# Another Waterworld question about the drinking water- spoilers **URL:** \ **Category:** Cafe Society\ **Tags:** movies\ **Created:** [September 9, 2026, 3:24am UTC](https://boards.straightdope.com/t/another-waterworld-question-about-the-drinking-water-spoilers/1032914 "2026-09-09T03:24:30Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![mixdenny](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mixdenny/32/2962_2.png) [@mixdenny](https://boards.straightdope.com/u/mixdenny)\ **Post date:** [September 9, 2026, 3:24am UTC](https://boards.straightdope.com/t/another-waterworld-question-about-the-drinking-water-spoilers/1032914/1 "2026-09-09T03:24:31Z")
So the people on the atoll value hydro so much they use it for currency. But they do have a reasonable amount of technology and Old Things. They must have figured out how to distill water by then. I don’t think they had anything much in the way of fuel so it would have to be solar. The water for all those people had to come from somewhere but all they were able to make is barely enough? And what about the Smokers on the Deez? Lots of them and at least they had fuel. Would the Exxon Valdez have had a distillation plant in real life? The Mariner had that little filter system but it didn’t look too complex so it should have been scalable. In the Extended Cut there is a scene where the woman and the girl contribute their urine to the system so they can have more water. She asks the Mariner why he doesn’t use sea water. He replies it is “hard on the filter”. Reverse osmosis, I guess but what would the membrane by made of. He could still add small amounts of sea water to help out. BUT - and this is a big but - would not the extra water around the world have been fresh and thus fairly dilute overall? ---
**Author:** ![Just\_Asking\_Questions](https://avatars.discourse-cdn.com/v4/letter/j/ba9def/32.png) [@Just\_Asking\_Questions](https://boards.straightdope.com/u/Just_Asking_Questions)\ **Post date:** [September 9, 2026, 12:09pm UTC](https://boards.straightdope.com/t/another-waterworld-question-about-the-drinking-water-spoilers/1032914/2 "2026-09-09T12:09:52Z")
> [@mixdenny](#): > > BUT - and this is a big but - would not the extra water around the world have been fresh and thus fairly dilute overall? “Everyone I know has a big but. C’mon, Simone, let’s talk about your big but.”-Pee Wee Herman All the ice and fresh water makes up about 2% of all the water on the world, so it isn’t going to dilute it much at all. Also, if all the glaciers melted, the seas would rise all of about 200 feet. Catastrophic to society, but hardly “Everest is the only land left” high. Even tall buildings in NYC would have their top halves above water. ---
**Author:** ![Dewey\_Finn](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dewey_finn/32/4222_2.png) [@Dewey\_Finn](https://boards.straightdope.com/u/Dewey_Finn)\ **Post date:** [September 9, 2026, 12:48pm UTC](https://boards.straightdope.com/t/another-waterworld-question-about-the-drinking-water-spoilers/1032914/3 "2026-09-09T12:48:51Z")
I wondered about that ending. It seemed to imply a huge amount of additional water. Unless something caused the land to sink. ---
**Author:** ![Horatius](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/horatius/32/3572_2.png) [@Horatius](https://boards.straightdope.com/u/Horatius)\ **Post date:** [September 9, 2026, 1:17pm UTC](https://boards.straightdope.com/t/another-waterworld-question-about-the-drinking-water-spoilers/1032914/4 "2026-09-09T13:17:12Z")
> [@Just\_Asking\_Questions](#): > > Even tall buildings in NYC would have their top halves above water. “I was looking for _dry land_, not _dry floorspace!_” ---
**Author:** ![AlsoNamedBort](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/alsonamedbort/32/3213_2.png) [@AlsoNamedBort](https://boards.straightdope.com/u/AlsoNamedBort)\ **Post date:** [September 9, 2026, 4:14pm UTC](https://boards.straightdope.com/t/another-waterworld-question-about-the-drinking-water-spoilers/1032914/5 "2026-09-09T16:14:55Z")
> [@Dewey\_Finn](#): > > I wondered about that ending. It seemed to imply a huge amount of additional water. Now that raises a good point. If there was additional water added to earth to raise the sea level to Everest (like from a comet) and it was fresh water, what would be the resulting salinity of the ocean? ---
