More than 40% of Phoenix’s water and sewer pipelines were installed between 1950 and 1980. These pipes have a 75-year life expectancy, meaning a massive wave of infrastructure is starting to age out starting this year. The City of Phoenix has forecasted a need for $5.4 billion in repairs and replacements for the sewer system to prevent failures and odors.
As public infrastructure ages, your sewer lines and plumbing systems are feeling the strain. If your house smells like sewage, your pipes may be sending you a message. While it could be a simple fix because the water in your P-trap has evaporated, it could mean problems under the slab.
In this guide, we’ll cover:
- Why does my house smell like sewage?
- Warning signs you shouldn’t ignore
- Sewage smell outside your house
- How to get rid of sewage smell in your house
- When to call emergency plumbing in Phoenix
- Choosing the right plumber in Phoenix, AZ for sewage smells
Plus, we’ll answer some of the most frequently asked questions about why your house smells like sewage.
Why Does My House Smell Like Sewage All of a Sudden?
When sewer odors appear suddenly, something in your plumbing system has changed. Here are some of the most common causes.
Dry P-Traps
Hopefully, this is the reason because it’s the easiest to fix.
Underneath your sink, shower, tub, or drain is a P-trap. It’s designed to hold a bit of water to form a seal that prevents sewer gas from sneaking into your home. If it dries out, there’s nothing blocking the odor from finding its way into your house.
In extreme Arizona heat, especially during summer, that water seal can evaporate in as little as one to two weeks, so you’re more likely to find this happening in any guest bathrooms, pool houses, or vacation homes.
Pro Tip: Sometimes all it takes is to run the tap for a few minutes or pour water down your drain to refill the P-trap.
Vent Stack Blockage
Plumbing systems have roof vents that release sewer gas safely outside your home. Birds like to build nests there, and debris can get stuck, especially during monsoon season where the winds can push debris into your vent. This restricts the airflow, preventing the gas from escaping, so it backs up and produces that sewage smell in your house.
Pro Tip: If the smell changes with the weather or appears after storms, there may be an issue with your venting, and you’ll need to clear it.
Main Sewer Line Restriction
If your house smells like sewage and you have multiple drains that are slow to empty or they gurgle at the same time, a partial blockage in the main sewer line may be trapping gases inside the system. When air cannot move properly through pipes, it escapes wherever it can.
Pro Tip: This can be a clog, crack, or other problem in your main sewer line, which runs underneath your slab. Call a plumber for a sewage smell to diagnose the issue and recommend a solution.
Failing Toilet Wax Ring
Toilets have a wax ring that seals off the bottom to prevent sewer gas from escaping. They do wear out over time, especially in the Phoenix area if you have a slab-built home where minor shifts in your foundation are common.
Pro Tip: If the small is strongest near the base of your toilet, the wax ring may have deteriorated or shifted. Call a plumber and have them replace the wax ring and reseat your toilet.
Sewage Smell in Your House: Warning Signs You Shouldn’t Ignore
Sewer gas can include a long list of compounts, including:
- Hydrogen sulfide (H₂S)
- Methane (CH₄)
- Ammonia (NH₃)
- Carbon dioxide (CO₂)
- Sulfur dioxide (SO₂)
- Nitrogen oxides (NOₓ)
- Carbon monoxide (CO)
- Chlorine (Cl₂)
- Volatile organic compounds (VOCs)
- Hydrogen cyanide (HCN)
- Phosphine (PH₃)
- Indole and skatole
In high concentrations, some of these gases can be dangerous. However, you’ll typically experience your house smells like sewage well before there’s a sewer gas buildup that’s dangerous. But continued exposure can cause health concerns, so watch out for any of these warning signs:
- Multiple drains producing odor
- Gurgling sounds from sinks or tubs
- Slow draining combined with smell
- Odor gets stronger after your washing machine discharges
- Smell near floor drains in a laundry room or garage
Sewage Smell Outside Your House
When a sewage smell outside your house shows up, you might assume it’s part of the municipal system and the city needs to fix it. That does happen from time to time, but in many cases, the smell comes from the lateral sewer line that runs from your home to the city connection. That’s your responsibility, not the city’s.
Outdoor sewer smells are often more serious because they can be symptoms of pipe deterioration, soil saturation, or venting failures beneath the slab. Here’s how to interpret what you’re smelling.
Odor Near the Sewer Cleanout Cap
The sewer clean-out is one of the first places to investigate. In Phoenix, look for a three to four inch round white or black PVC cap sticking slightly above ground level. Sometimes you’ll find them just underneath landscaping or partially covered by gravel or grass. The sewer cleanout cap will most likely be located:
- In your front yard near the sidewalk
- Along your side yard close to the foundation
- Near your driveway
- In your backyard (older properties)
If you notice a sewage smell outside the house and the odor is strongest near this cap, you might be looking at:
- A loose or cracked clean-out cap
- Pressure buildup in the sewer lateral line
- A partial blockage causing gas to escape
- A deteriorating underground pipe joint
Don’t remove the cap. There’s often pressure behind it, and it could discharge wastewater. Instead, call a plumber for sewage smells in Phoenix.
Pro Tip: If the smell gets worse near the cleanout cap after you run the water inside or during monsoon storms, you likely have a restricted sewer flow.
Persistent Yard Odor Smelly Soil
If you detect a sewage smell outside your house, but not directly at the clean-out, walk the yard slowly to see if you can find where the smell is the strongest. This is typically caused by:
- A cracked sewer lateral pipe
- A pipe joint separation
- Root intrusion causing leakage
- Soil saturation from slow seepage
Older sewer laterals, especially those installed decades ago, are increasingly vulnerable. Phoenix soil conditions, combined with aging pipes, can allow small leaks to go unnoticed for months before odor becomes obvious.
