Unpleasant odors coming from a washing machine drain are a serious issue that can lead to tenant complaints and even move-outs. Causes range from problems with the drain trap to dirt buildup inside the washing machine itself, so the right response depends on the underlying cause. This article explains the causes of drain odors, effective countermeasures, and the preventive steps rental property owners should take.
What causes a washing machine drain to smell?
There are several possible causes of drain odors. Identifying the cause correctly is the first step toward an effective solution.
Buildup of dirt and debris
When lint, hair, dust, and other debris accumulate in the drain, bacteria can grow and cause bad odors. The longer a washing machine has been in use, the more buildup it tends to have, and the stronger the odor may become.
Loss of trap seal water
A drain trap is a mechanism that holds water in the pipe to prevent sewer odors from rising indoors. If the washing machine is not used for a long period, the seal water can evaporate and sewer smells may spread into the room. If the trap has dried out, slowly pour water into it to restore the seal.
A detached or damaged drain trap
If the drain trap has come loose or is damaged, the water seal can no longer function properly. For that reason, it is important to check the condition of the trap regularly.
Using leftover bathwater
When laundry is washed with leftover bathwater, bacteria in the water can transfer into the washing machine and cause odors. Be sure to use tap water for the rinse cycle.
Can the type of odor help identify the cause?
The likely cause varies depending on the type of odor.
| Type of odor | Main cause |
|---|---|
| Fishy or musty rag-like odor | Mold and bacterial growth inside the wash tub |
| Sewer-like odor | Evaporated or detached trap seal |
| Soap or mold odor | Undissolved detergent residue and a dirty drain |
How should drain odors be addressed?
How to clean the drain
- Move the washing machine to access the drain
- Remove the drain trap and take the parts apart
- Remove dirt with a brush and a neutral detergent
- Pour pipe cleaner into the drainpipe and leave it for 30 minutes to 1 hour
- Rinse thoroughly with water and reinstall the trap
Cleaning the wash tub
About once a month, clean the tub using a washing machine cleaner or an oxygen-based bleach. Using water at 40 to 50 degrees Celsius improves cleaning effectiveness.
Everyday preventive measures
- Leave the lid open after washing so the inside can dry
- Use the proper amount of detergent to prevent residue
- Replace the drain debris net regularly
- Refill the trap seal if the machine will not be used for a long period
What measures should rental property owners take?
- Provide tenants with a usage guide：Give written instructions on how to clean the drain and what precautions to follow
- Clean the drain at move-out：Include drain and trap cleaning as part of restoration work when a tenant leaves
- Schedule regular pipe cleaning：Prevent clogs through professional pipe cleaning about once a year
- Inspect the drain trap：Check during vacancy periods whether the trap seal has dried out
Frequently Asked Questions (FAQ)
Q. How often should the drain be cleaned?
Cleaning it about once a month is ideal. If odors are a concern, increase the frequency to once every two weeks.
Q. If the drain trap is damaged, who pays for the repair?
If the damage is due to normal wear and tear, the landlord is responsible. If improper use by the tenant caused the damage, the tenant is responsible.
Q. Can a store-bought pipe cleaner eliminate drain odors?
It can be effective if the odor is caused by light buildup. However, if the cause is a detached drain trap or damaged piping, pipe cleaner alone will not solve the problem.
Q. If the washing machine will not be used for a long period, is odor prevention necessary?
Yes. Because the trap seal water can evaporate, we recommend pouring about one cup of water into the drain once a month.
