Scottish Water’s Surface Water Policy Leads the Way to Innovation

We all know that both rainfall and waste water volumes are increasing. It’s obvious that our existing sewage systems are at breaking point right now and will completely fail in the near future if we don’t take steps to change how they are used right now.

Surface Water a Quick History

Up until the 1980s, foul sewage (water from toilets, baths, sinks, washing machines etc) was mixed with any surface water and transferred via a single pipe (combined sewer).

Due to environmental and flood risk management considerations, this method was changed. Foul sewage is now separated and treated via pumping stations and waste water treatment works. Surface water is drained using new surface water sewers and Sustainable Urban Drainage Systems (SUDs). After treatment, it is returned to natural waterways.

However, there are many properties that still use the pre-1980s combined sewer system.

Scottish Water are addressing this problem directly and have released new directives concerning how surface water is dealt with in the form of a policy document. There are considerable implications for all new developments, as well as renovations and projects such as home extensions.

Surface Water Policy

Scottish Water will no longer accept any new surface water connections to their combined sewers networks.

Transporting surface water using a combined sewer network means unnecessary pumping and treatment costs, which have to be passed on to the customer and do not represent value for money or provide any environmental benefit.

Problems with water quality can also arise when surface water is dealt with by combined sewers. There is more risk of sewer flooding and the associated damage to the natural water environment.

It is far more beneficial to treat surface water above ground. This contributes to good flood management and increases biodiversity in natural waterways. SUDs are made up of a sequence of surface water management processes that are designed to naturally drain and treat surface water before returning it safely to the environment.

Working with Developers

Scottish Water are now working closely with developers and regulatory bodies to promote and ensure the safe removal of surface water from our current combined sewers. This practice is supported by the Flood Risk Management Act, which places a duty on all stakeholders to manage surface water sustainably.

The principles of good surface water management can be summarised as follows:

  • manage rainfall where it falls as close to the ground as possible
  • consider rainfall as a valuable natural resource
  • remove pollutants at the earliest opportunity, rather than relying on end of pipe treatment
  • manage rainfall to protect against increased flood risk and environmental damage caused by the development
  • take account of likely impact from climate change (increased rainfall) and urban creep (extension/expansion of buildings and driveways)
  • consider multiple SUDS in series across a site (rather than using a single “end of pipe” feature, such as a pond, to serve the whole development)
  • maximise amenity and biodiversity opportunities
  • apply good placemaking principles through multifunctional use of public spaces and the public realm
  • provide a drainage system that is safe, reliable and effective over the design life of the development; Standard advice note and process guidance 3 Surface Water Policy
  • avoid pumping of surface water; and be cost-effective, taking into account both construction and long term maintenance costs and the additional environmental and social benefits afforded by the system.

The PuraTank Rainwater Harvesting Solution

In the principles of good surface water management, as stated above, we are reminded that rainfall is a valuable natural resource. In addition, the principles require us to manage rainfall to protect against increased flood risk and environmental damage.

Rainwater harvesting is a cost-effective and efficient way to both make use of rainfall as a resource and reduce the impact of surface water on the environment. The installation of a complete rainwater harvesting system allows householders to collect, treat, store and use rainwater for both potable and non-potable applications.

Above ground rainwater storage tanks are easy to install and maintain, help ensure compliance with the new regulations and also add value to new developments.

To find out more about your responsibilities as a developer or home builder, download the full policy document here: Download Policy Document