It depends on what you need. To test a building for sewer gas in an emergency, call 911. For a possible natural gas leak, call Southwest Gas. A plumber finds and fixes the leak path. An industrial hygienist measures the air and writes a report. Workers can also file a complaint with ADOSH.
Who to call, by situation
Start with the row that matches what's happening right now. Safety calls come before testing calls.
| Your situation | Call | What they do |
|---|---|---|
| Strong smell, anyone dizzy, sick or with stinging eyes | 911 | Clear the building and check the air. Wisconsin says to evacuate and call the fire department if gas may be concentrated in an enclosed space. |
| Rotten-egg smell near gas appliances or the meter | 911 and Southwest Gas, 877-860-6020 | Check for a natural gas leak. Southwest Gas says to call whether or not you have gas service. |
| Smell from a street manhole or the public sewer | Your city's water or sewer department (Phoenix: 602-262-6251 on weekdays, or 602-261-8000 for a sewer emergency such as an overflow) | Check city lines and manholes. |
| Recurring smell in a home, suite or restroom | A licensed plumber | Find the leak path (trap, vent, seal, cracked line) and fix it. |
| Need measured levels, a written report or proof for a lease dispute or insurer | An industrial hygienist, ideally a Certified Industrial Hygienist (CIH) | Sample the air and document exposure. |
| Employees worried about exposure at work | The employer first; anyone can also file with ADOSH | ADOSH can inspect or require the employer to respond. |
What each one does
### The fire department: when it's an emergency
If the smell is strong or people have symptoms, don't shop around for a tester. Call 911. Wisconsin's health department tells people to evacuate and call the fire department when they believe sewer gas is concentrated in an enclosed space, and to avoid anything that could make a spark. Their job is making the space safe, not finding the plumbing defect, so plan on a plumber afterward. See when to evacuate for a sewer smell.
### Southwest Gas: when it could be natural gas
Natural gas and sewer gas can smell alike, because Southwest Gas adds mercaptan, which smells like sulfur or rotten eggs, to otherwise odorless natural gas. If the smell is near a stove, water heater, boiler or meter, leave first, then call 911 and Southwest Gas at 877-860-6020 from a safe place. How to tell a gas leak from sewer gas covers the clues.
### A plumber: finding and fixing the source
Most sewer smells are a plumbing leak, not an air quality mystery. Wisconsin's advice is to follow the odor, refill floor drains, check the roof vent for debris, and hire a plumber when the source is behind a wall. A plumber's job is to find the path: a dry trap, a failed toilet seal, a loose cleanout cap, a blocked or broken vent, a leaking ejector pit cover or a cracked drain line. When the path isn't obvious, a smoke test finds it: smoke is pushed into the drain and vent system and shows up wherever gas can escape. HQ runs these tests with professional liquid-smoke equipment that forces the smoke through the vent system under air pressure. Meters can help too, but the fix is what ends the smell. See why a bathroom drain smells like sewer and sewer gas smell in a commercial building.
### An industrial hygienist: measured air and a report
When you need numbers on paper, bring in an industrial hygienist. They're the professionals who assess workplace air and exposure. The Certified Industrial Hygienist (CIH) credential is issued by the American Board of Industrial Hygiene, now called the Board for Global EHS Credentialing. OSHA says air testing for hydrogen sulfide must be done by a qualified person using the right equipment, such as an electronic hydrogen sulfide meter. A hygienist's report is useful when:
- A tenant, employee or insurer wants documented levels.
- You need to show a space is safe for staff to go back in after repairs.
- Symptoms continue after the plumbing has been fixed.
Their report tells you how much gas is present. It won't fix the source, so plan on a plumber too. For the limits a hygienist compares against, see OSHA's limits for hydrogen sulfide.
### ADOSH: when it's a workplace issue
Arizona runs its own workplace safety program, the Arizona Division of Occupational Safety and Health (ADOSH), under the Industrial Commission of Arizona. ADOSH says anyone can file a complaint about unsafe working conditions, and a complainant may stay anonymous. A valid complaint may lead to an on-site inspection or a letter asking the employer to respond with what it fixed.
Employers have a second option. ADOSH offers consultation visits scheduled in advance, and it says a consultation ends in a report to the employer with no citations or penalties. You can reach ADOSH at (602) 542-5795 or file through the Industrial Commission of Arizona website. That's a reasonable route for a business owner who wants a second set of eyes on a pump room or ejector pit before it becomes a complaint.
Questions to ask before you hire anyone
Whoever you call, a few questions sort out whether they'll solve your actual problem:
- "Will you find where the gas is getting in, or only measure it?" A reading without a source leaves you where you started.
- "Which gases does your meter read, and when was it last checked?" You want hydrogen sulfide in ppm at minimum. OSHA passes along the industry advice to bump test or calibration check portable monitors before each day's use.
- "Will you read the air at floor level and near drains and pits?" Hydrogen sulfide is heavier than air, so a reading at eye height can miss it.
- "What will I get in writing?" For a lease dispute, an insurance claim or a worried staff, a dated report with readings, locations and the instrument used carries more weight than a verbal all-clear.
- "Is anyone going into a pit, vault or manhole?" If yes, OSHA's rule is that a qualified person tests the air first, and that person should explain how they'll do it.
Most sewer smell jobs need two of these people, not one: somebody to fix the plumbing, and sometimes somebody to document the air before and after.
Can I test it myself?
You can buy a meter, but know its limits before you trust it. A cheap sensor that reads the wrong gas can give you false comfort in exactly the room that needs attention. A combustible gas sniffer reads methane, not the rotten-egg gas, and any meter needs regular bump tests to be trusted. See do sewer gas detectors work and do I need a hydrogen sulfide detector. Never open or climb into a sewage pit, vault or manhole to take a reading.
HQ Plumbing is licensed and insured, offers 24/7 emergency service and gives free estimates with upfront pricing. We smoke test and fix the plumbing side of a sewer smell in homes and commercial buildings across the Valley.