Being a very lazy person, I get tired of vinegar spraying the inside of my dehumidifier's water basin every week. It's a highly compact machine, and the water basin is has an odd shape, with all sorts of hinged doohickeys at the top (which is the opening), so it takes a bit of dexterity to ensure that I coat all of the interior, deep down to the bottom.

After spraying liberally, I let the basin marinate in the vinegar for about 20 minutes before rinsing it out, then wiping down the outside. Since the bottom has complex contours, I jiggle the basin every few minutes to ensure a fresh layer of vinegar on the surfaces that are not at the lowest point. It's not exactly a hands-off process.

One way to avoid the need for this might be to simply pour a few table spoons of vinegar into the basin whenever I empty it out (daily), and leave the vinegar in there while the dehumidier operates. It will mix with the condensed water extracted from the air, and be in constant contact with the bottom of the basin. The top of the basin, which doesn't touch liquid water (but might be exposed to high humidity air due to the water in the basin) doesn't get contacted with vinegar with the exception of one of the side walls during the emptying of the basin.

Has anyone ever tried this? Does it actually make it unnecessary to do the weekly disinfecting? Would the constant exposure to vinegar harm the plastic? Would the lack of exposure to vinegar of the top part of the basin (including the complex doohickeys) be at risk of developing grime, mildew, or mold? Does it make the home smell like vinegar all the time? Would that be bad for one's lungs?

I also wonder whether it would be just the smell of vinegar in the air, whether the vapour in the air would actually be acidic. If so, then in the long term, constant exposure could harm all things exposed to the air, e.g., books, plastics, fabrics, HEPA filters, etc.

Just wondering about the overall wisdom of indulging my laziness....

  • 1
    Why do you believe vinegar disinfects the humidifier? It is used to remove CaCO3, lime. Commented Nov 28, 2017 at 3:35
  • I'm intrigued where you got the idea that you need to clean the reservoir every time you empty it. I run a dehumidifier constantly for about 6 months of the year and have never once cleaned the reservoir. It is not CLEAN but then it's also not obviously contaminated with mould or anything else. The water that drops into the reservoir is pretty cold, I would have thought this is a fairly harsh environment for a living organism...?
    – Lefty
    Commented Nov 28, 2017 at 10:10
  • What's the point in cleaning it every week? Generally killing bacteria & mould (is that a problem after just a week)? Getting rid of hard water stains / calcium deposits (like DrMoishePippik's comment)?
    – Xen2050
    Commented Nov 30, 2017 at 4:34
  • I might be misconceived about disinfecting...I was thinking that vinegar is use to treat mold, which arises in wet environments. As well, only use dehumidifer in the winter because the windows are closed, and I left water in the reservoir for one summer, which caused a layer of icky goo (gross). As well, vinegar was recommended for the water reservoir of a humidifier (rather than a dehumidifer), so I assumed that the same logic applied. As diluted acetic acid, it does have disinfectant properties. Commented Dec 2, 2017 at 3:29
  • I don't know if weekly is too often to prevent mold or any other bad thing, but this is a preventative measure. I don't want to wait long enough for bad things to grow before treating the reservoir. BTW, I don't currently disinfect every time I empty the reservoir. I was simply think of constant exposure to vinegar as an alternative to current practice. Commented Dec 2, 2017 at 3:30

6 Answers 6


My concerns about damage due to the vinegar were well founded. I used my dehumidifier as a sacrificial guinea pig. When I emptied out the water bin, I sloshed in about half an inch of vinegar. I noticed that the condensed water leaking into the bin had a blue tinge. See the right side of:

Blue Stain

I did not expect that it was due to corrosion of the metal in the heat exchanger, since it was very blue; in contrast, the only colourful oxidized metal that I knew of was copper, and it rusted green.

So I took apart the front to look at the coils and fins. The entire assembly looked bluish:

Cooling fins with blue colouration Cooling fins with blue colouration Cooling fins with blue colouration Cooling fins with blue colouration

A web search reveals that heat exchangers are typically made with copper coils and aluminium fins. In my dehumidifier, the tubing that the fins are anchored onto are copper, and the fin themselves are some gray-silverish metal. The blue seems to be coming from the copper tubing. That is probably the source of the blue staining in the water bin. The vinegar is probably evaporating through the short plastic tubing connecting the water bin to the heat exchanger compartment -- there's no other open pathway to anywhere else (though the gaseous vinegar can escape through seams between plastic parts in much smaller quantities).

