Gas Leak or Sewer Smell? How to Tell the Difference and React Quickly

08-30-2025

A mysterious smell in your home can be unsettling. But some smells are more than just a nuisance—they are a clear warning sign. At Judd's Plumbing, we know that confusing a natural gas leak for a sewer smell (or vice versa) can have serious consequences. Your safety is our top priority. Use this guide to identify the smell and take the correct, immediate action.

Part 1: The Gas Leak (An IMMEDIATE Emergency)

What It Smells Like:

Natural gas is naturally odorless. Utility companies add a chemical called mercaptan to give it a distinct, sulfur-like smell, often described as:

• Rotten eggs
• Sulfur
• A skunk-like odor

Other Signs of a Gas Leak:

• A hissing or whistling sound near a gas line or appliance.
• Bubbles in standing water or puddles outside.
• Dust or dirt blowing from a hole in the ground.
• Dead or discolored vegetation in an otherwise healthy area.

WHAT TO DO IMMEDIATELY (Do NOT use your phone inside!):

1. EVACUATE everyone from the house immediately. Do not stop to gather belongings.
2. DO NOT create a spark. This means:
   • Do not flip light switches on or off.
   • Do not use any electrical appliances or phones.
   • Do not light matches or candles.
   • Do not start your car if it's in an attached garage.
3. Go to a safe location far away from the house.
4. CALL 911 and your gas company from your cell phone outside or from a neighbor's house.
5. Only after the gas company has cleared the property, call Judd's Plumbing at 623-304-5833 to repair the source of the leak.

Part 2: The Sewer Smell (A Urgent Plumbing Issue)

What It Smells Like:

Sewer gas has a more complex, foul odor:

• Rotten eggs (from hydrogen sulfide) but often mixed with...
• Decaying organic matter
• Methane
• A musty, foul smell that is persistent.

Common Causes of Sewer Smell in Your Home:

• Dried-Out P-Traps: The U-shaped pipe under sinks, showers, and floor drains holds water to block sewer gas. If a drain isn't used often (like in a guest bathroom or floor drain), the water evaporates.
• Blocked or Damaged Plumbing Vents: Vents on your roof allow sewer gas to escape outside. If they're blocked, the gas can be forced back into your home.
• Damaged Sewer Lines: A crack or break in your home's main sewer line can allow gas to seep into your yard or basement.
• Loose or Broken Toilet Seals: The wax ring sealing your toilet to the floor can fail, letting gas escape into the bathroom.

WHAT TO DO:

1. Identify the Source: Try to pinpoint which room or drain the smell is strongest in.
2. Run Water in All Drains: If you have infrequently used drains, run water for 30 seconds to refill the P-traps. This is often the simplest fix.
3. Check for Missing Cleanout Plugs: Ensure the main sewer cleanout plug is secure.
4. Call a Professional Plumber: If the smell persists, you likely have a more serious issue like a blocked vent or broken sewer line.

Call Judd's Plumbing at 623-304-5833. Our technicians can use camera inspections to locate the exact source of the sewer odor and fix it permanently.

Quick-Reference Chart: What's That Smell?

| Symptom | Gas Leak | Sewer Odor | | ----- | ----- | ----- | | Primary Smell | Rotten eggs / skunk | Rotten eggs + decay / musty | | Sound | Hissing or whistling | Gurgling drains | | Where | Near gas appliances or lines | Near drains, toilets, or basement | | Immediate Action | EVACUATE. Call 911 & gas co. from outside. | Investigate, run water in drains. | | Who to Call | Gas Company & 911 (then Judd's for repair) | Judd's Plumbing (623-304-5833) |

When in Doubt, Err on the Side of Caution

If you cannot immediately identify the smell as a harmless sewer issue, treat it as a gas leak. Your safety is more important than a potential false alarm.

Don't Ignore Foul Odors—Protect Your Home and Family

Whether it's a dangerous gas leak or a sign of failing plumbing, strange smells demand attention. For all plumbing-related odors, the team at Judd's Plumbing is here to provide fast, reliable, and safe solutions.

For 24/7 Emergency Plumbing Service:
📞 Call 623-304-5833
🌐 Visit https://juddsplumbingaz.com