Ask a Master Plumber: Why Does My Water Smell? - Lujan Plumbing

Sometimes your nose is the first sign that something isn't right with your water. Here's what those smells could mean and what you should do about them.

Most homeowners expect their tap water to be clean and odor-free. So when you turn on the faucet and notice a strange smell, it can be concerning. In many cases, the smell is harmless and caused by naturally occurring minerals or harmless bacteria. Other times, it can indicate a plumbing issue that should be addressed sooner rather than later.

As a master plumber, I've seen just about every type of water odor there is. Below are some of the most common smells homeowners notice and what they usually mean.

• Common Causes: Bacteria, minerals, water heaters, municipal treatment chemicals, or plumbing issues.
• Good News: Most water odor problems are fixable with the right diagnosis.

Let's break down what those smells could mean.

The Rotten Egg Smell (Sulfur)

One of the most common complaints homeowners have is water that smells like rotten eggs.

This smell is usually caused by hydrogen sulfide gas, which can naturally occur in groundwater or develop inside your plumbing system.

Possible Causes

• Sulfur bacteria in your plumbing system
• A water heater issue
• Groundwater containing sulfur
• Bacteria reacting with the magnesium anode rod inside a water heater

If the smell is only coming from hot water, your water heater is often the culprit. The anode rod inside the heater can react with naturally occurring bacteria and produce that sulfur smell.

What To Do

• Flush your water heater
• Replace the anode rod if necessary
• Install a filtration system if sulfur exists in the water supply

If you're unsure, it's best to have a professional inspect the system to pinpoint the source.

A Chlorine or Chemical Smell

If your water smells like bleach or a swimming pool, you're probably detecting chlorine.

Municipal water suppliers often add chlorine to disinfect water and kill harmful bacteria. While this makes water safer to drink, it can sometimes leave behind a noticeable odor.

Why It Happens

• Higher chlorine levels during seasonal treatment
• Water sitting in pipes for long periods
• Municipal system adjustments

Possible Solutions

• Run the tap for a minute to flush stagnant water
• Install a carbon filter or whole-house filtration system
• Use a refrigerator or faucet filter for drinking water

This smell is usually not dangerous, but filtration can significantly improve taste and odor.

A Musty or Earthy Smell

Sometimes homeowners notice a smell that reminds them of dirt, mold, or damp earth.

This type of odor can occur when organic matter interacts with chlorine or bacteria inside the water system.

Possible Causes

• Organic material in the water supply
• Bacteria growing in drains or pipes
• Biofilm buildup inside plumbing

What To Check

• Clean sink drains and garbage disposals
• Run water in unused sinks to flush stagnant pipes
• Have your water tested if the smell persists

In some cases, the smell may not actually come from the water itself but from bacteria growing in the drain trap.

A Metallic Smell

If your water smells or tastes like metal, it could indicate minerals or corrosion.

Possible Causes

• Iron or manganese in the water
• Aging galvanized pipes
• Corrosion inside plumbing fixtures

Iron and manganese are naturally occurring minerals that can affect water smell and taste. If the smell is strong or accompanied by orange or brown stains, it may be time for a water quality test.

How to Identify Where the Smell Is Coming From

When diagnosing a water odor problem, one of the first things we check is where the smell appears.

Ask yourself:

• Does the smell come from hot water only?
• Is it present in every faucet?
• Does it occur only in one sink or drain?

These clues help determine whether the problem is coming from:

• The water heater
• The municipal water supply
• Your home's plumbing system
• Or simply a dirty drain

A quick inspection can usually narrow it down quickly.

When You Should Call a Plumber

While some water odors are harmless, persistent smells should always be investigated.

Call a professional if:

• The smell is strong or worsening
• It appears suddenly
• The odor is accompanied by discolored water
• The smell comes from hot water only
• You're concerned about water safety

A plumber can test your water, inspect your water heater, and determine whether filtration or repairs are needed.

Conclusion

Strange smells in your water are more common than most homeowners think, and the cause is often something simple like bacteria, minerals, or chlorine treatment. The key is identifying where the smell originates so the correct solution can be applied.

If your water smells unusual and you're not sure why, it's always better to have a professional take a look. Addressing the problem early can prevent bigger plumbing issues down the road.

Let Us Help!

Not sure why your water smells? Lujan Plumbing can help diagnose the issue and recommend the right solution. Give us a call today at 210-694-1325 and we'll take care of it.