A drain often smells bad because food, hair, soap and other gunk have built up inside it and started to break down. A drain that is rarely used, a dirty sink overflow or a problem elsewhere in the plumbing can also cause odors.
A smell does not always mean something is wrong with the pipes. It is still a sign worth paying attention to, especially if it keeps coming back or shows up along with slow draining.
Buildup Inside the Drain
The most common cause is plain buildup. Kitchen drains collect grease and food bits. Bathroom drains collect hair, soap scum, toothpaste and skin care products. Over time this material can coat the inside of the pipe and give off a sour or musty smell.
Buildup can also slow water down, which gives it more time to collect even more debris. That is why a smelly drain and a slow drain often show up together.
Other Possible Sources of the Odor
If buildup is not the cause, other things may be involved. These include:
- a rarely used sink, tub or floor drain where the water in the curved trap has dried out
- dirt and mildew in a bathroom sink overflow opening
- food left in a garbage disposal
- a loose or damaged drain connection under the sink
- venting or other plumbing issues that need a closer look
The curved trap under a drain is meant to hold a little water, which helps block odors from the pipes beyond it. In a guest bathroom or a unit that has been empty for a while, that water can dry up.
A drain odor does not automatically mean there is a sewer problem. It is also not always coming from the drain at all. Trash, a damp cabinet or a nearby fixture can smell similar, so check the area around the sink too.
A Safety Note About Gas Smells
A rotten egg or sulfur smell can come from a drain, but it can also be a sign of a natural gas leak. If you think you smell gas, do not try to find the source. Leave the area right away, avoid using light switches or phones inside, and call 911 or your gas company from a safe place.
When Drain Cleaning May Help
Running water in drains you seldom use and cleaning the sink overflow with soap and water can help with mild odors. Avoid pouring harsh chemicals into a smelly drain, and never mix cleaning products.
If the smell keeps returning, gets stronger or comes with slow draining or gurgling, it may be time for professional drain cleaning. Cleaning the line can remove the buildup that is causing the odor. In apartment buildings, let the super know if neighbors notice the same smell.
Have a drain in your Bronx home that just will not stop smelling? Call (929) 209-6183 and we can take a look and help you find out what is behind it.
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