What Causes Certain Tap Water Odors?

Residents and customers occasionally report odors in household tap water. In most cases these odors are temporary, harmless, or related to plumbing inside the home or commercial property rather than our St. Lucie West Services District Water Treatment Processes. In addition to disinfection, we may adjust water chemistry to protect our water pipes and ensure water quality. These treatment adjustments do not pose a health risk and are regulated under state and federal standards. Below is a guide to the most common concerns and what you should know.

Chlorine Odor/Taste in Water

Chlorine is used in water treatment to disinfect water and make it safe to drink. It kills or inactivates harmful microorganisms such as bacteria, viruses, and protozoa. The odor is more noticeable during scheduled system flushings. Flushing is a planned maintenance process, consistent with EPA guidance, that cleans water mains and helps ensure continued water quality. Florida public water systems are required to maintain a disinfectant residual throughout the distribution system. For chlorine, this typically ranges from a minimum detectable residual up to a maximum of 4.0 milligrams per liter, which is the EPA maximum residual disinfectant level. Water systems carefully control chlorine levels to stay well within safe regulatory limits while maintaining public health protection.

• What residents and customers should know: The water remains safe to drink and use, even during flushing. SLWSD will notify you in advance when system flushing is scheduled.

• What residents and customers can do: Use an activated carbon filter if the smell is bothersome. Although the water that comes from our water treatment facility is safe to drink, these are often used in households to improve water taste.

Other Minerals and Treatment Additives

Why minerals are added?

We add small amounts of treatment chemicals or minerals to ensure water remains safe and compatible with plumbing infrastructure. These additions are tightly regulated federally and state-wide. Common examples include pH adjustment chemicals such as lime or sodium hydroxide, which help reduce corrosion in pipes. Corrosion control additives such as orthophosphate may be used to protect plumbing materials and reduce the release of metals from household pipes. These substances are added at very low, regulated levels and are not associated with water odors or taste issues of concern.

Rotten Egg or Sulfur Odor

The problem is not the water!

This odor is most often caused by a chemical reaction inside a water heater, especially when a magnesium anode rod is present. The reaction can create hydrogen sulfide gas, which smells like rotten eggs. This issue usually affects hot water only.

• What residents should know: The odor is not coming from the water utility. It is most likely a plumbing or appliance related issue inside the home or commercial property.

• What residents can do: Check whether the odor is present only in hot water. If it is then the issue is most likely in your water heater. Flush your water heater once a year as part of routine maintenance. Inspect or replace the anode rod, often with an aluminum or zinc rod. Anode rods should typically be replaced every three years for proper maintenance.

Water heater anode rod example (bottom shows servere corrosion):

Sewage Odor

The problem is not the water!

This odor is usually caused by a dirty drain and not the water supply. Once water goes down the drain, organic material buildup can release odors. This is most common in frequently used drains such as showers, kitchen sinks, and bathroom sinks. In bathroom drains, hair can build up into compact masses inside the drain, creating odors and sometimes backups. In kitchen sinks, grease buildup inside the “P-trap” commonly causes odors. If there is a constant odor inside the house, it may be caused by:

1. A failed vent pipe that normally allows sewer gases to exit through the roof
2. A rarely used bathroom where the P trap has dried out.
3. An incorrectly installed P-trap.

• What residents should know: This odor is not related to the drinking water system. It is a household drainage issue.

• What residents can do: Use a proactive approach regarding drain/pipe maintenance and clean drains regularly, especially kitchen sink drains! Use safe cleaning methods such as commercially available drain cleaners or a combination of baking soda and hot water. Grease buildup inside kitchen sink pipes can form a crust inside the pipe and be difficult to remove, even by drain cleaners. When this happens, often a plumber will have to be called and use heavy-duty unclogging equipment to remove these obstructions. Read more about how to to protect your pipes from Fat, Oil, and Grease.

How a P-trap works: