Nothing is worse than walking into your home on a cold winter day only to be greeted by a foul, sewer-like odor coming from your drains. If your sinks, bathtubs, or floor drains are giving off an unpleasant smell, winter conditions could be making the problem worse.
Cold temperatures can trap sewer gases, dry out P-traps, and clog vent pipes, leading to strong, persistent odors inside your home. Understanding why this happens and how to fix it can help prevent potential plumbing issues before they escalate into bigger problems.
Here’s what you need to know about winter drain odors and what you can do to eliminate them.
1. Dry P-Traps: The Most Common Cause of Sewer Smells
Why It Happens
Every drain in your home has a P-trap, the U-shaped pipe designed to hold water and block sewer gases from coming back up the drain. However, in winter, the air inside your home is often drier, causing standing water in unused drains to evaporate faster than normal. When a P-trap dries out, sewer gas has an open path into your home.
Signs of a Dry P-Trap
- A rotten egg or sewage smell coming from a sink, shower, or floor drain
- The odor worsens after the drain has not been used for a while
- The smell improves temporarily after running water down the drain
How to Fix It
- Run hot water down the drain for at least 30 seconds to refill the P-trap.
- Add a cup of mineral oil to slow evaporation and keep the water seal intact.
- If odors persist, a clogged or damaged P-trap may need professional attention.
2. Blocked or Frozen Vent Pipes: When Sewer Gases Get Trapped
Why It Happens
Your plumbing system has vent pipes that release sewer gases safely through the roof. In winter, these pipes can become blocked by snow, ice, or debris, preventing gases from escaping. When this happens, sewer odors build up in your plumbing and push back into your home through the drains.
Signs of a Blocked Vent Pipe
- Gurgling sounds from drains when you flush the toilet
- Slow drainage in multiple fixtures
- Foul odors coming from several drains in the house
How to Fix It
- Check for snow or ice buildup around your home’s vent pipes.
- If safe, use a broom or warm water to clear blockages from the vent opening.
- If the problem persists, a plumber can inspect and clear the vent system to restore proper airflow.
3. Grease and Food Buildup: Winter’s Hidden Plumbing Problem
Why It Happens
Many homeowners cook more hearty meals in winter, which means grease, oils, and food scraps get washed down the drain more often. Over time, this buildup can trap debris and bacteria, creating an unpleasant smell in your kitchen sink.
Signs of Grease and Food Buildup
- A rancid, musty, or sour smell coming from the kitchen drain
- Slow drainage in the sink
- Fruit flies or drain flies appearing around the sink
How to Fix It
- Flush the drain with boiling water to help break up grease.
- Pour a mixture of baking soda and vinegar down the drain, let it sit for 15 minutes, and then rinse with hot water.
- Avoid pouring grease, fats, or coffee grounds down the drain to prevent future buildup.
If multiple kitchen drains are affected, you may need professional drain clearing services to remove deep clogs.
4. Sewer Line Issues: When Odors Signal a Bigger Problem
Why It Happens
Sewer lines can crack, shift, or develop blockages over time. In winter, freezing temperatures and heavy rain can worsen existing problems, leading to leaks or gas backups that release odors into your home.
Signs of a Sewer Line Problem
- Sewer smells inside and outside your home
- Multiple drains backing up at once
- Wet or soggy patches in your yard
How to Fix It
- If you notice sewer odors near drains and slow drainage in multiple areas, call a plumber immediately to inspect your sewage line.
- Do not use chemical drain cleaners, as they can damage your pipes.
- If your sewer line is cracked or broken, a professional sewer line repair may be necessary.
When to Call a Professional Plumber
Foul odors from your drains are more than just an inconvenience—they can signal serious plumbing problems that require expert attention. If odors persist despite DIY fixes, or you suspect a sewer issue, it’s time to call Da Vinci’s Best Plumbing for professional inspection and repair.
A professional plumber can clear blocked vents, repair P-traps, and inspect your sewage system to ensure your home is safe from gas leaks and backups.
Eliminate Drain Odors for Good – Call Da Vinci’s Best Plumbing Today!
If your home has persistent sewer odors this winter, don’t wait for the problem to worsen. Call Da Vinci’s Best Plumbing at (971) 220-8685 or visit our contact page to schedule a drain inspection today!