Pro Tip: Wastewater that’s leaking is nutrient-rich and may cause the grass to grow much faster or get greener in certain areas. You may see this even before you start to smell it. You may also notice parts of your yard remain damp even during dry weather.
Strong Smell After Heavy Rain or Monsoon
Monsoon season adds another layer of pressure to sewer systems. When there are heavy rains, the flow through municipal sewer lines increases. If your sewer pipe that connects to the city sewer lines has a problem, the added pressure can force sewer gases back toward your property.
Pro Tip: While the odor may be temporary after heavy rains or when humidity is high, you’ll want to get it checked out because there’s a good chance it’s a structural issue.
Odor Near Foundation Walls
If you notice a sewage smell outside your house near the foundation, your sewer line under your slab might be damaged. Even a small crack under the slab can allow gas to escape.
Warning signs include:
- Odors strongest near one corner of the home
- Faint smell detectable only outside
- No obvious drain backups
Pro Tip: You might notice this first outside close to your bathroom or laundry areas. A highly trained plumber in Phoenix, AZ can do a sewer camera inspection to check for blockage or cracks.
How Do I Find Where the Sewage Smell Is Coming From?
Here is a quick snapshot of the symptoms, likely causes, and how severe your sewer smells are.
| Symptom | Likely Cause | Severity |
| Odor disappears after running water | Dry P-trap | Low |
| Odor + slow drains | Partial main line blockage | Moderate |
| Odor + backups | Sewer line failure | High |
| Odor only with hot water | Water heater issue | Low-Moderate |
| Odor outdoors near clean-out | Lateral line issue | Moderate-High |
How To Get Rid of Sewage Smell in Your House
When your house smells like sewage, try these steps first:
- Run water in all drains to restore P-traps.
- Flush all of your toilets.
- Check your sink overflow hole for buildup.
- Check the toilet base for movement or moisture.
- Inspect the clean-out cap outside.
- Pour water into garage or laundry floor drains.
If odors last more than 24–48 hours or the sewage smell returns quickly after you refill your drains, call a plumber for service.
Drain Cleaning Solutions for Phoenix Homes
If you have a clogged drain, start by using an enzyme-based drain cleaner. Avoid harsher chemical cleaners because they can damage your pipes.
If this doesn’t work, a plumber can try several approaches.
Mechanical Clog Busting
Using commercial-grade augers or drain machines, a technician can remove clogs like hair or hardened soap buildup. This approach is effective when the blockage is confined to a specific branch line or fixture. However, if the odor is affecting multiple drains or returning frequently, there’s more going on.
Hydro Jetting
Hydro jetting is often recommended for Phoenix homes experiencing recurring buildup. This process uses high-pressure water to scour the interior walls of pipes, removing grease, scale, biofilm, and mineral deposits that accumulate over time.
The hard water in the Valley makes buildup common, trapping gunk in your pipes, which can make your house smell like sewage. Hydro jetting clears it up and gets rid of the buildup.
Sewer Camera Inspection
If symptoms indicate a potential problem under the slab or in your yard, a sewer camera is inserted into the sewer line to check for cracks or problems before having to dig up your yard or cut into your slab. This allows plumbers in Phoenix, AZ to identify cracks, corrosion, root problems, or other damaged sections.
In cases where the sewer lateral line is deteriorating, repair or partial replacement may be required. Spot repairs can often replace sections where pipes are damaged. However, in some cases, you may need pipe replacements. Another option might be trenchless lining, where you insert a resin liner that cures inside the pipe.
Vent Stack Inspection
Professional vent stack inspection can check for blocked or damaged vent pipes and clear any obstructions to restore proper airflow and get rid of that sewage smell in your house.
When To Call Emergency Plumbing in Phoenix
Sewer gas smells might be minor, but there are times when you need emergency plumbing in Phoenix. Call for service if:
- Sewage is backing up into tubs or showers.
- Multiple drains stop working simultaneously.
- Odor becomes overpowering throughout the home.
- Standing wastewater is visible.
- You experience nausea or dizziness along with strong odor.
Routine odors can often be addressed with scheduled service. Backups and widespread failure require urgent attention.
Choosing the Right Plumber in Phoenix, AZ for Sewage Smells
For more than 35 years, George Brazil Plumbing & Electrical has served the Phoenix metro area, earning 2,800+ five-star reviews and maintaining a BBB A+ rating. When you need a plumber in Phoenix AZ you can trust, call George Brazil.
FAQs
How do I get rid of a sewage smell in my house fast?
Start by running water in every drain to refill P-traps. If the odor persists after that, professional inspection is the fastest way to resolve the root cause.
Should I call a plumber for a sewage smell?
If the smell continues despite basic troubleshooting or affects multiple drains, calling a plumber to fix the problem.
Can a clogged drain cause a sewage smell throughout the whole house?
A partial main sewer line blockage can trap gases and make your house smell like sewage.
Why does my bathroom smell like sewage even after cleaning?
Cleaning removes what’s on the surface, but it won’t fix dry traps, vent problems, or failing sewer lines.
If your house smells like sewage and basic steps have not solved it, scheduling an inspection with George Brazil Plumbing & Electrical ensures the problem is diagnosed correctly and resolved before it becomes a larger repair. Schedule service today. If you need emergency plumbing in Phoenix, we’re available 24/7.