A slow drain is a clue. Repeated backups are a pattern.

Start with the pattern

• One fixture drains slowly or several fixtures are affected.
• Water backs up into a tub or floor drain when a toilet or laundry runs.
• There are gurgling sounds, odours, or a recent history of the same blockage.

Avoid making it worse

Repeated use of chemical drain cleaners can complicate professional diagnosis and may damage some systems. If sewage is backing up, stop using affected fixtures until the cause is assessed.

What the assessment may involve

Depending on the symptoms, a plumber may inspect the trap, branch line or main line. Recurring blockages may call for a camera inspection rather than another temporary clearing.