Sewer Gas Smoke TestingServing Virginia and Maryland for Over 35 Years!
Sewer Smell in Your House? A Smoke Test Shows Where Sewer Gas Is Getting In — Without Cutting Open a Single Wall. The smell comes and goes, it moves from room to room, and the plumber has already been out twice. Smoke testing takes the guesswork out of it!
- Drain, Waste and Vent System Smoke Test
- Photos of Every Escape Point
- Marked Locations for Your Plumber
- Written Summary Included
- Follow-Up Phone Call Included
Price: $1,995Includes a smoke test of the home's drain, waste and vent system, photo documentation of each point where smoke escapes, marked locations your plumber can work from, a written summary, and a follow-up phone call to walk you through the results. One price for the home — no hourly clock, no surprises!
Does This Sound Like Your House?
Sewer gas rarely has just one way in. In most homes we test, there is more than one point where smoke escapes.
A Sewer or Rotten-Egg Smell That Comes and Goes
Often stronger in the morning, after heavy rain, when the heat or air conditioning kicks on, or after the washer or shower runs.
The Smell Is in a Bathroom, Basement or Laundry Room
These rooms hold the most drain and vent connections, and the most places for a small failure to hide.
Your Plumber Has Already Been Out
Traps were filled, the wax ring was replaced, and the smell is still there. That usually means the problem is inside a wall, ceiling or floor.
Gurgling Drains or a Smell From the Walls
Gurgling and odor from a wall or ceiling point toward the vent system rather than a fixture.
Smell something? Tell us where and when it shows up. We'll take it from there!
Let's Get Started!
Call us! We love to talk about mold!
Open 7 Days a Week:
Mon–Fri 8 AM–5 PM
Sat & Sun 9 AM–1 PM
Sewer Gas Smoke Testing: The Process
Call and Describe the Smell
Where it is, when it shows up, what has already been tried. We schedule the test — one flat price, confirmed on the phone.
We Smoke Test the Drain, Waste and Vent System
Harmless, visible smoke fills the piping from the outside cleanout. We walk the conditioned home, attic access and basement watching for where it escapes. Nothing is cut open.
Every Escape Point Is Photographed and Marked
You receive a written summary with photos and marked locations — a map your plumber can repair from, instead of searching.
Follow-Up Call and Next Steps
We walk you through the results. If smoke revealed long-term sewage moisture or bacteria in a wall or floor cavity, we outline what that means for the home and your options.
Experience. No One Has More.
Experience you can't get from a training course, and we still listen and learn on every job!
Water Damage and Mold Jobs
Water damage is the most common cause of mold, and we've worked on both sides of it for over 35 years. More than 15,000 jobs, and we still listen and learn on every one!
Happy Customers
As a former multi-state licensed general contractor, we completed more than 100,000 home service and repair jobs across every trade. That's where home systems fail, and knowing how they fail makes it much easier to find where mold is hiding and its likely sources.
Of Doctor-Referred Clients with Sick Homes
Doctors refer their patients to us. Many of those homes look spotless, yet test results point to an elevated-risk environment. If you or your doctor thinks your home is making you sick, we're the company for you.
Client Reviews
★★★★★
“Tom provided a prompt and thorough response on how to address an issue. He was honest and helpful in approaching the issue step by step, not launching into any unnecessary or upselling treatments, and explained in detail the rationale and science-based strategies around mold and moisture. He is really knowledgeable and competent. I can't thank Tom enough and would highly recommend this company.”
★★★★★
“Tom Mitchell is excellent to work with. A true expert on water damage and mold removal. Tom does a nice job analyzing the severity of the mold issue and then developing a plan to address the situation and remove mold from the home. Tom is very responsive and is dedicated to providing solutions to challenging mold/water damage problems.”
★★★★★
“I had a consult with Tom and felt very reassured by his knowledge and experience. He took great care in making sure all my questions were answered and concerns were addressed! I really appreciated his insight and would definitely recommend.”
Sewer Gas in a Home: What It Is and Why the Smell Comes and Goes
Sewer gas is the mix of gases given off by decomposing waste in drain and sewer piping — mainly hydrogen sulfide (the rotten-egg smell), methane, ammonia and carbon dioxide. A home's drain, waste and vent system is designed to carry that gas up and out above the roof while water-filled traps at each fixture keep it from coming back into the rooms. When any part of that system is cracked, separated, dry or missing, the gas takes the easier path into the house.
Why the Smell Comes and Goes
This is the question we hear most. The gas is escaping all the time; what changes is the air pressure in the home. A furnace or air handler starting up, a bathroom exhaust fan, wind over the roof vent, a change in barometric pressure before a storm, or a long shower that pushes a slug of water through the vent system — any of these can pull gas out of a wall cavity and into the room for a few minutes, then let it settle again. That is why the smell so often seems to disappear right before the plumber arrives.
