The Environment Agency, WRC and Water UK are heavily involved in increasing awareness of the problems associated with drain misconnections.
The major concern being the effect that inadvertent connection of foul/soil water drains to surface water systems has on the environment. Surface water systems may well outfall to a watercourse and, if a misconnection has occurred, the result is contamination of streams, rivers and river basins with foul or soil waste. Apart from the aesthetic and economic impact there is the more serious problem of the affects on wildlife. The chemicals discharged from a property are toxic to plant, animal and human life. Sewage entering a watercourse, as well as being detrimental to human welfare, also increases the amount of organic matter present, which in turn increases aerobic bacterial growth resulting in the reduction of oxygen present in rivers and streams. Lack of oxygen results in a decrease of insect and aquatic life.
So basically it’s not very nice, it effects our health, it affects the economy and it kills off the lower level producers (insects, snails, worms, shrimp etc.), which in turn will impact the food chain, resulting in less smaller fish, larger fish, fish eating mammals and birds etc.
Basically if dinner is reduced there will be less diners.
Locating a misconnection is a difficult, costly process. Resolving the issue is a relatively straightforward and cheap process.
There is no simple, easily implemented, technological method of detecting foul water contamination, although the WRc are actively seeking novel, cost effective methods.
The only real method of detection, at the moment, is proactive/reactive investigation work, which is a time consuming, thus expensive, option. However there is the relatively cheap option using education and training. The NADC in conjunction with the Environment Agency and the Wrc have included misconnection location within the Certified Drain Surveyors training course. This will eventually lead to the people that are regularly involved in drainage investigation, drainage contractors, including the misconnection diagnoses during a standard condition survey.
If every drainage surveyor in the country were trained and aware of the problems associated with misconnections there would be a small armny of, in effect, free misconnection locators. In a relatively short period of time the Environment Agency would see a decrease in misconnections at hardly any cost at all.