**Author:** ![Dewey\_Finn](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dewey_finn/32/4222_2.png) [@Dewey\_Finn](https://boards.straightdope.com/u/Dewey_Finn)\ **Post date:** [September 9, 2026, 5:37pm UTC](https://boards.straightdope.com/t/another-waterworld-question-about-the-drinking-water-spoilers/1032914/6 "2026-09-09T17:37:30Z")
Googling, it appears that adding enough water to cover the entire planet to the height of Mount Everest would require several times the amount of water already present on the planet. I think that means that ocean water would still be saline, just not nearly as much? ---
**Author:** ![DrDeth](https://avatars.discourse-cdn.com/v4/letter/d/b487fb/32.png) [@DrDeth](https://boards.straightdope.com/u/DrDeth)\ **Post date:** [September 9, 2026, 5:40pm UTC](https://boards.straightdope.com/t/another-waterworld-question-about-the-drinking-water-spoilers/1032914/7 "2026-09-09T17:40:47Z")
> [@mixdenny](#): > > In the Extended Cut there is a scene where the woman and the girl contribute their urine to the system so they can have more water. Sea water is much easier to filter than urine. > [@mixdenny](#): > > BUT - and this is a big but - would not the extra water around the world have been fresh and thus fairly dilute overall? Well, that water was magical, so we do not know. If all the Ice melted sea level would only rise 70meters/230 feet- and that would only lower the salinity by a small amount. So we do not know where the extra 28000 feet of water came from. I suspect “a wizard did it”, and they asked for salt water. ---
**Author:** ![mixdenny](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mixdenny/32/2962_2.png) [@mixdenny](https://boards.straightdope.com/u/mixdenny)\ **Post date:** [September 9, 2026, 6:24pm UTC](https://boards.straightdope.com/t/another-waterworld-question-about-the-drinking-water-spoilers/1032914/8 "2026-09-09T18:24:55Z")
> [@DrDeth](#): > > Well, that water was magical, so we do not know. If all the Ice melted sea level would only rise 70meters/230 feet- and that would only lower the salinity by a small amount True, but in the film it is as high as Mount Everest. I don’t have any idea where it came from but if it was rained on top of the oceans from the firmament _\*_ There have been solar pools made with varying levels of salinity from dense salt water on the bottom to fresh water on top. They do not intermix. \*I worked with a Morman engineer at NASA. That was his answer to where the biblical flood came from. The firmament. ---
**Author:** ![Darren\_Garrison](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darren_garrison/32/92_2.png) [@Darren\_Garrison](https://boards.straightdope.com/u/Darren_Garrison)\ **Post date:** [September 9, 2026, 6:31pm UTC](https://boards.straightdope.com/t/another-waterworld-question-about-the-drinking-water-spoilers/1032914/9 "2026-09-09T18:31:18Z")
> [@AlsoNamedBort](#): > > If there was additional water added to earth to raise the sea level to Everest (like from a comet) From a few hundred million comets… ---
**Author:** ![Peter\_Morris](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/peter_morris/32/359_2.png) [@Peter\_Morris](https://boards.straightdope.com/u/Peter_Morris)\ **Post date:** [September 9, 2026, 6:41pm UTC](https://boards.straightdope.com/t/another-waterworld-question-about-the-drinking-water-spoilers/1032914/10 "2026-09-09T18:41:23Z")
> [@DrDeth](#): > > If all the Ice melted sea level would only rise 70meters/230 feet How much would sea level rise through thermal expansion if the entire ocean got 1 degree Celsius warmer? Anyone know? What if it was 2 degrees? ---
**Author:** ![Just\_Asking\_Questions](https://avatars.discourse-cdn.com/v4/letter/j/ba9def/32.png) [@Just\_Asking\_Questions](https://boards.straightdope.com/u/Just_Asking_Questions)\ **Post date:** [September 9, 2026, 9:36pm UTC](https://boards.straightdope.com/t/another-waterworld-question-about-the-drinking-water-spoilers/1032914/11 "2026-09-09T21:36:43Z")
> [@Dewey\_Finn](#): > > Unless something caused the land to sink. The weight of all that water. duh! 😉 ---
