How to Clean a Dishwasher With Gentle Sen HOCl Tablets

How to clean a dishwasher, our way: drop one to two Gentle Sen HOCl tablets straight into the empty detergent dispenser and run a hot cleaning cycle with no dishes inside. That's the whole method for the tub. Follow it with a quick spray-and-wipe of the door seal and drain using a diluted tablet solution, and you're done — no measuring vinegar, no second cycle, no separate baking soda step.

We get why this feels backwards — the appliance whose entire job is "get things clean" needing its own cleaning is a little like your toothbrush needing a toothbrush. But food scraps, hard water minerals, and grease don't disappear just because they went through a wash cycle. They settle into the filter, the seal, and the drain, and they sit there until someone deals with them directly. Below is our recommended tablet method, the classic vinegar-and-baking-soda routine if you'd rather use what's already in the pantry, why the smell has a habit of coming back, and when it stops being a cleaning problem at all.

How Often You Actually Need to Do This

Every wash cycle leaves something behind. Food particles too small for the filter to fully catch, hard water minerals, and grease from anything you didn't scrape well enough settle into the filter basket, the door seal, and the drain trap — the parts a normal cycle rinses around, not through.

For a typical household running one load a day, pull and rinse the filter every one to two weeks and run a full deep clean — our tablet method or the vinegar-and-baking-soda alternative — once a month. If you're in hard water territory or running the dishwasher daily, cut both intervals in half.

Here's the part that surprises people: a filter that's gone unchecked for a month isn't just dirty, it's actively working against you — a mesh basket that's more debris than mesh starts letting particles pass straight back onto your "clean" dishes. If your glasses have come out cloudy or gritty lately, that's usually the answer before you've even opened the door.

Start With the Filter (It Fixes Most of It)

If you only do one thing on this list, do this. The filter sits at the bottom of the tub, usually under the lower spray arm, and it's built to come out by hand — no tools required.

• 1
  Twist and lift. Most filters have a cylindrical piece that turns a quarter turn and lifts straight out, sometimes with a flat mesh screen sitting underneath it.
• 2
  Rinse under hot running water, working a soft brush — an old toothbrush is fine — into the mesh to knock loose anything caked on.
• 3
  Check the sump underneath — the open well the filter sat in — for glass shards, bones, produce stickers, and anything else that made it past the pre-rinse.
• 4
  Reseat and lock it back in. A filter that isn't clicked into place properly rattles during the cycle and stops filtering anything at all.

(A produce sticker in the sump is basically a rite of passage. We don't know why it's always a produce sticker. We just know it always is.)

We've written a longer dishwasher filter cleaning guide if yours is more stubborn than a quick rinse can handle.

Our Recommended Method: Gentle Sen HOCl Tablets

This is the method we use ourselves, and it's the one we'd hand a friend first. One tablet in the dispenser replaces two ingredients and two cycles.

• 1
  Empty the dishwasher completely. No dishes, no cutlery basket contents — just the machine itself.
• 2
  Place one to two Gentle Sen HOCl tablets directly in the detergent dispenser — the same spot your regular detergent pod goes.
• 3
  Run a hot cleaning cycle (your dishwasher's dedicated "clean" or "extra-hot rinse" setting if it has one, otherwise the hottest normal cycle).
• 4
  While that runs, dissolve one tablet in 20 fl. oz. of lukewarm water in a spray bottle — our standard Pro Strength ratio for general surfaces.
• 5
  Once the cycle finishes, spray the door seal, gasket folds, and the visible part of the drain, let it sit for a minute or two, and wipe with a cloth. No rinse needed.

No Tablets on Hand? Vinegar, Then Baking Soda

If you'd rather use what's already in the pantry, the classic method still works — it's just two ingredients and two cycles instead of one tablet and one.

• 1
  Empty the dishwasher completely. No dishes, no cutlery basket contents — just the machine itself.
• 2
  Place two cups of white vinegar in a dishwasher-safe bowl on the top rack, upright so it doesn't tip during the wash.
• 3
  Run the hottest cycle available, with the heat-dry option off. The vinegar mixes into the wash water and cuts through grease film and mineral scale as it circulates.
• 4
  Once that cycle finishes, sprinkle a cup of baking soda across the bottom of the empty tub and run a second, shorter hot cycle.
• 5
  Wipe the interior walls and door with a clean cloth once it's done. You're mopping up what both cycles loosened before it has a chance to resettle.

The Door Seal, Spray Arms, and Drain

Either method above cleans the tub. Neither one cleans these three spots on its own, which is exactly why a dishwasher can look spotless and still smell off.

Door seal. Run a finger along the rubber gasket that lines the door — it traps water and food splatter after every wash. Wipe it dry with a cloth (dampened with leftover Gentle Sen solution if you mixed some for the step above, since a five-second wipe beats digging out a separate cleaner) and check the folds for any dark spotting.

Spray arms. Pull the upper and lower arms out (most just lift off) and hold them up to the light. If any of the small jet holes look blocked, clear them with a toothpick, not a metal pin, which can widen the hole and throw off the spray pattern.

Drain. At the very bottom, under where the filter sat, there's usually a small grate over the drain opening. Clear any visible debris by hand, then let whichever cleaning cycle you ran above do the rest.

Why It Smells Again a Week Later

A dishwasher that smells right after a deep clean and doesn't a week later isn't a sign you did it wrong. Researchers who sampled the rubber door seals of household dishwashers have consistently found a biofilm living there — a thin, damp layer that hosts a mix of bacteria and fungi, including species that can survive the heat, detergent, and salt a normal cycle throws at it. That's not a defect in your machine. It's just what happens when a warm, occasionally wet surface sits closed up between uses.

The seal and the drain area are where this biofilm tends to settle in hardest, since they stay damp the longest after a cycle ends. A tablet cycle or a vinegar-and-baking-soda cycle both knock it back, but neither sterilizes the machine permanently — nothing does, short of leaving the door open between loads so the seal actually dries.

That's the real fix behind the "wipe the seal, crack the door" advice you'll see everywhere: it's not about aesthetics, it's about not giving that film the damp environment it needs to regroup. It's also why we build the seal spray into our own method above rather than treating it as optional.

When It's Not a Cleaning Problem

We'd rather tell you this now than have you run a fourth cycle for nothing. A clean, well-maintained dishwasher that still won't dry dishes, still leaves standing water, or makes a grinding noise on drain isn't asking for another cleaning cycle — it's asking for a repair tech.

Signs it's mechanical, not dirt: standing water that doesn't clear even right after a cleaning cycle, a drain pump that hums but doesn't actually pump, a float switch that's stuck (the small dome near the front that senses water level), or a heating element that's stopped kicking on for the dry cycle. None of those improve with more tablets or more vinegar.

If the filter is clean, the seal is dry, and dishes are still coming out wet, cloudy, or gritty, that's your cue to call someone rather than run another cleaning cycle.

Frequently Asked Questions