Why Does My Bathroom Smell Like Sewage? (Annapolis Plumber Explains)

Dear Tim,

This is a little embarrassing, but I don’t know who else to ask.

Our bathroom has started to smell… and the only way I can describe it is like sewage. It’s not constant, but when it hits, it’s bad enough that we don’t want to use that bathroom at all.

We live in downtown Annapolis. The house was originally older, but we completely gutted it and renovated everything, so I’m surprised we’re having this issue.

I’ve cleaned everything I can think of, and it still comes back.

At this point, I’m worried it’s something bigger going on behind the walls or under the house.

What causes that kind of smell—and is it something we should be concerned about?

— Concerned in Annapolis

Dear Concerned in Annapolis,

You’re not alone—and honestly, the fact that this is happening in a newly renovated home is actually a really important clue.

A sewage smell isn’t just unpleasant—it’s your plumbing system telling you something isn’t working the way it should. And in homes that have been gutted and rebuilt, the issue is often tied to installation details or systems not being used regularly yet.

Let’s walk through the most likely causes.

The Most Common Reason: A Dry P-Trap

Even in brand new or fully renovated homes, this is the first thing I check.

Every sink, shower, and tub has a P-trap that holds water to block sewer gases. If a bathroom or fixture hasn’t been used much since the renovation, that water can evaporate.

When that happens, there’s nothing stopping sewer gas from coming back into the home.

Before anything else, run water in all sinks, tubs, and showers for about a minute and see if the smell improves.

Renovation-Related Issues We See All the Time

In homes that were gutted and rebuilt, a few specific things can cause this kind of smell.

Sometimes a vent pipe wasn’t properly connected or sized correctly. Sometimes a cap or plug gets left in place during construction and never removed. And occasionally, we see small installation mistakes that don’t show up right away but become obvious once the home is lived in.

Even a beautifully done renovation can have small plumbing oversights that lead to big smells.

It Could Be a Venting Problem

Your plumbing system relies on vent pipes to push sewer gases safely outside.

If something is blocked, installed incorrectly, or not functioning properly, those gases can get redirected back into your bathroom instead of leaving the house.

This is something we see more often in renovations than people expect.

Check Around the Toilet

If the smell seems strongest near the toilet, the issue could be with the seal at the base.

Even in a new install, if the wax ring wasn’t set perfectly or has shifted slightly, it can allow sewer gas to escape without an obvious leak.

It’s a small component, but it can cause a big problem.

Buildup Can Still Happen—Even in New Systems

This surprises people, but even in a newly renovated home, you can get odor from early buildup.

Construction debris, dust, and initial use of the plumbing system can create a layer inside the pipes that leads to unpleasant smells, especially in bathroom sinks and showers.

A proper cleaning can often take care of that quickly.

Should You Be Concerned?

You’re right to take it seriously—but there’s no need to panic.

Most of the time, this comes down to something fixable once the source is identified. The key is not to ignore it, especially in a newly renovated home where everything should be functioning properly.

The Bottom Line

If your bathroom smells like sewage—even in a fully renovated home—it means something in the system isn’t doing its job.

It could be something simple like a dry trap, or it could be related to how the plumbing was installed during the renovation.

Either way, it’s worth getting it checked out so you can stop guessing and get back to enjoying your home the way you’re supposed to.

If you’re in Annapolis and dealing with this, we’re happy to take a look and get to the root of it.

— Tim