Where Sewer Gas Gets In
The common escape points we find: cracked or separated vent pipes inside walls and attics (a split fitting, a nail from construction, a joint that was never glued); toilet and fixture seals (a flange that sits below the floor, a worn seal, a shower drain that was never tightened); dry or missing traps at floor drains, guest baths, utility sinks and condensate lines; vents that never made it to the roof, or were cut during a remodel; ejector pit lids, basement drains and cleanout caps; and hidden drain line breaks under a slab or behind a finished wall that have been leaking sewage water, not just gas, for a long time.
Is Sewer Gas Dangerous?
At the low levels found in most homes, sewer gas is a nuisance and a warning sign rather than an emergency. Hydrogen sulfide can be smelled at very low concentrations, well below the exposure limits set for workplaces by OSHA. The practical concern for a homeowner is less about the gas itself and more about what it points to: an opening in the drain system that has usually been letting sewage moisture and bacteria into the home as well. If a smell is sudden, strong and accompanied by dizziness or trouble breathing, leave the home and call your gas utility or 911 — that is how a natural gas leak behaves, and it is treated differently.
Sewer Gas and Hidden Moisture
Here is what most sewer-smell articles leave out. A vent pipe only carries gas, but a drain pipe carries water, and a crack or open joint on a drain line has usually been wetting the inside of a wall, floor or ceiling cavity every time that fixture is used. Sewage water is Category 3 water under the restoration standards, and the bacteria and mold that grow in a cavity fed by it are a different problem from a dry smell. A smoke test tells you which kind of problem you have. When smoke escapes from a vent, the repair is usually small. When it escapes from a drain, the smell is the symptom and the water damage behind it is the problem — the same lesson we have learned on thousands of water damaged buildings.
Why a Smoke Test Instead of Another Plumbing Visit
Plumbers are good at fixing what they can see. A sewer smell inside a wall is not something anyone can see, and the usual approach is to replace the likely suspects one at a time — a wax ring, a trap, a vent cap — and wait to find out if the smell comes back. Smoke testing reverses that. In a single visit, the smoke shows where the system is open, and the plumber can go straight to the repair. For most homes with a persistent smell, that is faster, cheaper and far less destructive than opening walls on a hunch.
Sources: OSHA, Hydrogen Sulfide — Hazards.
Sewer Gas Smoke Testing Questions, Answered
What Does It Cost?
The sewer gas smoke test is $1,995 for the home. That includes the smoke test of the drain, waste and vent system, photo documentation of each point where smoke escapes, marked locations your plumber can work from, a written summary, and a follow-up phone call to walk you through the results.
Will the Smoke Damage Anything or Leave a Smell?
No. The smoke used for plumbing tests is made for this purpose. It is non-staining, non-toxic, and clears within minutes with normal ventilation. Nothing is cut open and nothing is left behind.
Do I Need to Be Home?
Yes, for most tests. We ask you to walk with us, because you know where and when the smell shows up, and watching smoke appear in your own wall tends to settle a lot of arguments!
How Long Does the Test Take?
Most homes take two to three hours on site. Larger homes with several bathrooms or more than one plumbing stack can take longer — the price is the same.
Can the Test Be Done If the Smell Is Not Present That Day?
Yes. The smoke does not depend on the smell being active. It finds openings in the piping whether or not gas happens to be drifting into the room at that moment, which is the main advantage over sniffing around.
What Happens After the Test?
You receive a written summary with photos and marked locations. Most repairs are small once the location is known, and your plumber can work directly from the photos. If the smoke revealed long-term sewage moisture in a wall or floor cavity, we walk you through what that means for the home and the options for dealing with it.
Additional Questions
My Plumber Says It's Just a Dry Trap. Should I Still Test?
Dry traps are real and easy to rule out — run water in every drain in the home for a minute and see if the smell goes away for a few days. If it comes back, or if it was never that simple, a smoke test is the next step before anyone starts opening walls.
Is This the Same as a Sewer Camera Inspection?
No. A camera looks at the inside of the main sewer line for blockages and breaks. A smoke test looks at the drain and vent piping inside the home for openings that let gas and moisture out. They answer different questions, and a persistent smell inside the house is usually a smoke test question.
Do You Test Outside Virginia and Maryland?
We test homes across large parts of Virginia and Maryland. Check your ZIP code to find out.
How Soon Can You Come Out?
We're open 7 days a week — Mon–Fri 8 AM–5 PM, Sat & Sun 9 AM–1 PM. Call or schedule online and we'll get you on the calendar.
Smell Something? Call Us — We're Open 7 Days a Week!
Open 7 Days a Week:
Mon–Fri 8 AM–5 PM
Sat & Sun 9 AM–1 PM
Serving Virginia & Maryland · Consulting across the Continental U.S.