5 Common Causes of a Strange Well Water Smell

A woman in a yellow top holding a glass cup of water, looking at it questionably.

Strange smelling well water is an unnerving experience for even the most seasoned homeowners. While you may be quick to conclude the water supply is bad, there are many reasons why strange odors may have leaked into your system. From sulfur to musty and sewage odors, here are five common strange well water smells and their causes.

1. Rotten Egg Smell

Sulfur is the typical culprit behind the infamous rotten egg smell. There are a number of ways sulfur bacteria can enter the well, but the most common is the absence of oxygen, which creates sulfide gas. You may also be dealing with chemical reactions that contain sulfur in nearby groundwater. The best way to treat sulfur is to purchase an aeration system for the well. These systems dissolve the bacteria using catalytic carbons mixed with dissolved oxygen. You can also shock the system with a chlorine injection to get rid of the rotten egg odor.

2. Musty Odors

A silver faucet with a hot water tap.

An earthy or musty smell in the water typically only happens when using the hot tap. This smell is caused by an excess amount of iron in the water. Fortunately, a musty smell does not mean the water is harmful, though it can lead to a foul taste. You also might notice a buildup of slime in the toilet and plumbing around the house, which is another indicator of iron buildup. You can clean out the excess iron by using a chlorine chemical feed and installing an iron filter to prevent future problems.

3. Fishy Aroma

A fishy odor in the water is usually from organic materials that have leaked into the well. These materials often elevate certain levels of elements in the water, including barium, cadmium, and chloramines. Barium and cadmium are metals that naturally occur in deposits and can infiltrate plumbing and pipes. Chloramines, however, are a mixture of ammonia and chlorine and are often used as a water disinfectant. Fortunately, none of these materials pose any harm to drinking water. You improve the smell by using reverse osmosis or carbon-based filters.

4. Sewage Stink

Running soapy suds down a stainless steel sink.

A sewage odor can be the result of leftover bacteria in the drain or when a hot water heater hasn’t been in use for long periods of time. The gas sticks in the drain until the water is turned on and is forced out. You can find the origin of the smell by first filling a glass with tap water. If the water inside the glass smells, then you know the problem is with the water source. If there is no odor in the glass, then simply run some soap and water down the pipes to allow the gas to fully drain.

5. Chlorine Smell

A swimming pool smell isn’t typically associated with well water, though homes near water distribution plants might suffer from high levels of chlorine. While chlorine is great for treating city water, it doesn’t do any good if it leaches into the home. Not only does it give off a foul odor, but it can also dry out your skin. You can remove excess chlorine by installing a specialized water filter in your home.