As further evidence that the vinegar is passing through the heat exchanger compartment, the screws at the front of the compartment are rusted. So the vinegar gas is entering the compartment, then escaping through the plastic grill on the front (basically, the air intake vent). There are other screws near the front, but more off the the side, and they are less rusted. The parts of those screws that are nearest to the front grill are more rusted.

Conclusion: Prolonged marinating of the water bin with vinegar is not advisable, as it will damage the metal components of the heat exchanger, and fastening screws. I only hope that it isn't damaging the humidity gauge.

  • You are destroying your dehumidifier and your health. The vinegar is corroding the copper and the vapour you create by doing this ill-advised procedure not healthy to inhale. Simple chemistry — bad practice. Read the instruction manual and comply with the recommended procedures for operation and maintenance.
    – Stan
    Commented Feb 19, 2018 at 16:06
  • Yes, but before my experiment, the prevailing wisdom was just the opposite. The whole question was motivated by the desire for a lazy hack. The manual doesn't speak to this. if it had worked, it would have been a positive bit of knowledge. But there was no way to know without actually trying it. Commented Feb 21, 2018 at 3:45

Eucalyptus works great to kill mold, but it tends to degrade plastic especially soft plastic like washers, etc. It could shorten the life of the dehumidifier.


Vinegar is a liquid, and the dehumidifier wouldn't put that back into the air. Also, vinegar is a very weak acid, and if you're that worried about your books, try something like rubbing alcohol. It'll clean better and won't damages your things.

  • I do have isopropyl alcohol, which I use to disinfect/clean around areas with rust-able metal. If I add it to the emptied reservoir, the alcohol will evaporate, leaving the condensed water behind. It won't provide the continuous disinfecting effect that I describe in my original post. However, it might still help. Thanks. Commented Dec 2, 2017 at 3:57
  • BTW, I mentioned vinegar evaporating into the air because when I spray down areas with vinegar, I still smell it when I get back many hours later. I assume that the vinegar enters the air through evaporation, and detectable amounts remain based on the smell. However, the evaporation from the dehumidifer water reservoir would likely be limited due to the enclosed space. Commented Dec 2, 2017 at 4:01
  • @user2153235 You are breathing-in the vapour you created when you "spray down" with vinegar. The odour is from your own vaporization rather than evaporation.
    – Stan
    Commented Feb 19, 2018 at 16:15
  • I'm not inclined to picture the physical process that way. The spray bottle creates tiny droplets, which do not stay airborne. If the smell is present hours later, it can only be due to evaporation. In the answer that I posted, the photos show that vinegar does evaporate, and it attacks the metal that the vapor comes into contact with. Commented Aug 29, 2018 at 1:29

I'm not certain of the effects on the components, but Eucalyptus oil will help mitigate bacteria/fungus/mold growth and smells in the basin. You will have to add more when you empty the basin.

  • Thanks, reeky2001. I will take it under advisement. At the moment, I'm hesitant to put oil in the bin because it would not be easily rinsed away. There are intricate components, such as vertical tubes with a floating bob to serve as a water level indicator. The 1st photo also shows a hinged thing on the left. In contrast, vinegar can be rinsed away, and it's the most established substance for this kind of purpose. Commented Feb 19, 2018 at 13:18

I have 3 dehumidifiers, all different makes, and all designed so they can have a rubber hose attached for continuous drainage. I experienced persistent problems with all 3 of them when operated in continuous drain mode because the drip rate (hence flow rate) of water into the pipe was very low, hence I found the tubes blocked regularly with some sort of mouldy slime. I reasoned that the dehumidifier action of drawing air through would supply the water collecting on the vanes with a constant source of dust and mould spores and hence eventually develop this slime

My solution to the problem, which may fit quite well with your desire for a lazy (efficient!) water bin maintenance was to:

  • source some 8mm rubber tubing
  • drill a 7mm hole in the side of the water bucket about 2/3rds up between the bottom of the bucket and the max water level permitted by the float
  • cut one end of the tube at 45 degrees - this makes it easier to thread through the hole
  • push the tube through far enough that it can reach all the way down so the pointy end is touching the bottom of the bucket, the 45 degree cut will also prevent it fully contacting the bottom and blocking itself
  • position the dehumidifer vertically above where you want the condensate to drain into (sink, toilet, even just out of a window, the greater the height difference between the bottom of the bucket and the free end of the pipe, the better
  • fasten the free end of the pipe to the draining point

