Sewer smoke testing is a field diagnostic method used to identify defects, illegal connections, and sources of inflow in sanitary sewer collection systems. CIVICA Infrastructure Inc. provides smoke test services to municipalities, conservation authorities, and engineering consultancies across Ontario, supporting Inflow & Infiltration (I/I) reduction programs, regulatory compliance, and capacity management investigations.
A smoke test for sewer systems involves introducing non-toxic, pressurised smoke into the sanitary sewer through manholes or cleanouts. The smoke travels through the pipe network and exits through any openings: defective pipe joints, cross-connections, broken laterals, or improperly sealed service entries. Visible smoke plumes at ground level indicate defects that allow stormwater or groundwater entry, or in some cases, sanitary sewage escape.
Sewer smoke testing is typically deployed during I/I investigation projects when municipalities need to locate specific sources of excess flow. The method is particularly effective in identifying:
Smoke testing does not require flow isolation or system shutdown. It can be conducted in active systems and is often scheduled during dry-weather periods to eliminate interference from wet-weather flows.
CIVICA’s field technicians prepare the test area by notifying property owners and posting signage to explain that visible smoke is part of a planned infrastructure inspection. Advance notification reduces public concern and ensures cooperation.
The crew then isolates the test section using pneumatic plugs or natural system boundaries. A smoke blower unit injects non-toxic theatrical smoke into the sewer through an accessible manhole. Pressure is maintained for a minimum of 10 to 15 minutes while observers walk the test area, recording all smoke emissions with GPS coordinates, photographs, and written descriptions.
Smoke that appears on the surface is traced back to its source — often a specific property lateral, catch basin, or manhole. These locations are documented and compiled into a defect inventory for prioritisation and follow-up CCTV inspection or repair.
The smoke used in sanitary sewer testing is non-toxic, non-staining, and dissipates quickly. It meets municipal health and safety standards and poses no risk to occupants if it enters buildings through plumbing traps that have lost their water seal. However, if smoke enters a home, it typically indicates a plumbing defect, often a dry trap or improperly vented fixture, that should be corrected by the property owner.
Advance communication with residents and coordination with municipal by-law or public works departments is standard practice. CIVICA manages stakeholder notification, permitting, and compliance with local protocols as part of the service.
Sewer smoke testing is most effective when integrated with other diagnostic tools. It is often used alongside flow monitoring and wet-weather inspections to validate suspected defect areas identified through hydraulic analysis or capacity modelling.
For example, if hydraulic modelling suggests elevated I/I in a specific catchment, smoke testing can pinpoint the exact sources contributing to the problem. Once defects are located, CCTV inspection provides internal condition documentation to inform repair scoping and cost estimation.
This layered approach, combining field observation, flow data, and internal condition , produces more accurate and defensible infrastructure investment decisions.
CIVICA delivers a smoke test report that includes:
The report supports wastewater system capacity planning, capital project scoping, and regulatory submissions under provincial Inflow & Infiltration management programs.
Get in touch with us today to learn more about our sewer smoke testing services in Toronto and the GTA.
CIVICA’s field services division operates across Ontario with trained crews, calibrated equipment, and a track record of accurate defect identification. The company’s vertically integrated model means smoke test findings can be immediately incorporated into broader consulting and modelling work, streamlining project timelines and reducing coordination overhead.
As a specialist in stormwater and wastewater collection system management, CIVICA understands how smoke test results fit into larger I/I reduction strategies, regulatory compliance programs, and capital planning frameworks. The firm’s technical staff interpret field findings in the context of hydraulic performance, not just as isolated defects.
For municipalities, conservation authorities, and consulting engineers managing sanitary sewer performance, a smoke test sewer investigation provides cost-effective source identification that supports targeted, evidence-based infrastructure improvements.
