The Department for Infrastructure (DfI) is reminding the public that it is illegal to allow surface water to drain into the foul sewer network at private properties.
The requirement to separate foul and surface waters was introduced by Law in 1953. Exclusion of surface water from the foul water system not only prevents the overloading of sewer pipes during heavy rainfall that could lead to pollution incidents but also the needless expense of processing clean water at the Bellozanne treatment works.
Where public drainage has been in existence before 1953, it is permissible for both foul and surface waters to drain to 'combined' sewers. However, any subsequent development must have separated foul and surface waters, excluding the latter from the foul water system.
DfI has found that, as a result of minor developments such as extensions, conservatories and the creation of hard paved areas, surface water at some properties has been illegally draining into the foul water system. DfI is now actively visiting these areas and where drainage faults are found the Department will require under the powers of the Drainage (Jersey) Law that the situation be rectified. There is also the problem of groundwater entering the foul drainage system from poorly constructed or maintained private sewer systems and DfI again has powers under the Law to require removal.
There has seen a dramatic decrease in flows to the public pumping stations in the areas where DfI has inspected resulting in savings for DfI, in not having to pump clean water around the Island.
In recent years there has been an increase in the number of properties paving over gardens and creating parking areas, limiting where rain can go and in some cases causing it to flow onto nearby roads. Under common law the natural flow of water from higher lying properties cannot be altered or increased to the detriment of the lower land, the public roads.
In all cases it is recommended that property owners have their drains investigated by a private drainage contractor to ensure compliance with the Law. Results from such surveys can be discussed with DfI Drainage staff to ensure compliance under the Law.