Why Your Kitchen Sink Smells Like Rotten Eggs in the Summer in Michigan

You walk into your kitchen on a hot summer day, and instead of smelling coffee or breakfast, you’re hit with a foul, sulfur-like odor coming from the sink. It’s unmistakable—rotten eggs.

If this sounds familiar, you’re not alone. Many homeowners report that their kitchen sink smells like rotten eggs in the summer in Michigan. The cause? Usually a combination of heat, bacteria buildup, venting issues, and sometimes, a simple dry trap.

Here’s what’s really going on inside your pipes—and how to fix it before your whole kitchen stinks up the house.

It’s Almost Always Hydrogen Sulfide

That rotten egg smell? It’s likely hydrogen sulfide gas.

This gas is produced when organic material (like food scraps, grease, and soap scum) breaks down in a low-oxygen environment—like the inside of your kitchen drain.

While small amounts won’t harm you, it’s still a major red flag that your plumbing system isn’t draining or venting properly.

Summer Heat Makes It Worse

In Michigan, summer heat amplifies plumbing problems—especially smells. When the temperature rises, so does the rate of bacterial activity inside your pipes.

Heat speeds up decomposition of waste sitting in your drain or P-trap. Combine that with humidity and stagnant water, and suddenly your kitchen becomes a breeding ground for odor-causing bacteria.

In short, what might be a minor issue in winter can quickly turn into a stinky nightmare by mid-July.

Common Causes of Kitchen Sink Odors

Let’s break down the usual suspects behind that foul smell in your summer kitchen sink:

1. Dry or Evaporated P-Trap

The P-trap is a curved pipe under your sink designed to hold water and block sewer gases. But if you haven’t used the sink for a while (or have a second kitchen or wet bar), the water in the trap can evaporate—especially in the heat.

Once it’s dry, there’s nothing stopping that rotten sewer gas from coming straight into your home.

Fix: Run water down the drain for 30–60 seconds. If the smell goes away, a dry trap was the cause.

2. Organic Buildup in the Drain

Food waste, grease, coffee grounds, and even soap residue can stick to the walls of your drain pipes. Over time, bacteria break it all down—and that’s when the hydrogen sulfide gas forms.

In summer, this gunk decomposes faster, especially if the drain isn’t used often or flushed properly.

Fix: Pour ½ cup baking soda followed by 1 cup of vinegar down the drain. Let it fizz for 10–15 minutes, then flush with boiling water. Enzyme drain cleaners can also help break down the gunk safely.

3. Clogged or Blocked Vent Stack

Your plumbing system includes a vent stack that lets air into the pipes and sewer gas out through the roof. If that vent is clogged (by leaves, bird nests, or snow remnants), pressure builds and sewer gas can get forced back into your home—especially from drains on the first floor.

In older Michigan homes, these vents are often undersized or corroded.

Fix: A licensed plumber can inspect and clear the vent stack using specialized tools. Don’t climb up yourself unless you know what you’re doing.

4. Grease-Coated Pipes

Michigan homeowners love their fried food—but pouring hot grease down the sink is a recipe for long-term plumbing trouble.

That grease may go down hot, but it cools and sticks to pipe walls. Over time, it traps food debris, which decomposes and releases that nasty smell. And guess what? Summer heat softens and activates those fatty deposits even more.

Fix: Avoid pouring grease down the drain. Flush existing buildup with a degreasing enzyme product or call for a professional hydro jetting.

Is It Dangerous?

While the smell itself is unpleasant, a sulfur odor from your drain can signal deeper issues:

• Sewer gas exposure (in large amounts) can cause headaches or nausea.
• Blocked vents or slow drainage can lead to backflow or flooding.
• Bacteria-rich buildup can worsen over time and cause damage to your plumbing system.

Bottom line? Don’t ignore it. If your kitchen sink smells like rotten eggs in the summer in Michigan, it’s time to take action.

When to Call a Pro

Sometimes, DIY methods aren’t enough. Here’s when to pick up the phone:

• The smell comes back repeatedly, even after cleaning the drain
• You notice gurgling sounds when other fixtures are used
• The odor is accompanied by slow drainage or backup
• You’ve already tried vinegar, baking soda, and boiling water with no luck

A professional plumber can use a camera inspection to identify any hidden blockages, collapsed pipes, or venting issues that a surface clean won’t fix.

They may also recommend hydro jetting to clean out grease and buildup, or repairing faulty traps and vent lines.

Keep Your Kitchen Smelling Fresh All Summer

You don’t have to live with that rotten egg smell all season. With the right diagnosis and fix, your sink can go back to being a functional, fresh-smelling part of your home.

And if you’re not sure what’s causing the odor? Don’t guess. Call someone who knows Michigan plumbing inside and out. Sometimes this can be a handyman plumber too.