Surface water sewer misconnections in England and Wales: pollution sources and impacts

In urban areas served by separate sewerage consisting of separate pipe systems it is not uncommon for misconnections
to be made either accidentally or deliberately, whereby the wrong effluent is connected to the wrong
sewer. The main focus of this problem has been on in-household appliances that are wrongly connected to separate
surface water sewers, potentially leading to pollution of receiving waters and non-compliance with statutorywater
quality standards. This paper examines the available evidence to evaluate the potential scale, severity
and cost of the problem in England and Wales in comparison to that reported from investigations in the United
States. The particular difficulties associatedwith distinguishing specific sewage sources in the wastewater “cocktail”
discharged at polluted surface water outfalls are reviewed. The deficiencies of existing legislation and
enforcing compliance with respect to misconnections are also discussed and the pollution potential resulting
from domestic misconnections is explored based on sampled data.