**Author:** ![crazyjoe](https://avatars.discourse-cdn.com/v4/letter/c/f14d63/32.png) [@crazyjoe](https://boards.straightdope.com/u/crazyjoe)\ **Post date:** [September 10, 2026, 3:04am UTC](https://boards.straightdope.com/t/another-waterworld-question-about-the-drinking-water-spoilers/1032914/12 "2026-09-10T03:04:56Z")
Ships at sea will typically have deslinisation equipment on board to make freshwater from sea water should they need it, and the Valdez definitely had one. ---
**Author:** ![DrDeth](https://avatars.discourse-cdn.com/v4/letter/d/b487fb/32.png) [@DrDeth](https://boards.straightdope.com/u/DrDeth)\ **Post date:** [September 10, 2026, 6:07pm UTC](https://boards.straightdope.com/t/another-waterworld-question-about-the-drinking-water-spoilers/1032914/13 "2026-09-10T18:07:19Z")
Oddly Waterworld was not a flop- per wiki- > _Waterworld_’s reported budget was $172 million, and a total outlay of $235 million once marketing and distribution costs are factored in.[[2]](https://en.wikipedia.org/wiki/Waterworld#cite_note-NY_Times-2) Because of the runaway costs of the production, some critics dubbed it “Fishtar”[[29]](https://en.wikipedia.org/wiki/Waterworld#cite_note-31) and “Kevin’s Gate”,[[30]](https://en.wikipedia.org/wiki/Waterworld#cite_note-32) alluding to the flops _[Ishtar](https://en.wikipedia.org/wiki/Ishtar_(film) "Ishtar (film)")_ and \*[Heaven’s Gate]([https://en.wikipedia.org/wiki/Heaven’s\_Gate\_\(film\)](https://en.wikipedia.org/wiki/Heaven's_Gate_%5C(film%5C)) "Heaven’s Gate (film )")\*. > The film debuted at the box office at No. 1.[[31]](https://en.wikipedia.org/wiki/Waterworld#cite_note-33)[[32]](https://en.wikipedia.org/wiki/Waterworld#cite_note-34) For its first weekend, _Waterworld_ collected a total of $21.6 million.[[33]](https://en.wikipedia.org/wiki/Waterworld#cite_note-35) At the end of its run, the film grossed $88 million at the North American box office, and $176 million overseas, for a worldwide total of $264 million.[[3]](https://en.wikipedia.org/wiki/Waterworld#cite_note-mojo-3)\ > After factoring in home video sales and TV broadcast rights among other revenue streams, it eventually became profitable.[[34]](https://en.wikipedia.org/wiki/Waterworld#cite_note-36)[[35]](https://en.wikipedia.org/wiki/Waterworld#cite_note-BOPerception-37) ---
**Author:** ![ParallelLines](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/parallellines/32/3575_2.png) [@ParallelLines](https://boards.straightdope.com/u/ParallelLines)\ **Post date:** [September 10, 2026, 10:19pm UTC](https://boards.straightdope.com/t/another-waterworld-question-about-the-drinking-water-spoilers/1032914/14 "2026-09-10T22:19:04Z")
The “extended universe” for Waterworld, mostly a limited run of comics and video games indicate that a lot of the water came from comets or other outside sources, not just the melting icecaps, and includes a society of domed scientists doing genetic engineering leading to icthyus sapiens. But yeah, it’s still basically just a magic conceit anyway. My very _limited_ understanding of various saline converters (mostly from online research, commercial plants, and homesteading/survival works) indicates that outside the most basic boil/condense options, that it’s finicky and or dependent on consumables. Most of which you’d expect to be used up/in short supply in the atolls and even among the smokers. It’s been quite a while since the deluge started including several decades of hybrid land dwellers and increasing fleets/atolls of displaced peoples. One implication of the movie is that we may be seeing an end to humanity - so many atolls destroyed, genetic bottlenecks, difficulty of finding new/different people across the endless water. Things are just getting worse with the various travelers getting more isolated, more crazy, and flat out fewer. No regular trade (and little TO trade) between settlements. And of course, it leaves out the little thing (also in the EU) as to why Enola has no parents - they died from “the black bone plague” which was a big part of the early drafts, taking out entire fleets and atolls as well. So, yeah, even if the Mariner brings in everyone he finds to Dryland, the unmodified human species may be heading past the brink already. ---
