Chartered Surveyors

Old Septic Tanks and Modern-Day Restrictions

I am in the process of purchasing a new property which does not currently have mains drainage. The property has an old septic tank and upon agreeing a purchase with the current vendor, we were advised that the septic tank does meet current regulations and an inspection report would be produced in order to prove such a fact.

Historically, septic tanks often discharged into watercourses and in 2020 the law changed which meant that they can no longer disperse in such a way, and in fact, the only option for the foul water to discharge into a watercourse is to have the tank replaced with a sewage treatment plant. If a treatment plant is not installed and a septic tank Is kept, often the drainage set-up will need to be altered accordingly.

In the instance of the property I am purchasing, the septic tank report did provide confirmation that It was not breaching such legislation, however it also showcased a multitude of additional issues; the tank is under capacity for a property of this size, there are tree roots blocking the pipes (most of which belong to a tree covered by a TPO), and there is a completely collapsed chamber. The poor condition of the current tank means that a complete replacement is required. We have been weighing up our options of what to instal and how this will work – if we instal a septic tank, will this future proof us of any possible other changes in legislation, will the tree continue to damage pipework and cause an ongoing headache, and how simple is it to re-site the system entirely?

After consulting privately with another firm, we have clear options of what we can and can not do. Re-siting the system is the easiest way to proceed, as the current system can be collapsed in on itself and covered over, and the new one will be away from the protected tree. We have also decided to opt for a sewage treatment plant opposed to a septic tank or cesspit, which will mean that what we are discharging will have been treated. However, due to restrictions on location, including distance from boundaries and distance from buildings, the team want us to instal the new treatment plant in the front garden. This of course is not ideal – having man holes for the drainage in the middle of the lawn. The discussion therefore remains ongoing about what we are going to do. Perhaps we can apply for planning to remove the tree as it is causing so much damage, but morally, should we remove a tree which is surely protected for a reason?

If you are considering acquiring a property which is located a little further afield, drainage is just one of the things you will need to consider, which if you haven’t lived off-mains before, is complicated and something not everyone considers. The location of pipes and tree identification was done whilst viewing the property and we therefore had a good idea before getting this far down the line. Upon undertaking a survey, of any property, we surveyors endeavor to lift the man hole covers to inspect the visible parts of the drainage, and where properties have been extended we can advise you if this has been done over the drains, something which nowadays requires a legal build-over agreement. If you’re looking to extend to the side or rear – how will this affect the present pipework? These are all things that need to be considered when acquiring a new home.