A musty smell coming from a kitchen sink often indicates the presence of bacteria or fungus. Bacteria thrive in kitchen sinks because of the moist environment and food particles that are often caught in the drain.
Remove bad smells by cleaning the sink with chemical cleaners or natural remedies. Natural remedies include everyday household items, such as lemon juice, salt, vinegar or baking soda. When using chemicals to clean a kitchen sink, homeowners should never mix certain chemicals together, such as ammonia and bleach. Ammonia is a chemical found in many over-the-counter cleaners, including Drano. Mixing it with bleach forms a chloramine gas, which is poisonous to humans and animals.
If natural remedies and chemicals do not get rid of the musty smell, homeowners should check that they have a p-trap installed under their sink. The p-trap is a “u” shaped pipe located directly under the sink. It traps water in the pipe to prevent foul sewage gases from traveling through the pipes and getting into the house. Without a p-trap in place, these gases have a direct route into the house. The water trapped in the p-trap is continuously replaced with fresh water every time that sink is used.