The impact of building houses on the sewer network

By Phill Tuxford

It is estimated that Britain needs around 300,000 new homes annually to meet demand and solve the present housing crisis. So, as the Government, authorities and developers look to deliver a sustainable solution, here at Detectronic we have been discussing what impact thousands of additional properties will have on the UK’s sewer network.

Our sewer network was designed with a particular capacity in mind to meet our existing residential housing format. Any new housing development will undoubtedly add extra demand to the current sewer network. This is something that should be tackled in the pre-planning stages and it is the responsibility of the developer. If the new demands are not assessed in advance and improvements are not made to increase capacity then the sewer will simply not be adopted by the respective water company –that’s one headache any developer can do without.

Building new houses will have numerous effects on the existing sewer network. These include:

• The local sewage treatment works having to handle millions more litres of wastewater than it was originally designed to
• Changes to surface water responsibilities that are created by replacing green spaces with bricks, mortar and tons of concrete
• Upgrading pipework and connections may be required within the sewer itself in order to effectively transport wastewater
• All new UK housing developments are required to include a Sustainable Drainage Systems (SuDS)

Where do you begin to address and understand the effect of your particular housing scheme and ensure it considers all of the above? First of all, you need to understand exactly what is happening in the network and the unique hydrology of the site. A combination of flow surveys and smart network monitoring offer the ideal solution and will enable you to present robust data and a full insight to the respective water company and local authority. At Detectronic we have the flow meters and water level monitors for construction contractors to buy and conduct surveys themselves. We also have lots of experience in conducting short term flow surveys as a service.

Having this data at your fingertips is key to then implementing all of the necessary changes and enhancements that will ensure the sewer network is fit for purpose and can be adopted without any hitch by the regional water company.

It’s also vital that those who are actually constructing the houses understand how the sewer can actually be used during the building process. If the sewer is already connected to the main sewer network it can only be used for normal domestic sewage, not for pumping out surface water from footings or any other water surplus.

We’ve seen this happen all too frequently and it nearly always ends up with a blockage followed by flooding or a pollution – not what you need when you’re trying to build properties! Builders should also be aware of sand, dust or concrete entering the main sewer across the building site. Again, this can cause major issues in the wider network.

It’s a very similar story for an industrial business that may be expanding in size and production. If you generate trade effluent you need a consent license that permits a certain volume and biological composition of effluent. The sewage treatment works will allow for this and it will affect how they treat the sewage coming into the works. Any increase in that specified volume or biological composition with the launch of a new factory or production line will have a dramatic effect on the sewage treatment works causing it to surcharge or fail resulting in a costly pollution or even localised flooding.

Once again, trade effluent monitoring before the new factory is even built is the answer and can also help companies to potentially save money whilst ensuring complete compliance.

So, if you’re a developer planning to build just 100 of those 300,000 new homes, don’t get swamped by any surprises from your sewer network, implement a smart network monitoring survey today!