Last Updated on October 4, 2026 by Umar Farooq
A tub clean cycle is maintenance for the parts of the washer you cannot see, and it is the only cycle on the machine that runs with the intention of cleaning the machine rather than the laundry. It is not a fault, not a diagnostic, and not something the washer runs because it detected a problem.
It also does considerably less than every article about it implies. The cycle washes the drum, the outer tub the drum spins inside, and the plumbing between them. It does not touch the door gasket folds, the detergent drawer, or the drain pump filter — and those three are where the smell almost always is. Tub clean is one of four maintenance jobs on a washing machine, not the maintenance job, and running it a third time is the wrong response to a machine that still smells after two.
The cycle appears under different names by brand: Tub Clean, Self Clean, Self Clean+, Clean Washer, Drum Clean, or Pure Cycle on older machines. They are the same idea with different marketing.
What tub clean does that a normal hot wash doesn’t
One clarification before the comparison, because these three get mixed up constantly: tub clean runs empty and cleans the machine, a hot wash cleans laundry, and a sanitize cycle cleans laundry biologically by holding a high temperature. They are not interchangeable — the sanitize cycle explained sets out which does what.
Four things separate it from any wash cycle: water hotter than a normal wash on most machines, a far longer soak, an agitation pattern built for scouring rather than for fabric, and an empty drum. But the difference that actually explains why a hot empty wash is not a substitute is water level — the tub clean cycle fills higher than any cycle you can select for laundry, and that is what lets it reach a space a normal wash never touches.
A washing machine has two drums. The inner one, perforated, holds your laundry and spins. The outer one, sealed, holds the water. During a normal wash the machine deliberately keeps the level low, because that is the entire efficiency argument for a modern washer — a fraction of the water, driven through the fabric rather than the fabric floating in it. The consequence is that the outer tub, the space between the two drums, is never fully flooded during ordinary use.
Residue collects in exactly that gap. Detergent that never dissolved, fabric softener, body oils, lint, and the biofilm that grows on the mixture. It sits on surfaces that ordinary wash water reaches at a level and never above it, which is why you sometimes see a grey tide line on the outer tub of a machine that has been opened up. Tub clean is the only cycle that fills high enough and agitates long enough to move water across that surface.
| Normal hot wash | Tub clean cycle | |
|---|---|---|
| Water level | Low, sized to the load | High, fills toward the outer tub |
| Water temperature | As selected | Hottest the machine will supply |
| Drum contents | Laundry | Empty by requirement |
| Agitation | Gentle enough for fabric | Aggressive reversals and spin bursts |
| Duration | Typically under 90 minutes | About an hour top-load, several hours front-load |
| Rinses | Fixed by cycle | Extended and repeated |
| What it targets | The clothes | The tub, drum and internal plumbing |
How often to run a tub clean cycle
Samsung is the brand that publishes a specific trigger rather than a vague recommendation, and the numbers are worth knowing because they show what the engineers considered normal: the Self Clean reminder appears after 20 washes on a top-load model or 40 washes on a front-load model (how to clean your Samsung washer). Roughly monthly for an average household, in other words, with front-loaders given twice the interval before the machine says anything.
Most other brands land in the same neighborhood with a monthly recommendation and no counter behind it, and real-world practice spreads wider still — anywhere from monthly to every three months is defensible depending on how hard the machine is worked. If yours has no reminder and no documented interval, monthly is the default to beat, and it matters far more that this happens at all than that it happens on the right week.
The exception is a machine that already smells, and this is the part nobody expects: one cycle will not clear an established odor. Biofilm that has had months to establish itself does not come off in a single pass, and the remedial approach is to run tub clean once a week for three consecutive weeks, then drop back to monthly. Almost everybody runs it once, gets a marginal improvement, and concludes the cycle does not work. It does — it just needs three goes at a backlog.
Run it sooner than your usual interval if any of these are true:
- You have been washing cold, or washing heavily soiled loads, for several weeks.
- You have been over-dosing detergent — see white residue on clothes if that is showing up on your laundry.
What to put in it — and what not to
Nothing, in most cases. The cycle is designed to work on water, heat and time alone, and manufacturers generally state that no additional cleaner is required. That instruction gets ignored constantly, because starting an empty washer with nothing in it feels like you have forgotten a step. You have not — the empty drum is the specification, not an oversight.
If odor is the actual complaint rather than routine maintenance, liquid chlorine bleach is the one additive that is broadly sanctioned, and it goes in the detergent dispenser compartment, up to the maximum line — never poured directly into the drum. Neat bleach sitting on the drum surface can mark stainless and attack the gasket, and the dispenser exists precisely so that it enters diluted and at the right point in the cycle. Do not combine it with anything else in the drawer.
Vinegar is the popular internet answer and it is a poor one: a weak acid with limited effect on established biofilm, and sustained exposure is not something rubber seals and metal fittings benefit from. Anything that foams is worse still — powdered oxygen cleaners included — because foam sits between the water and the surface you are trying to clean, which is the exact opposite of what a high-water empty cycle is for. Your normal laundry detergent belongs in the same category: it adds to the residue you are removing.
| Additive | Verdict |
|---|---|
| Nothing | Correct for routine maintenance |
| Liquid chlorine bleach, in the dispenser | Acceptable for odor; never into the drum |
| Proprietary washer-cleaning tablets | Optional — follow the tablet’s instructions and your manual |
| Your normal laundry detergent | No — adds residue, may over-suds |
| Vinegar | No — weak on biofilm, hard on seals |
| Anything that foams | No — foam blocks the water contact you want |
Safety: never mix bleach with another cleaning product in the dispenser. If a strong chemical smell lingers after the cycle, ventilate the room and run a plain rinse rather than a second bleach cycle.
