Fog and Dye Testing in Sewers


Municipal Office

395 Mulock Drive P.O. Box 328 Station Main, Newmarket, Ontario
L3Y 4X7

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​​​​​​​​​​​​​​​​​The Town of Newmarket will be working with Civica Infrastructure​ to implement Fog and Dye testing in the sewers in your neighbourhood. Fog and dye testing is a safe and easy way to locate any sources of Inflow and Infiltration in the system. 

What is dye testing and why is it conducted? 

Dye testing is a method used to locate rain or groundwater entry points into the sanitary sewer system. During this process, non-toxic, biodegradable dyed water is introduced into roof leaders, driveway drains, or catch basins. After introducing the dyed water, the downstream sanitary sewer manhole is checked. Dye testing with a non-toxic, biodegradable dye is one way of determining where a pipe or structure drains to if it is not obvious by observation or on existing plans or records. By conducting dye testing, inappropriate connections can be identified. For instance, if a dye is introduced to a catch basin and the dye is then observed in the sanitary sewer downstream from that point, this would indicate that the catch basin is directly connected to the sanitary sewersystem. Dye testing is used to identify direct sources of I/I. The process consists of pouring harmless dye/water mixture into potential illegal connections. These connections form part of the storm sewer system and can consist of roof drain leaders, driveway drains, manholes, catch basins, etc. After introducing the dyed water, the ​downstream sanitary sewer manhole is checked for dyed mixture. By conducting dye testing, inappropriate connections from the storm to the sanitary systems can be identified.

How safe is the dye used?

 The dye is non-toxic, biodegradable and poses no harmful effects to humans, wildlife or the environment. The dye does not permanently stain and washes away with water. The dye is fluorescent GREEN in color. The dyed water is poured directly into the sanitary system or roof drain leaders; therefore it is unlikely that any person will come into contact with the dye. Signs will be displayed along outfalls of the storm sewer system such as rivers and creeks. Do not be alarmed if you observe a GREEN liquid entering a waterway in your area or if your waterway is GREEN during testing periods.

For more information on Fog and Dye testing, please view the Fog and Dye Testing FAQ​.

Fog and Dye Testing in Newmarket 

​Fog and dye testing has begun in Newmarket. Testing will take place in the yellow area noted below. Click the map to enlarge. 

Map of Study Area for Fog and Dy Testing in Newmarket May 2021.png

Who can I contact for more information? 

  • Tejiri Nikoro, Project Coordinator, Civica Infrastructure, 905-417-9792 ext. 2336, 
  • Nirujaan Kanagendran, Project Coordinator, Civica Infrastructure, 905-417-9792 ext. 2303, (Main Contact)