What might cause an odour?
A floor drain’s water trap can dry out after a long period without use, allowing sewer-like odours to travel back through the opening. Residue, a nearby source or another drainage condition may also contribute; smell alone cannot identify the cause.
Note whether the drain is used regularly, when the odour appears and whether other fixtures or floor drains are involved. Avoid reaching into the drain or removing a grate that does not lift easily.
What can you safely check?
If there is no standing wastewater and the drain is not backing up, a modest amount of clean water may refill a dry trap. Stop if water rises, drains poorly or returns; do not add chemical cleaner or mix products.
If the smell quickly returns, is strong, or occurs with gurgling or backup, describe the pattern and arrange an assessment. Keep people away from any wastewater and treat active backups differently from an odour alone.
When should you seek more help?
A persistent odour, multiple affected drains, or water appearing where it should not be deserves a closer look. For an immediate health or building-safety concern, contact the appropriate local emergency or utility service.
Tell a provider which drain is involved, whether it is used often, what you observed and whether any water is standing. These details support a conversation, not a remote diagnosis.
Frequently asked questions
Related next steps
Floor drain cleaning in Ottawa · What to do when a drain backs up · Tell us what the drain is doing.
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