The situation

Illustrative example. Not a real job or customer.

In this invented example, a two-story townhome in Aurora is empty for most of July. When a prospective tenant visits, the entry smells faintly like a sewer and the landlord worries that the plumbing is failing.

  1. The landlord returns and notes the smell is strongest in the lower-level bathroom and near the laundry area.
  2. The floor drain in the laundry closet is dry, and so is the trap under a seldom-used basement sink.
  3. Water is poured into each drain, followed by a small amount of mineral oil on the floor drain to slow evaporation.
  4. The shower in the basement is run for a short time, and the toilet is flushed.
  5. The landlord returns the next day at the same hour to compare the smell.

In this illustration, the smell is gone after the traps are refilled, and the landlord adds a trap check to the weekly vacancy visit. If it had remained, the next step would be a plumber's inspection.

Facts the example highlights

Likely cause
Trap water evaporated over a warm, dry vacancy
First fix
Refill every trap, especially floor drains and unused fixtures
Follow-up
Recheck at the same hour the next day
When to escalate
If the smell persists after refilling, ask a plumber to inspect

Repeatable routine drawn from the example

  1. Locate every drain

    Include floor drains, tub drains, laundry standpipes and basement sinks that are easy to forget.

  2. Fill with water

    Pour enough to refill the trap and watch that it drains normally.

  3. Slow evaporation where useful

    Where a floor drain is rarely used, some landlords add a thin layer of mineral oil or install a trap seal device.

  4. Log it

    Note the date and the drains refilled so a later visit knows what was done.

Common questions

Why add mineral oil to a floor drain?

A thin layer on top of the trap water can slow evaporation. Some landlords prefer a manufactured trap seal; either way, check it during vacancy visits.

Does this example replace a plumber visit?

No. It is an invented scenario. A persistent sewer smell, slow drains or backups deserve a qualified plumber.

Could the smell have another cause?

Yes. Vent problems, cracked pipes and failing seals can all produce a similar smell. The example assumes dry traps because the house had been empty for weeks.

General information for Aurora, not a quote or professional advice. In an emergency, call 911.