I am about to begin a bar installation project. I need an ice maker. There appear to be two kinds of free standing ice makers - those that do and do not require drains.

Why does one type need a drain?

Are there other differences between these two types?

Are there any definitive advantages of one type over the other?

Is there standard placement for floor drains, or do I need to purchase and have the specific unit on hand before the plumber places the drain?

4 Answers 4


Most commercial-grade ice makers don't maintain freezing temperatures in the actual ice bin; the ice itself keeps the temperature cold in the bin, and the refrigerator coil then only has to freeze the ice tray. This strategy has several advantages:

  • The "cold" side of the refrigeration coil can be placed inside the bin, right against the tray, so it makes ice faster than your "frost-free" kitchen freezer icemaker, without needing to be defrosted (because it doesn't have to maintain freezing temperatures, it defrosts itself automatically between batches).
  • The coil and overall refrigeration system is thus more efficient at what it does (making ice quickly).
  • The ice is easier to scoop as it doesn't melt and refreeze when exposed to the bin door opening and closing.
  • The ice is "warm ice" which, again, won't try to refreeze after it melts in your drink (forming that big ice ball you get from cubes or crushed ice from your kitchen freezer.)

But, the downside is that the ice is continually melting and must be replaced with new ice, and the melting water has to be drained. Commercially, the amount of water lost to melting is usually pretty low because the ice is consumed relatively fast, but there is some and it does have to go somewhere. Your kitchen freezer, at about 0*F, can maintain hard frozen ice indefinitely, so it doesn't need a drain and it only has to replace the ice at the rate it's used, which is a good thing because the ice tray relies on ambient air temperature to freeze the water, instead of active transport of heat by the clooling loop in contact with the tray. Similar "home-grade" ice makers are smaller in size and keep the ice frozen. These are good for the occasional large party, but they just don't make ice fast enough for a drink station at a restaurant or concessions stand.

As far as placement, the drain line can pretty much be anywhere and go anywhere, as long as it goes into the sanitary sewer and obeys all other code regarding slope, length to the nearest vent stack, etc. There is a big difference between your basement floor drain and the one in a professional kitchen; the one in your basement was designed to drain relatively clean water either from a plumbing failure or from weeping through the basement walls. It ties into the municipal storm sewer, an "open" sewer designed for precipitation, which will dump any water you put in it directly to the nearest creek. Professional kitchen floor drains tie into the sanitary line, which is the "sealed" sewer that carries food and bodily wastes and cleanser residues from most of your interior drains out to the wastewater treatment plant where those wastes are removed. So, if you buy an ice maker that needs a floor drain, you will need to have a drain specially installed that feeds into the sanitary line. The design is pretty standard; a 3 or 4-inch line, with or without a grate over it, that drops straight down about a foot into a J-trap, and from there to the main sanitary trunk line. This drain will need a backflow preventer on it.


All ice makers produce a great deal of waste water, most of which is condensation from the compressor. The ones without a drain collect this water into a reservoir of some kind which you need to empty on a regular basis. If the reservoir fills up, the machine won't produce new ice. The drained versions will simply drop the condensation down the drain. If it were me I'd go for a drained version if I could run a pipe over to an existing drain conveniently as the self-drainers tend to be cheaper and more convenient as you don't have to empty them all the time, but if there's no convenient drain I'd buy one with a reservoir.

  • I could be wrong but don't some without drains have a fan over the waste reservoir to evaporate the water?
    – UNECS
    Sep 17, 2012 at 9:44
  • 1
    From what I've seen these are designed to drip any excess water onto the floor, or just do so anyway. Basements tend to be damp, making it harder to evaporate condensate, and you don't want to be adding more moisture to the air in a basement anyway. @bjb would need to put a drip pan of some kind over this type and would always be worried about it overfilling.
    – GdD
    Sep 17, 2012 at 9:53
  • The compressor is always the hot half of refrigeration equipment and will not create condensation under any conditions. The condenser might. Jan 18, 2013 at 22:49
  • Some of the units without a drain recycle the water, not a good option for a commercial system as this would require more frequent cleaning. Ice machines can be a big health hazard if not regularly sanitized, I don't remember the cycle count but a drain system can usually go at least a week with city water 3-4 days with well water. the recirculation type was shorter by half and then you have to remove the chemicals although some say no rinsing required if it kills the bugs I don't want it in my glass or in my cooler.
    – Ed Beal
    Feb 16, 2018 at 20:27

It depends upon the type of ice being made.

