Cross connections are an inherent part of most plumbing system. In fact, some cross connections actually have to be created in order for some plumbing systems to function properly. Backflow prevention assemblies are designed and installed with the objective of preventing the potential reversal of flow back into the potable water system. These assemblies keep you, your family, and the public's drinking water safe from backflow through cross connections.
Cross Connections are rated on a hazard scale.
Cross connections primarily fall into two categories: those that present a risk to health and those that do not. A cross connection between the potable water supply and anything that could backflow that would cause injury, sickness or even death, would be considered a high hazard cross connection.
Cross connections with fluids or substances which could backflow that would be more of a nuisance or objectionable in nature are considered a medium to low degree of hazard. Although the term medium or low hazard may be hard to apply to a particular cross connection, those that are categorized as such should never present a risk to health.