A sewage or rotten smell drifting from a drain is your plumbing telling you something specific — and the fix depends entirely on which cause it is. Here is how to diagnose and clear drain odour in a Johannesburg home.
Cause 1: a dried-out trap (most common)
Every drain has a U-bend "trap" that holds a little water to block sewer gas. In a guest bathroom, a floor drain or a rarely-used sink, that water simply evaporates — and gas rises into the room. The fix is delightfully simple: run water into every drain, including the ones you never use, to refill the seal.
Cause 2: a partial blockage
Hair, grease and food debris caught in the trap or pipe rots and smells. Clean the visible trap and remove buildup. If the smell returns, the blockage is further down and needs proper drain cleaning.
Cause 3: a venting fault
If the smell comes and goes — worse in wind, or when a toilet is flushed elsewhere — your drainage venting may be faulty, letting pressure changes pull sewer gas through the traps. This is a system issue, not a simple blockage, and should be assessed by a plumber.
The kitchen-sink special
Kitchen drains smell from grease buildup more than anything. Avoid pouring fats down the drain, and have the waste run mechanically cleaned periodically.
When to call us
If refilling traps and cleaning does not fix it, the cause is downstream — a building blockage or a venting defect that is best sorted before it becomes a backup. Book a drain inspection; for recurring issues we run a CCTV camera to find the exact cause.