There is a sewage smell in the building

Start with the drains nobody uses. Pour several liters of water down every floor drain, unused restroom, mop sink and rarely used sink in the affected area, then wait an hour.

That single action resolves a large share of sewage smells in commercial buildings and it costs nothing.

Why an unused drain smells

Every drain has a trap, a bend that holds a plug of standing water. That water is the only thing between the room and the drainage system, and it works entirely by being there.

A drain that is used regularly refills its trap every time. A drain that is not loses that water to evaporation, which in this climate happens fast. Floor drains in mechanical rooms and store rooms, drains in a restroom nobody uses, mop sinks, condensate drains and drains in a space that has been closed for a while all dry out on a scale of weeks.

Refill them, and add a small amount of cooking oil on top of the water, which floats and slows the next evaporation considerably. Then put the rarely used ones on a monthly refill so it does not recur.

When the water does not fix it

If the smell persists after every trap in the area has been refilled, the cause is something in the drainage system, and the candidates narrow quickly.

A vent problem. Drainage systems need venting to work, and a blocked or damaged vent causes water to be siphoned out of traps as other fixtures discharge. The signature is a smell that appears shortly after somebody uses a fixture elsewhere, and gurgling from a drain when another one runs.

A failed seal under a toilet, which produces a smell at floor level near the pan, sometimes with a loose or rocking fixture.

A grease trap on too long an interval or with a failed seal, which in a kitchen is the most likely cause after dry traps. Our article on grease traps in a Miami kitchen covers the interval and the manifests.

A cracked or displaced pipe in a wall, a void or under a slab is the least common cause and the most involved to fix.

Mapping it before anybody attends

Note where the smell is strongest and where it cannot be detected at all. Note the time of day it appears and whether it coincides with anything: exhaust fans starting, a cleaning round, a delivery, a busy service.

Note whether it is worse in warm weather or after rain. A smell that is markedly worse after heavy rain suggests something in the below-ground drainage rather than a trap.

Run the faucets on any fixture near where the smell is worst and listen for gurgling elsewhere. Gurgling is a venting symptom and it is worth reporting explicitly, because it points somewhere quite different from a dry trap.

Why this matters beyond the smell

Sewer gas in a room is a maintenance failure in an occupied space, and in a food operation it is an inspection finding. Our article on the maintenance items behind a health inspector citation covers where it sits alongside the other building findings.

It also tends to be reported late. Staff acclimatize to a smell over days and stop mentioning it, so by the time it reaches a manager it has usually been present for a while. If a customer raises it first, the problem has already cost more.

Who is allowed to do the work

Refilling a trap is anybody. Everything past that is plumbing, and Florida requires a licensed plumbing contractor for plumbing work at any job size. Clearing and repairing drainage, working on vents, resetting a fixture, camera surveying a line and grease trap work all sit there, and the size of the job does not change it.

TrionX coordinates that contractor and documents the visit. Where the work needs access opened up, our own technicians handle the doors, the drywall, the tile, the ceiling and the making good afterward.

Keeping it away

Put a monthly trap refill on the maintenance schedule and name the drains on it, because the ones that dry out are exactly the ones nobody thinks about. It takes a few minutes and it is the cheapest recurring task on any commercial property.

Add it to the quarterly property walk as well, particularly for areas that are seasonally unused, and to the reopening checklist for any space that has been closed.