This story contains spoilers about The Martian's plot.

Andy Weir may not have many regrets about his bestselling novel The Martian, especially given that it opens as a Ridley Scott-directed, Matt Damon-starring, space-science-boosting movie later this week.

But if he had to write the whole thing over again, the author told Mashable at a preview screening of the movie Monday, he would include some of the Mars-based science that has emerged in recent years — including that whole liquid water thing.

But because liquid water is present on the red planet only in small and extremely salty amounts, it wouldn't have been particularly helpful for Mark Watney, the botanist who becomes trapped on Mars in Weir's book. Watney would still have to painstakingly make his own water, as he does in the book and the movie by (explosively, dangerously) setting fire to hydrazine.

Even though NASA's liquid water news had only just been announced hours earlier, Weir knew exactly how he'd have use it in the book. Martian water would be a hindrance to Watney, not a help.

"I absolutely would include the briny water," Weir said. "I'd have put it in the Schiaparelli crater."

Readers of the book will remember that this is the crater that holds the Mars Ascent Vehicle (MAV) that lifts Watney off planet. The astronaut has to drive a vast distance to get there, and when he arrives, he suffers a rover rollover at the edge of the crater.

Instead of that rollover being the result of poor driving, Weir said he would have written it so that the rover gets trapped in the sudden flow of wet sand that we now know to be a seasonal occurrence on Mars.

"I like the irony of that," said Weir. Watney would have had so much trouble securing his drinking water earlier in the book, then been brought down by undrinkable streams of the stuff.

The movie version of Weir's book reportedly would have been different as well, if director Scott had been able to incorporate the new water discovery into the film.

“He would've found the edge of a glacier, definitely. It would be fascinating,” Scott told the New York Times Monday. “But then I would’ve lost a great sequence. He has to make water, and the steaming device, and put up the plastic tents, which creates the humidity, which grows the plants, which is the most basic form of irrigation. They still do it in Spain that way.”

So much for the "bring Watney a straw" meme tweeted out Monday by the Martian movie's account — something that one NASA systems engineer immediately advised against.

@MartianMovie Watney noooooo, don’t drink the Mars water. — Bobak Ferdowsi (@tweetsoutloud) September 28, 2015

As it stands, of course, any dramatic plot point involving Martian water will have to wait until a sequel — something that Weir, at present, is declining to write.