drainage is as much an awareness issue as a practical issue. Until now, private sewers have been a private problem, with property owners dealing with them individually – either by paying for the problem to be fixed themselves, or requesting that the repair or maintenance work is carried out as part of a household insurance claim.

Because of this, advice regarding proper drainage maintenance has also been provided in a rather piecemeal way and typically only after a problem has surfaced. With the ‘centralisation’ of the issue will come a renewed focus on raising awareness of how private owners can – often very simply – minimise inconvenience to themselves by preventing damage to the sewers on their own property.

In time this leads to a reduced need for repair and replacement of sewers and drains. We can also expect WaSCs to take a strategic approach to drain and sewer maintenance.

Proactive management

It will be ultimately much more cost effective in the long term to manage these assets proactively, rather than waiting for problems to surface. It would seem clear that for the WaSCs it is likely to be much more cost effective in the long term to manage drains and sewers proactively rather than repeatedly sending crews out to keep unblocking the same pipes without establishing and resolving the root cause of the problem.

Indeed, this will be imperative, as two key performance indicators set by Ofwat will be both reducing overall blockage numbers, and reducing repeat visits to the same problem. In order to do this, it will be essential that WaSCs are able to develop a detailed picture of the condition of the transferred assets.

Doing this will require the development of a robust database with detailed information on the condition of the assets that the individual WaSC is now responsible for, allowing potential pressure points to be highlighted. There are already some excellent systems being used by WaSCs, however any data-reliant model can only be as effective as the information that is inputted into it.

Without integrated data collection systems in place, efficient, timely and cost effective asset management will be impossible, and there is a real risk that maintenance costs will become unmanageable.

Whether its adapting internal information infrastructure or working with customers to help them understand how to properly care for their drainage, key to minimising the potential negative effect of the Private Sewage Transfer, both on the WaSCs themselves, and their customers will be developing a culture whereby thinking ahead helps to prevent drainage problems, before they actually happen.

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