What happens now, is your bucket will fill as the dehumifier operates. The water level rises in the bucket and the pipe. At the moment where the water level in the bucket reaches a height that is level with the highest part of the pipe, a siphon will start and the bucket will be quickly drained into wherever you put the free end of the pipe. Because the water flow rate is higher than the slow dripping achieved by the normal continuous drain offered by the manufacturer, the inside of the tube stays clear. The free end of the tube can additionally be placed very far from the position of the dehumidifier, and it can go up and down a lot, so long as no part of its run is higher than the highest level of water in the bucket, a siphon will start. This means you could eg place your dehumidifier on a 2m high shelf, run 10metres of tube down to the floor along to the other side of the room, up to a 1m window sill and out to a drain outside. As long as there is an appreciable height difference between the bottom of the bucket and the free end of the pipe, the siphon will completely empty the tank, suck the pipe clean and then the whole setup is ready to start again

Now, this doesn't disinfect the bucket of the dehumifier, but I typically find that my bucker empties itself several times a day and while there is indeed still a bit of detritus on the inside of the bucket (I wouldn't drink out of it) it doesn't smell or fester. You could reduce the level of attention your bucket needs to a once monthly session in the dishwasher. I haven't bothered, and one of my dehumidifiers hasn't been attended to for 4 years now, it dries a storage room that I occasionally visit and the condensate waters a plant pot outside the window through which I drilled a hole for the free end of the tube

If you ever want to return your dehumifier to bucket mode, the simplest solution is to drill another 7mm hole in the bucket, above the max level the water can reach and then snip a short length of pipe to connect the two holes together, meaning water cannot escape through the lower hole as the bucket fills

  • Thanks, Caius Jard. I appreciate the engineering bent in your solution. Unfortunately, my situation is a bit restrictive for jury rigging tubing to a drainage point. I live in a 1-bedroom apartment with wall-to-wall carpeting and 2 sinks (kitchen & bathroom). Due to the limited room, the options for where to put the dehumidifier are limited: On the rug in the living area. Commented Aug 26, 2018 at 15:16
  • The siphon tubing will also leave a layer of water at the bottom of the basin, so I would still have to go through my routine of marinating the bottom with vinegar, although I would then also have to deal with the drilled hole in doing so. However, I appreciate that fact that you have found it to be workable. I'm cognizant of the possibility that I may be targeting a stricter level of control. I'm not worried about the point at which there is smell, as that's too loose a threshold. I want to remove sliminess from the basin, which is mostly on the bottom of the basin. Commented Aug 26, 2018 at 15:16
  • You can tip the dehumidifer slightly so the whole unit, including drain tank is angled towards the pipe, minimising the amount of water left at the end of a siphon. Consider though, that your deh is in continuous operation, and even if you manually emptied the tank and wiped it dry every time it was full, within a few minutes it would again have a similar amount of water in the bottom, as it would with the siphon method. By "targeting a stricter level of control" I read "seeing a theoretical problem where, in practice, none really occurs" ;)
    – Caius Jard
    Commented Aug 28, 2018 at 16:29
  • In terms of placement advice, consider fitting a shelf to the wall adjacent the bathroom/kitchen, and routing the pipe through the wall. Small holes are easily repaired if it's rented :) but remember that siphons can take circuitous routes. Actually, stepping back another level to the original problem of "i need a deh" - WHY do you need a deh? Your apartment should not be letting rainwater, or plumbing leaks in, so why is it humid? Inadequate ventilation+drying clothes on radiators/cooking/showering? Perhaps you need to address a problem that is one stage before the use of the deh
    – Caius Jard
    Commented Aug 28, 2018 at 16:33
  • Stricter level of control doesn't mean theoretical at all. I've left water in the basin before, and it becomes a thick gruesome layer of sludge. Yet there was no smell. Using the absence of smell as an indicator of effectiveness is looser than the threshold that I want. The tubing approach is not ideal for my problem because, as I said, it leaves a portion of the basin submerged, so I still need to use vinegar to prevent a buildup of grime. Routing tubing and having a permanent drain into a sink is OK for a basement, but not for a small apartment with only kitchen and washroom sinks. Commented Aug 29, 2018 at 1:25

You can put a plastic bag inside the bucket like a garbage bag. When you dump water remove bag and put a new one. You can reuse the bags after washing them and wash them when you have time and wash multiple ones. Just make sure they don't touch anything hot. Using a hose with float is good if you aren't home to empty it, but usually results in more mold and slime and make it much harder to clean.

  • I think it would be less effort to spray with vinegar, let sit for a bit, then rinse. But thanks for offering the suggestion. Commented Aug 6, 2019 at 1:49

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