Why Your Shower Drain Smells Worse After a Storm

You survived the storm. The trees stayed upright, the basement stayed (mostly) dry, and the power even stayed on. But now? You walk into your bathroom and—bam—that unmistakable sewer stench is wafting up from your shower drain.

Not exactly the fresh, clean post-storm vibe you were going for.

At All Pro Heating, Air & Plumbing, we get this call all the time from Central Indiana homeowners. And the good news? That nasty smell usually has a fix. The bad news? Ignoring it could lead to bigger, messier problems.

First, What’s That Smell?

If your shower drain starts smelling like rotten eggs, sewage, or swamp water, it’s almost always related to gas or bacteria creeping up from your pipes. After a storm, the extra water and pressure in the system can stir up the gunk that’s been sitting in your drains or pipes, bringing foul odors with it.

What you’re smelling could be:

• Hydrogen sulfide gas (aka: sewer gas)

• Mold or mildew from excess moisture

• Bacterial growth in your P-trap

• Backed-up sewer or drain lines

And yes—it can get worse after a heavy rain or storm.

How Storms Stir Up Shower Drain Odors

So why does bad weather make your bathroom smell like a science experiment gone wrong?

1. Pressure Changes Force Gases Upward

Storm systems change air pressure both inside and outside your plumbing. If there are weak seals, broken vents, or cracks in your lines, this shift can force sewer gases back through your drains and into your home. Not ideal.

2. Backed-Up Sewer Lines

Excess water in the city’s main sewer lines can cause slow drains or minor backflow in your system. Even if water doesn’t rise into your shower, the increased pressure can push gasses up and out of the drain.

3. Overwhelmed Drainage Systems

If your home’s drains or sump pump system are overwhelmed during a storm, it creates the perfect environment for bacteria and sludge buildup—which, surprise, can smell terrible.

4. Evaporated Water Seals

In some rarely used showers or floor drains, the water in the P-trap (the U-shaped pipe that blocks sewer gases) can evaporate. When that barrier is gone, odors have a straight shot into your home. After a storm, high humidity and shifting air pressure can accelerate this issue.

What Central Indiana Homeowners Need to Know

Here in the middle of the state, we’re no strangers to wild weather. Between heavy spring rains, summer thunderstorms, and even surprise winter ice storms, our homes take a beating from the elements all year round.

Older homes with aging plumbing systems are especially vulnerable. Many homes built decades ago weren't designed with modern drainage or venting needs in mind. Combine that with mature trees, shifting soil, and old clay sewer lines, and you've got the perfect conditions for weird post-storm smells.

Even newer homes aren’t immune, especially if the drainage or venting system wasn’t installed properly, or if construction debris is lurking in your lines.

What You Can Do to Get Ahead of It

The good news? A smelly shower drain isn’t always a disaster. It’s just a signal that something needs attention. Here’s what you can do to stay ahead of it:

Run Water in Unused Drains

If you’ve got a guest bathroom or basement shower that rarely sees action, run the water for 30 seconds every few weeks. Keeping the P-trap full is one of the easiest ways to block sewer gases.

Check for Obvious Blockages

Hair, soap scum, and grime can build up in your shower drain and act like a bacteria magnet—especially after a storm stirs everything up. Remove the drain cover and clean out anything visible (gloves are highly recommended).

Ventilate Your Bathroom

Use exhaust fans during and after storms to keep air flowing. This helps regulate pressure and move odor out of the room more quickly.

Know When to Call All Pro

If the smell lingers, keeps coming back, or is paired with slow drains, gurgling sounds, or water backing up, it’s time to bring in the pros. These could be signs of deeper issues like a cracked sewer line, clogged vent stack, or main line blockage.

At All Pro Heating, Air & Plumbing, we specialize in diagnosing and resolving drain and sewer problems, especially the sneaky ones that show up after storms. Our camera inspections, drain cleaning tools, and experienced techs help you get to the real root of the problem (not just mask the smell).

We’ll Clear the Air (and the Pipes)

No one should have to light a dozen candles and cross their fingers after every rainstorm just to keep their bathroom from smelling like a swamp. The odors you’re noticing are more than just unpleasant—they’re a warning sign that your plumbing system needs some attention.

Whether it's a simple clog or something deeper in your sewer line, All Pro is here to help. We serve homeowners all across Central Indiana with honest advice, fast service, and no overcomplicated upsells. Just straightforward solutions from a team you can trust.

Let’s Get That Smell Gone—for Good

Storms may be unavoidable, but post-storm plumbing problems don’t have to be. If your shower drain smells worse every time the clouds roll in, it’s time to take the next step.

Need service today? Have No Fear! All Pro is Here! Call us today, and let us track down the source of the stink, so you can breathe easy again, rain or shine.