Why Does My Water Smell Bad?

Bad-smelling water is usually caused by bacteria, hydrogen sulfide gas, pipe corrosion, sediment buildup, a water heater issue, or a drain problem. If the smell only happens at one sink, it may be the drain. If the smell happens throughout the home, especially with rusty water, metallic taste, or low pressure, the plumbing system may be breaking down internally.

We always tell homeowners: the smell is usually not the real problem. The smell is the clue.

First, Figure Out Where the Smell Is Coming From

Before blaming the pipes, do this simple test. Fill a clean glass with water from the faucet, then walk away from the sink and smell the water in the glass.

If the glass smells normal but the sink area smells bad, the problem may be the drain. If the water itself smells bad away from the sink, the issue may be in the water supply, water heater, or piping system.

That distinction matters because drain problems and supply-water problems are very different.

Rotten Egg Smell

A rotten egg smell is often linked to hydrogen sulfide gas, which can be produced by sulfur-reducing bacteria in groundwater or plumbing systems. Sometimes the smell shows up only in hot water, which can point toward the water heater as the source.

If only the hot water smells, the water heater should be checked first. If both hot and cold water smell throughout the home, the issue may be deeper than just the water heater.

Common causes include:

• Sulfur bacteria
• Water heater reactions
• Stagnant water
• Well water conditions
• Buildup inside older pipes

A rotten egg smell can also be confused with sewer gas or even gas-related odors, so if the smell is strong, sudden, or not clearly coming from the water, it should be taken seriously.

Musty or Earthy Smell

A musty smell can come from organic material, bacteria, old drains, or stagnant water. In older plumbing systems, sediment and corrosion can create rough pipe walls where buildup collects.

Musty water becomes more concerning when:

• It happens at multiple fixtures
• It keeps coming back after flushing
• The home has old pipes
• Water pressure is also weak
• Water is discolored

At that point, the problem may not be the faucet. It may be the pipe system.

Metallic Smell

A metallic smell often points toward minerals, corrosion, or deteriorating pipes. If the smell comes with metallic taste, rusty water, green corrosion, or low pressure, that is a strong sign the water is picking up material from inside the plumbing system.

Old galvanized pipes can release rust particles. Copper pipes can corrode under certain water conditions. Either way, metallic smell is usually a warning sign that something inside the pipe is changing.

Sewer-Like Smell

If the smell is more like sewer gas than bad water, the source may be a drain, dried P-trap, clogged drain, vent issue, or sewer gas problem. A sulfur-like smell in a house can also come from drains, sewer gas, water heaters, or other non-water-line sources, so the source needs to be identified before assuming it is the water supply.

That is why the glass test matters. Water smell and drain smell can feel similar, but the repair path is completely different.

When Bad-Smelling Water Means a Plumbing System Problem

Bad-smelling water becomes more serious when:

• The smell happens throughout the home
• Both hot and cold water are affected
• Water is yellow, brown, or rusty
• Water tastes metallic
• Pressure has dropped
• The home has galvanized or aging copper pipes
• The issue keeps returning after flushing

When smell shows up with water color changes or pressure problems, we start looking at the system, not just one fixture.

Will a Filter Fix Bad-Smelling Water?

Sometimes. A filter may improve odor if the issue is water quality entering the home. But if the smell is caused by corroded or deteriorating pipes, a filter is only a bandage. It may improve the water after it passes through the filter, but the pipes behind the wall are still breaking down.

Repair vs Repipe

A repair may make sense if the smell is only at one fixture, the issue is from the drain, the water heater is the source, or the rest of the home's water is normal.

A repipe may be the better long-term fix if the smell is throughout the home, water is rusty or metallic, pressure is weak, pipes are galvanized, or you have recurring leaks or corrosion.

Frequently Asked Questions

Why does my water smell like rotten eggs?

It may be hydrogen sulfide gas, sulfur bacteria, or a water heater issue.

Why does only my hot water smell bad?

If only hot water smells, the water heater is often the first place to inspect.

Can old pipes make water smell bad?

Yes. Corrosion, sediment, and buildup inside old pipes can contribute to recurring odor problems.

Will a filter fix bad-smelling water?

Sometimes, but not if the source is failing pipes.