Hacker News Reader

A lot of places "cycle" water via the rain cycle and often above-ground reservoirs and rivers, which is potentially a huge problem if that rain and/or those reservoirs or waterways are suddenly affected by radioactive fallout or less dramatic factors, like droughts.

So it's a absolutely a real problem.

Closing that cycle in any way that'd even remotely remove contamination would be a massive amount of work.

But more than that, even though many - certainly not all - sewage treatment plants output water that is clean enough for consumption, the bigger problem is psychological and political. No politician wants to be on the front page for having ok'd pumping "toilet water" into peoples drinking supply.

So you're right, in a way: It's "weird". But at the same time, it's a deeply ingrained disgust that has a rational basis given how many disastrous diseases have historically spread via fecal contamination of drinking water, for example.

Depends on how you define "consumption". If you include agricultural and industrial use, then a lot comes from aquifers. An no those aren't used in short, local cycles; a lot of (polluted) water is moved overland (in rivers) to locations and distributed far and wide. I don't have any numbers at hand on sources of domestic consumption for major cities across the world, but I do know that most cities in Europe rely on a combination of surface and aquifer water to fill their treatment plants and supply systems. When you open the tap, it's not the same water you flushed down the drain when you showered last week. (I've worked on water modeling but not on a fine enough scale to be able to remember an exact answer to your question).

But, when talking 'water shortage', the image the media paints is inaccurate. The California water shortages are not a (representative) example of the long term problems. A more realistic (but abstract, which is why it doesn't make a nice story in the newspaper...) scenario is that of drought in less developed countries. Climate change makes summer hotter and monsoons more intense. Land is degraded due to lack of planting when plants die off in summer heat. Rain in winter then flushes away because there is nothing to hold to water (soil erosion). Crops fail, war erupts. Wars in Africa or Asia influence the rest of the world as well, but yeah that's not the same story as 'water shortage! Your tap in California will stop working!'. And if Africa or Asia are too abstract - southern Europe faces the same problems, albeit in a less severe form (and with better options to control).

In the aggregate, what you say can be said of any resource. "We don't have an oil problem, just the energy problem of converting airborne carbon into a liquid combustible form." When I put it like that, it's obviously a ridiculous reduction; and while the water issue isn't prima facie ridiculous when phrased like you do, the underlying dynamic is the same. It's true that we have no less water than 10k years ago; but it's in different places, is put on land through different forces, is contaminated with other chemicals making it unsuitable for direct use.

Use of sewage for potable water is still pretty rare.

New York City famously has tunnels up into the mountains for most of their water supply. One of them was featured in Die Hard III, where it was used (while under construction and dry) to smuggle dump trucks full of gold.

Chicago draws water from Lake Michigan and discharges sewage into (artificial) headwaters of the Mississippi.

Folks in upstate New York hate NYC for the water supply. Much of the economy of the "southern tier" region is crippled by the requirement to keep water quality pristine (NYC being one of few cities that doesn't significantly process incoming water), and to manage water flows (including that of the Delaware River itself) to optimize the reservoirs, at the expense of fisheries and stuff.

Mind, having the Hudson horribly polluted from previous industrial activity in regions like Schenectady/Albany/Troy isn't all that great, either.

Even in areas of plentiful cheap water, it takes electricity to make chlorine for sanitary treatment, and it takes relatively much larger amounts of energy to successfully process sewage, so when the grid inevitably goes down, war or not, there will be lush supplies of irrigation grade water that will sicken or kill anyone who drinks it.

Food equals water for all practical purposes so higher water costs equals higher food costs. Right when the transportation infrastructure is likely to be overloaded...

Globally, the planet won't run out, but local populations might.

There are many factors influencing availability. Salinity, as you mention, and water that's "locked up" in other organisms, or in the geology. And don't forget power/political structures that limit access. Then there's cleanliness: ensuring that water is safe is a complex problem requiring infrastructure, energy, transportation, education, governance, etc.

Increasing temperature will evaporate more water, forcing us to implement new ways to harvest it. If locations of water harvesting become increasingly disparate, then we are faced with an increasingly thorny logistics problem: transporting the water to where it's needed.

With these practical factors, accessible clean water may indeed become limited for an increasing percentage of the population.

I don't know about the rest of the US, but I know in the midwest a pretty decent portion of the population get their water supply from the Ogallala Aquifer (https://en.wikipedia.org/wiki/Ogallala_Aquifer). According to that link it's as much as 82% of the High Plains population.

Energy supply would seem to be a key to survivial in a nuclear wintr. Not just in water supply but food production (artifical light) and heating. Although use of coal and oil may be simpler than renewables.

> have to pay a greater percentage of our salaries for water

That would be ironic, because 'salary' was originally money given to soldiers to buy salt, not get rid of it.