Sometimes the machine is clean, the clothes are clean, and the laundry room still smells. People chase it by cleaning the washer again, which does nothing, because the smell was never coming from the washer.
A laundry room is a small space containing standing water, warm damp air, and a drain. There are several things in there that can smell, and only one of them is the machine.
Work out where it is coming from
Before treating anything, narrow it down. Two minutes.
Open the washer door and put your head near the drum. If the smell is stronger there, it is the machine.
Put your nose near the standpipe or the drain the hose empties into. A sewer or rotten smell here is the drain, not the machine, and it is the most commonly missed cause.
Check whether the smell is worse when the machine has not run for a day or two, or worse right after a cycle. Worse when idle points at the drain. Worse after running points at the machine or the room’s humidity.
Pull the machines out and smell behind and underneath them.
The drain, which is the answer more often than people think
The standpipe your drain hose goes into has a P-trap below it, the same as a sink. That trap holds water, and the water is what blocks sewer gas from coming back up.
If the machine has not run for a while, that water evaporates. The trap dries out, and sewer gas comes straight into the room. This is extremely common in a laundry room that only gets used at weekends, and it is why the smell is worse when the machine has been idle.
The fix is free: pour a couple of litres of water down the standpipe. If the smell goes, that was it. In a room that gets little use, do that monthly.
If refilling the trap does not fix it, the other possibilities are a venting problem, which shows up as gurgling when the machine drains, or buildup in the drain line from years of lint, detergent, and grease. Gurgling and slow draining together mean a plumber rather than a cleaning product.
One thing not to do: do not pour drain cleaner into a laundry standpipe as a first move. It is harsh on the pump and seals if any of it gets back into the machine, and it rarely addresses a dry trap, which is the usual cause.
The room itself
Assuming the drain is fine and the machine is clean, look at the space.
Damp laundry waiting to be washed. A hamper of towels and gym clothes in a closed room is doing exactly what a damp cloth does. Hampers want ventilation, and wet items should dry before going in one.
The floor under and behind the machines. Small slow leaks, drips from a hose connection, and condensation all end up under there and nobody looks. Pull the machines out once a year. A damp patch under a washer is both a smell and a warning.
Lint accumulation. Behind and beneath a dryer collects lint that holds moisture and dust. It is also a fire consideration.
The dryer duct. If it has come loose at the back, the dryer is venting warm humid air straight into the room, which will make the room damp and smelling no matter what else you do. Check the connection is sealed.
Anything stored in there. Cardboard boxes, old rags, cleaning supplies with loose lids. Cardboard in a damp room holds moisture and smells.
Ventilation, which is usually the underlying issue
Most laundry rooms have no ventilation at all. A closet with a door and no window and no fan.
A washing machine puts moisture into a room. So does opening a hot dryer. So does anything hung to dry. With nowhere for it to go, the room stays humid and everything in it stays slightly damp.
The fixes, in order of effort. Leave the door open, which is free and does most of it. Put a fan in there and run it after laundry. Fit a vented louvre door if it is a closet. Add an extractor fan if the room genuinely has none. A small dehumidifier solves a closed laundry closet outright and is worth it in a house where this is a recurring problem.
The Tempe angle, which is the opposite of most places
This is a dry climate, and that changes the diagnosis in a specific way.
In a humid city, a smelling laundry room is usually a humidity problem. Here it usually is not. Ambient air is dry enough that damp fabric and damp rooms dry on their own, and the humidity explanation that fits most of the country fits this one badly.
What that means practically: in Tempe, a persistent laundry room smell points at the drain far more often than at the room. Dry P-traps are more common here precisely because evaporation is faster. A trap that would last two months elsewhere can dry out in a few weeks here.
So if you are here and the room smells, start with a jug of water down the standpipe before you do anything else. It is free and it is the likeliest answer.
Two other local points. A garage laundry gets extremely hot in summer, and heat accelerates anything growing in a damp hamper or a machine left closed. And hard water leaves scale in the drain path and on the standpipe rim, which holds residue that holds smell.
The order to work through it
Pour water down the standpipe and wait a day. Leave the washer door and dispenser drawer open permanently. Pull both machines out, clean the floor, and check for damp and loose ducting. Run an empty hot cycle with vinegar in the washer. Deal with the hamper. Then improve ventilation.
Most laundry room smells are gone by step two.
When the room is beyond a quick fix
Sometimes it is a plumbing job, or a long-standing damp problem, and the laundry still has to happen.
The machines at our self-service laundry on East Baseline Road will take a household’s laundry in one visit while the room at home gets sorted out, and the higher extraction means everything comes back properly dry rather than damp.
Our machines and the store are cleaned daily, and that includes the floors, the drains, and the space around the machines rather than only the drums.
Nou wash-dry-fold service covers everyday laundry in the meantime.
The short version
Find the source before treating anything: smell the drum, then the standpipe, and note whether it is worse when the machine has been idle. A dry P-trap in the standpipe is the most commonly missed cause, and pouring a couple of litres of water down it is free. Gurgling plus slow draining means a plumber instead. Then check the floor under the machines, the dryer duct connection, and the hamper. Most laundry rooms have no ventilation at all, and leaving the door open does most of the work. In this dry climate, traps evaporate faster than elsewhere, so start with the standpipe.
WaveMAX Tempe is at 222 E. Baseline Rd., easy to reach from Tempe and the surrounding area. If your laundry room is out of action, call us at 480-278-9685.