[supernova87a]

I would suggest that this is actually more efficient.

When people use the toilet on planes, the design of the toilets uses so much less water than a toilet on the ground, in the airport, and how much a flush of water takes.

So if you assume that people were going to use the bathroom regardless, they just saved the processing of a lot of water by doing it on the plane. Probably ounces versus gallons. (~100 mL vs. 1-2 L)

(parenthetical note, sometimes I wonder if a vacuum toilet would become available for home use, it's so effective!)

Now certainly, flying around to use the bathroom used up a lot more energy, but regardless... Also, you might ask whether people tend to drink more than average because they're offered drinks on a plane.

I used to wonder, considering the hundreds of pounds of water/soda/etc loaded on a plane, as people drink and consume it all, wouldn't it be efficient for the plane to dump that water in flight and save the weight and extend the range. Turns out (of course) that is so negligible compared to the overall weight of the plane...

[brnt]

> parenthetical note, sometimes I wonder if a vacuum toilet would become available for home use, it's so effective

I've heard it said that plumbing issues dramatically increase with modern, water-efficient toilets. It's not hard to imagine why. Sewer usage and maintenance are at a far lower rate, so stool will settle and clog when ever smaller amounts of water are introduced.

I'm not sure this problem can be solved, assuming regular sewage as the method of disposal.

[l1tany11]

A lot of problems are also due to old systems. Ask any plumber. The plastic pipes are smooth inside. Old pipes weren’t only rough, they degrade. Cast iron sloughs off into itself. There was a kind of pipe that was used that was basically tar paper; it broke down and clogged itself (like cast iron).

A new building with new toilets should work very well. Replacing your toilet may not help if your pipes from the 60s are basically nonexistent.

[mveety]

Orangeburg pipe is the tar paper stuff. It's a time bomb. Not only does it break down with use it also flows (flattens with gravity/overburden pressure, bends over unsupported sections run through walls/floors, etc) over time as well, especially in a hot environment. So even if it doesn't get much use it will collapse and/or stretch and break.

[brnt]

Indoor pipes still can be horizontal for long stretches, where smoothness doesn't help if it's flushed only a few times per day. It also depends on the stool. I never cause obstructions, but my wife on the other hand...

[GekkePrutser]

Drinking in a plane is also note necessary because the air is pretty low in humidity. It sometimes even gives me nosebleeds on long flights.

However I mean non alcoholic drinks of course, alcoholic ones dehydrate even more. I rarely drink alcohol on planes for this reason. But this is often what people drink because it's free.