Sewer Smells in Bathroom After Rain

Sewer smells in a bathroom that appear only after rain indicates that the source of the smell is introduced to the house’s plumbing from the groundwater.

Rain and Water Supply

Sewer gases in your bathroom may contain toxic or combustible gases that put your safety at risk.Sewer gases in your bathroom may contain toxic or combustible gases that put your safety at risk.
Hydrogen sulfide will produce a rotten egg smell, or a smell similar to a sewer. A professional water test will indicate if your house has a problem with hydrogen sulfide as well as sulfates.

As rain water contacts the ground, the water will take the path of least resistance through the soil. Sometimes this path leads the rain water through decaying plants or other decaying organic material, which contains sulfide. Some rocks in the soil also contain sulfides. The water picks up the sulfides and continues on to your house’s well or the city’s water reservoir. As you use different plumbing fixtures in your house, the water contaminated with sulfides runs into the house.

Sulfate Presence

Depending on the concentration of the sulfate in your house’s water supply, you may notice a bitter taste in the water. Bacteria living in your house’s water supply system, particularly in the hot water side of the system, oxidize the sulfide in the water supply. Sulfates in the water system my leave deposits around and in plumbing fixtures, similar to the calcium and magnesium deposits hard water leaves. As the bacteria oxidizes the sulfides in the water, the bacteria produces a black slime that will eventually clog the water supply lines and has a corrosive effect on metal.

Hydrogen Sulfide Presence

Hydrogen sulfide in the water produces the rotten egg smell in the bathroom as the water enters the toilet’s tank and bowl as well as the other plumbing fixtures. If you run the hot water in your bathroom, such as in the sink or shower, the heat in the water will cause the rotten egg smell to increase. If left unchecked, the hydrogen sulfide will corrode metals, including copper, and will leave yellow and black stains in the plumbing fixtures.

Health Risks

Sulfates in a house’s water system will act as a laxative to anyone who consumes the water, presenting a risk of dehydration from diarrhea. As a person’s body adjusts to the sulfate levels in the water, that person will no longer experience bowel problems. Higher sulfate levels will minimize the effectiveness of detergents, meaning the washing machine and dishwasher will not clean as well as before. Besides smelling, hydrogen sulfide will affect the taste of foods cooked in tainted water.