**Author:** ![Just\_Asking\_Questions](https://avatars.discourse-cdn.com/v4/letter/j/ba9def/32.png) [@Just\_Asking\_Questions](https://boards.straightdope.com/u/Just_Asking_Questions)\ **Post date:** [September 11, 2026, 2:35am UTC](https://boards.straightdope.com/t/another-waterworld-question-about-the-drinking-water-spoilers/1032914/15 "2026-09-11T02:35:44Z")
Of course, if a comet with 5 times the volume of all the water currently in the world hit the earth, the rising sea levels would be the least of our worries. ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [September 11, 2026, 3:39am UTC](https://boards.straightdope.com/t/another-waterworld-question-about-the-drinking-water-spoilers/1032914/16 "2026-09-11T03:39:49Z")
The (rapidly) rising steam levels would par-cook everything organic everywhere. ---
**Author:** ![Lucas\_Jackson](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lucas_jackson/32/303_2.png) [@Lucas\_Jackson](https://boards.straightdope.com/u/Lucas_Jackson)\ **Post date:** [September 12, 2026, 8:20pm UTC](https://boards.straightdope.com/t/another-waterworld-question-about-the-drinking-water-spoilers/1032914/17 "2026-09-12T20:20:47Z")
> [@Just\_Asking\_Questions](#): > > Of course, if a comet with 5 times the volume of all the water currently in the world hit the earth, the rising sea levels would be the least of our worries. Came here to say just that. I’ve read that the Romans could desalinate seawater while at sea by catching boiled steam in sponges. ---
**Author:** ![echoreply](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/echoreply/32/3641_2.png) [@echoreply](https://boards.straightdope.com/u/echoreply)\ **Post date:** [September 12, 2026, 11:07pm UTC](https://boards.straightdope.com/t/another-waterworld-question-about-the-drinking-water-spoilers/1032914/18 "2026-09-12T23:07:18Z")
> [@Just\_Asking\_Questions](#): > > if a comet with 5 times the volume of all the water currently in the world hit the earth, the rising sea levels would be the least of our worries It doesn’t hit all at once. The comets all get trapped in orbit and slowly melt and rain down over a few years. Any other explanation would just be silly. So, we’ve added all of this extra water to the planet and raised sea level to 28,000 feet above the old sea level. How does all of that extra mass change the gravity? Are things just a little bit heavier, or a lot heavier? What about atmospheric pressure? Air is pretty thin at 28,000 feet, but any extra gravity, plus all that water displacing the low down air will change that, but I don’t have any good sense of how. ---
**Author:** ![markn\_1](https://avatars.discourse-cdn.com/v4/letter/m/f9ae1b/32.png) [@markn\_1](https://boards.straightdope.com/u/markn_1)\ **Post date:** [September 13, 2026, 12:11am UTC](https://boards.straightdope.com/t/another-waterworld-question-about-the-drinking-water-spoilers/1032914/19 "2026-09-13T00:11:19Z")
> [@echoreply](#): > > How does all of that extra mass change the gravity? A shell of water 8000 miles in diameter and 28,000 feet thick has a volume of just about 1 billion cubic miles and a mass of 4.5 x 1018 tonnes. That is just 0.07% of the current mass of the Earth, and would increase objects’ weight by that ratio. But floating on the water 28,000 feet above the current surface of the Earth would DECREASE your weight by about 0.26%, so the overall effect would be that objects on Waterworld would weigh 0.19% LESS than on Earth today. If you weigh 150 pounds today, you’d weigh 149.7 pounds on Waterworld. Incidentally, a billion cubic miles is about the volume of 8 million very large comets. and comets are not 100% water. ---
**Author:** ![Just\_Asking\_Questions](https://avatars.discourse-cdn.com/v4/letter/j/ba9def/32.png) [@Just\_Asking\_Questions](https://boards.straightdope.com/u/Just_Asking_Questions)\ **Post date:** [September 13, 2026, 3:08am UTC](https://boards.straightdope.com/t/another-waterworld-question-about-the-drinking-water-spoilers/1032914/20 "2026-09-13T03:08:15Z")
> [@echoreply](#): > > but I don’t have any good sense of how. The same amount of air is displaced over a larger volume, because the inner surface of the atmosphere is 28K feet higher. So, the air pressure would be lower. But the percentage change is small, so the sea level air pressure would probably be close to what it is now.