Which fixture is required to be equipped with a backflow prevention device?

A lawn irrigation system is inherently susceptible to backflow, which can introduce contaminants from the soil or chemicals from fertilizers and pesticides into the potable water supply. Backflow prevention devices are essential for protecting drinking water by ensuring that there is no reverse flow.

The installation of such devices in irrigation systems is typically mandated by plumbing codes, as these systems can be complex and can interact with various substances that pose a risk to public health if they were to enter the drinking water supply.

While other fixtures like kitchen sinks and bathtubs may have their specific plumbing requirements, they do not typically have the same level of risk associated with backflow as lawn irrigation systems do.