Watertight drainage systems

Any drain can leak. The impact of leaks can be severe, ranging from health and environmental issues, through additional costs in water sourcing and treatment, to structural damage. Leaks can sometimes be catastrophic, whilst repairs are always costly and sometimes very disruptive. There are an estimated 2.5 million km of public sewers across the EU (plus all the private sewers) so the cumulative effect of leakage is dramatic. And since drains may often be empty, damage can build up unobserved.

Leaks can undermine roads and even buildings – several recent spectacular ‘sinkholes’  have been blamed in part on leakage from broken drains creating voids, particularly where gypsum was the underlying rock.

Flexible (plastic) drainage pipes tend to deform rather than break under pressure, and many studies worldwide have found them to have lower defect rates than rigid pipes. The choice of material is just one factor, though. Whatever the material, watertight drainage systems need good design and planning, installation, testing, inspection and maintenance. 


Sustainable drainage systems

Good design can prevent many problems, and reduce the cost of any remedial work. Connections between pipes are a common cause of leaks, and many faults are caused by poor installation and supervision. Establishing best-practice installation procedures and ensuring they are conscientiously followed will repay the extra labour costs many times over. Manufacturer recommendations for trenches and bedding materials need to be followed rigorously, for example. While completed pipe runs are tested for watertightness, remedial action at this stage is expensive. Here especially prevention is much, much better than cure.

‘Problems with drains’ appear to be part of the human condition. Serious pollution events can come from either infiltration or exfiltration, depending on the pipe contents. But leakages and failures and their consequential damage can be drastically reduced. Sustainable drainage systems benefit our health, our environment, and also our balance sheets.

Read more on this subject in our article “Towards leak-free drainage systems”, or download the white paper “Watertightness of stormwater and foulwater systems” .