I am buying my first house and the search has revealed the public sewer runs through the back garden. Is this something I should worry about?

All public sewers are owned and maintained by the local water authority – in Wales, Welsh Water – and you are unable to build anything over it, such as an extension, hard-standing, summerhouse or garage, without first entering into a Building Over Sewer Agreement with Welsh Water.

These Agreements can be costly to draw up (approximately £1,000) and will specify strict conditions attached to any building works to ensure that the public sewer beneath is protected. That is why any sewers crossing rear gardens are usually situated in the bottom quarter of the garden, well away from the house so as not to interfere with any anticipated extension works.

However, there are some old properties where the sewer runs directly outside the back door and this is a major concern as it effectively makes future development, or extension work either expensive or impossible.

* Emyr Pierce is Managing Partner of Emyr Pierce Solicitors in Rhiwbina, Cardiff, Western Mail Conveyancer of the Year, specialising in Domestic and Commercial Property. Contact www.emyrpierce.co.uk or email law@emyrpierce.co.uk