Hard Ice - Ice machines without drains usually make ice in a mold that has to freeze the water solid. They keep the temperature well below freezing keep the ice solid (no melting of ice and no wasted water). This is like most ice makers that are in refrigerator/freezers. This ice can get stuck together at the bottom of the bin.

Soft Ice - Ice machines with drains have a continual flow of water over the freezing surface. They keep the temperature of the ice right around freezing to keep the cubes from sticking together. In this process the ice is continually melting (but stays soft/chewable) and the water has to be sent to a drain.

A standard drain (floor or sink) will work as long as it is below the ice machine drain and close to the ice machine. You can use either hard or soft piping.


Often when you are talking about a standalone ice maker you are really talking about something called "clear ice". Needless to say, these ice makers produce perfectly clear ice that tastes amazing--no white air bubble and no garbage or sediment from your water source.

The way these ice makers work, in general, is to run water over a plate or shoot water into a "bell" that is cooled by a refrigerant. Since the surface is freezing, the running water will eventually begin to freeze in slow layers and the heavy sediment just gets pushed away by the water. So what you end up with is perfectly clear, pure ice.

Rather than just wasting all the water that runs over the plate but doesn't ice up right away, a recirculating pump pushes the water back up over the tray. Once the thermistor by the plate registers that it is cold enough, it reverses the flow of the refrigerant in the system, simultaneously defrosting the system and heating the plate up. When the plate gets hot enough, the ice melts where it is touching the plate and then slides down the incline to a wire grid that melts its way through the clear sheet of ice-creating perfect cubes of amazing clear ice.

In the models that use jets to force the water up into a refrigerated "bell" shape, the same thing happens when the refrigerant is reversed. The bell becomes hot and melts the first layer of ice and gravity drops the ice bells into the bucket--no cutting needed.

So while this process is happening, the recirculating pump sits a little bit higher in a reservoir than the bottom. That way, all of the heavy sediment collects in the bottom and only the clean water gets recirculated. When the "harvest" happens and the refrigerant is reversed, the inlet pump runs the entire time. This causes all of the water in the reservoir to rise and push out all of the old water (along with the sediment and other impurities).

The wastewater is then combined with the water from the melted ice and comes out the back of your icemaker. A gravity-drain icemaker requires a floor drain so that the water can just drain out of the unit without needed a pump.

This is almost always the best plan though some people will argue. The reason it is the best plan is that you are completely protected should you be out of town and the power goes out. The melted ice will simply run down the drain. With a pump-drain system, the water collects in a waste reservoir until it reaches a certain level. At that point, the drain pump is activated and the wastewater can be pumped into a drain (under your sink like the dishwasher drain works well). Needless to say, if the electricity goes out, your ice will overflow the reservoir and flood your room or back up until all of your ice is ruined.

The best units come with a drain pump that has a secondary trigger that turns the interior recirculation pump off if the waste reservoir gets too full (say if your drain pump fails).

I have had the pleasure of owning 3 of these clear ice makers in my life and I have built and rebuilt and combined and recombined them and I cannot emphasize enough how great the ice is every time. Granted it's not nugget ice, but it doesn't cost 6 grand either.

  • Good overview of the cubed process, + flaked ice is a drum that rotates in a bath and is cut or sheared as the drum rotates no clean out like cubers so they need to be sanitized more often.
    – Ed Beal
    Feb 16, 2018 at 20:39
  • My absolute favorite, nugget ice, runs water along the surface of a cylinder until it freezes...then it has a sharp blade that shaves off the top layer and feeds it down a cone into a smaller cylinder forming a shaved ice pencil shape that gets cut every inch or so...it's squishy and delicious, but expensive. I am saving up the 5k for one as I write this. LOL Thanks for the comment. Feb 19, 2018 at 14:09

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