Expect to pay roughly $200 to $800 for a residential plumbing smoke test, based on published guides, with the high end for larger houses and tricky access. The test finds where sewer gas or water escapes from your drain, waste and vent pipes, and the price covers the diagnosis only. Our home page lists the repairs that may follow a positive test, and a visit can be requested through the quote form, which sits at the end of this page too.
What does a smoke test cost, and what does the price include?
Guides cluster between about $200 and $800 for a standard home, with a few quoting $1,000 or more for large or complicated systems. The figure normally pays for the equipment, the plumber's time and a report on where smoke escaped. Repairs get their own price after the leak turns up.
What stretches the range:
- Size. More fixtures, more stories and more roof vents mean more pipe to cover.
- Access. A clear sewer cleanout and a walkable roof keep the job short. A sealed crawlspace or a steep hillside roof does not.
- Time. A typical test takes one to three hours, but a hunt for a stubborn leak can run longer.
- Add-ons. Some plumbers pair the test with a camera look into the line, which raises the invoice and widens the answer.
Learn whether you pay a set fee or an hourly rate, and whether you receive paperwork listing every spot where smoke appeared. Compare with the general pricing on the plumber inspection cost page.
How does a smoke test work?
The plumber plugs the main sewer cleanout so smoke cannot simply drift off toward the city line, then blows dense, non-toxic smoke into the drain and vent system with a small machine. Walking the house and roof, they watch for wisps. Smoke leaking from any spot is a path sewer gas could take.
Where smoke most often shows up:
- At a cracked or loose vent pipe poking through the roofline or sitting in the attic.
- At a dry fixture trap, where the water seal has evaporated.
- At a joint inside a wall, which shows as a haze or a smell of smoke.
- In the yard, above a broken buried sewer line.
Smoke is not the same as fire. Tell your household and neighbors beforehand, because a drifting plume can look alarming, and let the plumber warn the fire department if that is their practice. The smoke is described as safe for people and pets, though people with breathing conditions may want to step outside.
Why would I need one in the first place?
The typical trigger is an odor from the drains that keeps coming back despite the obvious fixes: filled traps, a cleaned drain, a new wax ring. Other reasons include suspected root damage, a house with a history of drainage trouble, a buyer's inspection, or a plan to confirm that a repair has sealed the line.
Check the cheap causes first. A floor drain or a guest bathroom that has not been used in months can dry out, and pouring a pitcher of water down it restores the seal for nothing. If the odor persists with every trap full, a test makes sense. Two other pages walk through the easy fixes: clearing a sewer smell at home and hiring help for a sewer odor.
Is sewer gas dangerous, and who do I call if I smell gas that is not sewage?
Sewer gas has a rotten-egg smell, and in poorly ventilated spaces it can irritate and cause headaches, so ventilate and find the source. Natural gas is different, and it is the one that can explode. Whenever gas is the suspect, walk out and ring your gas utility from the street, ahead of everything else.
In Long Beach and Signal Hill the gas utility is Long Beach Energy Resources, and its gas emergency line is 562-570-2140. Much of the surrounding region is served by SoCalGas instead (1-800-427-2200). Any immediate danger calls for 911. The smell of rotten eggs is deliberate: utilities add an odorant to natural gas so you notice a leak, which means a rotten-egg smell can be either one, and a smoke test is the wrong first step.
Smoke, camera or dye: which test answers my question?
Each tool answers a different question. Smoke finds leaks in the vent system and gaps where gas escapes. A camera shows the inside of a buried sewer line, including cracks, roots and sags. Dye shows whether water from a fixture reaches the sewer. Your problem decides the test.
A leak with sewage in the yard or repeated clogs usually points to a camera inspection. An odor with no clog points to smoke. Many plumbers do both when the story is murky. Older Long Beach homes near the harbor, where buried clay or cast iron pipe laid before 1960 is still in service, are good candidates for the camera, since those materials crack and corrode.
For comparison, leak detection cost covers the tools used for pressurized water lines, which a smoke test does not look at.
Does Long Beach require a permit for the repair?
A smoke test by itself changes no piping and needs no permit. Repairs may. The City of Long Beach requires a plumbing permit to install, alter or repair drainage piping, and the plumber should explain which repairs trigger one. Owner-occupants may pull permits for their own work, but most sewer repairs go to a contractor.
If the test shows a broken line beneath a slab, expect an estimate from the plumber with the method and permit costs spelled out. Our overall plumber cost guide helps you judge whether a quote looks reasonable.
Common questions
Will this take up my whole afternoon?
Allow one to three hours for an average house, with extra time if the leak is hard to find. Everything depends on reaching the cleanout, the roof vents and the fixtures. Big homes, upper floors and blocked access run longer, and the estimate comes with the quote.
Which questions come before booking one?
Learn exactly what the fee buys and whether you receive a report. Check how repairs would be priced should smoke appear. Run the contractor's license number past the state board, and settle the figure on paper before equipment comes out of the truck.
Should someone be present while the smoke runs?
Yes. The plumber needs every room and the cleanout reachable, and watching where smoke escapes is the best way to understand the result. Give neighbors a heads-up, and keep pets and anyone with a breathing condition elsewhere while smoke fills the pipes.
Will the test cure the odor?
No. It only locates the escape; repairs cure it. The answer can be cheap, like a dry trap or a split vent cap, or it can be a buried line repair costing far more. Treat the test as the price of knowing which one you have.
References
- Wikipedia, Smoke testing (mechanical)
- City of Long Beach, plumbing permit requirements
- Published sewer smoke test cost guides from several plumbing sites, checked November 2026
Updated