Smoke testing: finding defects in drains
A smoke test means sending non-toxic smoke into a drain or sewer system. The smoke follows the pipework and comes out wherever there is a defect: a badly fitted joint, a cracked pipe, a missing trap, a leaking connection. Wherever the smoke appears, water is escaping or smells are getting in.
How it works
A generator blows the smoke into the system through a manhole or an access point, at a slight positive pressure. We then go round the building: rooms, service ducts, cellars, the foot of downpipes, outside areas. Every place the smoke comes out marks a leak. A dry or missing trap also lets smoke through, which often explains sewer smells with no water leak.
When we use it
- sewer smells in a home or a cellar;
- leaks on drains and downpipes;
- checking connections and drain ventilation.
Limits
The system has to be accessible through a manhole, a cover or an access point. If the smoke comes out somewhere that cannot be seen, under a slab for example, we follow up with a CCTV drain survey.
Frequently asked questions
Is the smoke dangerous?
No. It is non-toxic and clears quickly; you just need to air the room after the test.
Related pages
Drain and sewer leak
Drains, downpipes, connections and sewers: leaks, damp and sewer smells.
Read moreCCTV drain survey
A camera pushed into the drains: cracks, displaced joints, roots, back-falls.
Read moreFluorescein dye test
A fluorescent dye that shows where the water is coming from: drain, shower, terrace.
Read moreA leak, water ingress, an insurance claim?
Describe the situation and we'll tell you how we would proceed. 24/7 emergency service.