Savills : Off grid drainage – how to avoid your house sale getting stuck in the pipeline

If you're thinking of selling your home then finding out what type of drainage system the property has may not necessarily be top of your list of priorities.

But for anyone living off grid it is vitally important. Put simply, Environment Agency (EA) rules state that if homeowners have a septic tank that discharges to a water course, stream or ditch, then it needs to be upgraded to a proper sewage treatment system. Failure to do so is an offence and could mean you risk prosecution or a significant fine.

However, many people remain unaware of how the drainage system in their home works -potentially causing a delay to the sales process. Often the first time homeowners realise there's a problem is when the buyer's survey is conducted.

Having all of the information to hand early on can help iron out any issues - with any improvements built in as a condition of sale.

As an initial step homeowners need to identify the type of drainage system their property has and where it is discharging. However, this needn't be as onerous as it sounds.

Contact your local drainage engineer (the person who usually empties the tank or carries out regular maintenance) to see if a certificate of compliance can be issued. If not then there may be a need for further on-site investigations. This could take the form of CCTV surveys of underground pipe work or - sometimes - excavations where previous investigations have been unable to provide enough information.

Once known, homeowners then need to ensure the system complies with the General Binding Rules (GBR) 2015 and that it is properly maintained in line with the manufacturer's guidance.

If the system is compliant with GBR then only ongoing maintenance is required. If the system requires replacement or adapting, help must be sought from a specialist drainage contractor or engineer to ensure compliance and suitability for local ground conditions. In some cases planning consent may also be required, while for those who are unable to upgrade their systems due to site limitations then a permit must be applied for from the EA.