Tub clean is one of four maintenance jobs
Every guide to this cycle treats it as complete maintenance, and that is the assumption worth breaking. Tub clean moves water, so it reaches every surface water reaches and nothing else — which sounds obvious until you notice that three of the four places a washing machine goes wrong sit outside the water path entirely, and all three are more likely to smell than the tub is. The cycle does exactly one of the four jobs. The other three need a cloth or a physical removal, no cycle on the machine will ever do them for you, and that is why someone who has run tub clean twice and still has odor needs the gasket rather than a third run.
The door gasket on a front-loader is the first. The rubber boot has a fold in it, a lip designed to keep water inside the drum, and that fold traps water, lint, hair and the occasional sock. It is warm, dark and permanently damp, which is the entire specification for growing mold. Water flowing past during a cycle does not get into the fold, because preventing exactly that is the fold’s purpose. You have to pull it back and wipe inside it.
The detergent drawer is second. It sits upstream of the drum, so cycle water flushes through the channel but never scrubs the compartment corners or the underside of the drawer housing, where fabric softener in particular sets into a gel. The drawer comes out — usually with a release catch at the back of the center compartment — and it goes in the sink.
The drain pump filter is third and the most consequential, because it holds solid debris in standing water permanently. It sits downstream of everything, it is designed to catch what the pump cannot pass, and nothing in a tub clean cycle disturbs it. LG documents a monthly cleaning interval for it, and also notes that the filter is “only present on LG frontload washers and combo units” and is “not available on top load washers” (how to clean the drain pump filter). That generalizes across brands: most front-loaders have a filter behind a small door at the bottom front, most top-loaders have none.
| # | Maintenance job | Done by tub clean? | What it takes | How often |
|---|---|---|---|---|
| 1 | Drum, outer tub and internal hoses | Yes — the whole point of the cycle | Run tub clean, empty | Monthly |
| 2 | Door gasket fold (front-load) | No | Pull the fold back, wipe it out, dry it | Weekly, and after every wash if you can |
| 3 | Detergent drawer and housing | No | Pull the drawer out, wash it in the sink | Monthly |
| 4 | Drain pump filter (most front-loaders) | No | Unscrew, drain into a tray, rinse the mesh | Monthly |
Which job your symptom actually points to:
- Musty smell from an empty, closed drum — job 2 first, then 3 and 4. Job 1 is the least likely cause and the one everybody tries.
- Black speckling on the door seal — job 2, and no number of cycles will touch it.
- Sticky gel or crust in the dispenser — job 3. See detergent not dispensing if it has also stopped releasing product.
- Smell strongest low down, or slow drainage with it — job 4. See washing machine drains too slowly.
- Grey flakes on laundry, or a tide line inside the drum — job 1. This is the one tub clean genuinely fixes.
If your machine has a reminder light
On most machines that light is a counter rather than a sensor — it tracks washes since the last clean, not how dirty the drum is. Two things follow. It can appear on a machine you cleaned last week, and a normal hot wash will not satisfy it no matter how hot, because the thing being counted is the completion of one specific cycle. An interrupted or cancelled run generally does not count either, which on a front-loader means committing several hours in one block.
Samsung’s implementation is the one most readers are dealing with, and it is worth reading properly if the light itself is your complaint: Samsung Self Clean light stays on covers the documented intervals, why unplugging the machine does not reset it, and how to tell the reminder light from the cycle-selection light on the panel.
Confirm it did something
- Wipe the drum with a light-colored cloth. Grey on the cloth means residue is still coming off, and a visible sludge line means run it again.
- Leave the door and the detergent drawer open for a few hours, then smell the drum cold. Warm and damp masks odor; cold and dry does not.
- Run one normal load and smell the laundry when it comes out. That is the test that actually matters.
- If it still smells, do not run a third cycle. Go to jobs 2, 3 and 4 — gasket, drawer, filter.
When the cycle isn’t the answer
- Odor persists after a completed cycle and after cleaning the gasket, drawer and pump filter.
- Water is standing in the drum when the cycle ends — that is drainage, not cleanliness. See washing machine won’t drain.
- Visible black mold on the gasket returns within days of being cleaned, which usually means a gasket replacement rather than more cleaning.
- The machine leaks during the cycle. The high water level in tub clean exposes seal and hose failures a normal wash never reaches — see front load washer door leaking.
FAQ
How long does a tub clean cycle take?
About an hour on most top-loaders and several hours on most front-loaders. The long soak at temperature is the mechanism, so a cycle you cut short has not done the job.
Can I put laundry in it?
No. It uses agitation and spin patterns that are not safe for fabric, and a load absorbs the water that is supposed to be flooding the outer tub.
Why does the drum still smell after running it?
Two reasons, and they stack. An established odor needs three weekly cycles rather than one. And if it survives that, it is coming from the gasket fold, the detergent drawer or the pump filter — none of which tub clean reaches.
How many times do I need to run it if the machine already smells?
Once a week for three consecutive weeks, then back to monthly. One run on a months-old buildup gets you a partial result and the wrong conclusion.
Does tub clean fix an oversudsing error?
It helps, because accumulated detergent residue genuinely contributes to repeat suds pauses. The dosing has to change too — see Samsung washer Sud or 5d error.
My washer drains slowly and smells. Same cause?
Often, yes — both point at the drain path rather than the drum. See washing machine drains too slowly.
Should I leave the door open between washes?
Yes, and it does more for odor than the cleaning cycle does. A drum that dries out cannot grow anything.
