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1. What is the purpose of smoke testing?

The purpose of smoke testing is to find potential points of inflow and infiltration in the wastewater system. Smoke testing can also help locate the following points of groundwater or surface water intrusion into the wastewater system, any cross connections between sanitary wastewater systems and storm drains, and defective sewer connections that could allow sewer gases into a building.

During smoke testing, field crews blow air and smoke into the wastewater system in the street and monitor where smoke escapes the system. The smoke under pressure will fill the main line as well as any connections and then follow the path of any leak to the ground surface, quickly revealing the source of the problem. For instance, if smoke permeates up through a yard, it indicates breaks in the sewer line. Only enough force to overcome atmospheric pressure is required, and smoke should escape from building roof vents.

2. What is I&I?

Inflow and infiltration (I&I) are terms used to describe the ways that groundwater and stormwater enter into dedicated wastewater or sanitary sewer systems. Dedicated wastewater lines are designed to transport wastewater from sanitary fixtures inside your house or place of business to the wastewater treatment plant. Sanitary fixtures include: 

• Bathtubs
• Lavatories
• Showers
• Sinks
• Toilets

Inflow

Inflow is stormwater that enters into the sanitary wastewater system. Various sources contribute to inflow, including: 

• Downspouts
• Drains from Driveways
• Drains from Window Wells
• Groundwater/Basement Sump Pumps
• Improperly Installed or Maintained Footing/Foundation Drains
• Outdoor Basement Stairwells
• Roof Drains or Leaders

Stormwater should flow into the stormwater drainage system or allowed to soak into the ground and not cross into the wastewater pipe system.

Infiltration

Infiltration is groundwater that enters sanitary sewer systems through cracks and/or leaks in the sanitary sewer pipes. Cracks or leaks in sanitary sewer pipes or manholes may be caused by:

• Age Related Deterioration
• Damage or Root Infiltration
• Installation or Maintenance Errors
• Loose Joints
• Poor Design

3. Is the smoke harmful?

No. The "smoke" is not true smoke, but rather a mist containing a large percentage of atmospheric moisture that is highly visible at low concentrations. It will not harm your or your pet's health or leave a stain and will disappear rapidly without leaving an odor. Since any vapor can be an irritant, direct contact with the "smoke" may cause minor respiratory irritation in some people.