Ok, I have no clue how the toilets work... Is the waste dumped while in the air at all, or is everything done on the ground?

Are there 2 sources of water (one potable, one not), or do they all come from one tank? and if so, is it potable?

(yeah, I know, I've got too much time in my hands to be thinking about this...)

Mods, can you please edit the title to "how do"? thx

http://travel.howstuffworks.com/question314.htm

Definitely not dumped in flight (or while on the ground). Just like a boat, train, or RV, commercial airplanes have some sort of septic tank and use vacuum toilets.

Sorry for the above. I posted before I really read the article. It's really about vacuum toilets on airplanes. You want to know about the green chunks of frozen stuff that fall to earth in urban legends, right?

Think RV. They have holding tanks that contain waste matter until ground crews drain them. Likewise, they have potable and non-potable tanks of water. You should not drink from the faucet in the restroom. Other faucets are questionable, as one recent survey found up to 20% of all potable water sources on planes were found to have some strain or other of e-coli bacteria (not necessarily harmful unless you have a weak immune system).

Then again, I'm certainly not an expert. Others have written on the subject in this forum. Might try searching.

I wouldn't lump all trains in the category of having holding tanks. At least until the early '90s, Amtrak trains didn't, and you were requested to not use the on board toilets at the stations. Some (maybe all, I'm not sure) Amtrak trains got tanks starting in the early to mid '90s. Before that I remember reading the occasional cautionary tale in the newspaper about fishing under railroad bridges when somebody reported learning the hard way. I'm pretty sure that in much of the less developed world, direct track dumping is still common.

According to this account, the occasional "blue ice bomb" is not because of flushing to the outside, but because of leaks in the plumbing that allow a generally small amount of fluid out. At altitude, it freezes as it escapes, forming a block of ice, as the plane descends to warmer temps, it drops the bomb.

All of the non-blue water is theoretically potable, but there have been several accounts of random testing that have found a variety of bacteria and such that would not be healthy to ingest. The tanks are apparently not disinfected on a very regular basis, washing my hands is about the extent of how far I would go with it, certainly not drinking or teeth brushing.

Thank you all for the replies!^

What got me thinking about this was some incident with the Dave Mathews band in Chicago, in which their bus tour driver dumped their "dump" (pardon the pun...) while crossing a bridge, and some passengers on a boat right below the bridge at that time were not very happy...

On all modern airplanes with vacuum toilets there is only one source of water. It connects to the coffee makers and the toilets. There is a one-way check valve at the toilet connection that is supposed to prevent contamination of the system.


Just thought that Inquiring minds would want to know.

Not too many years ago, on a regional in Spain, I recall seeing the ties flashing by under the toilet. . .

Also not too many years ago Amtrak trains transiting Denver had to shut down their (holding tank) toilets while within the city limits.

For all I know, they still do.

The same is true of houses and apartments; toilets and drinking taps are attached to the same system.

All current Amtrak trains have holding tanks in each car - and they're emptied at the end of the run. That's why you may see a "Out of Order" sign on some rest rooms, but not on the ones in the next car.

True, the cars from years ago did not. That's why you could see the tracks when you flushed.

I don't know about other countries, but I'm sure many trains do not.

If the toilet water is connected to the general water supply, at what point is the water made blue? Seems to me that the toilet water is in a different tank.

Also, many smaller boats (not the cruise lines) also dump directly into the sea. Most of the live-aboard diving boats that I've been on dump directly into the ocean, thus the warning not to use the head while diving/snorkling groups are in the water (if possible)......

One of the first of these surveys, I believe, was conducted by (then) 13 year old FTer, - T-wiz - see here.

Modern vacuum toilets do not have blue water, the old style tanks have blue water and in that case you are correct. But all newer planes with vacuum toilets have the flush water connected to the potable water tank.