Dye injection kit

A dye injection kit is a small container of concentrated coloured or fluorescent dye, usually with measuring spoons, gloves and rinse bags, used to trace flow paths through a drainage system. Engineers introduce the dye at a suspected source, such as a downpipe or basement gully, and observe at downstream chambers to confirm where the flow is going. Dye tracing is often used to confirm whether a surface water gully is wrongly connected to a foul drain, or to identify the receiving sewer for an outfall. The most common dyes are fluorescein and rhodamine, used in small quantities so as not to discolour watercourses. Discharge consents from the Environment Agency or Thames Water may apply where significant volumes are introduced or where dyes are used near watercourses.