[xyzzyz]

Agricultural water and municipal drinkable water are two different things. The farm water does not come from the same distribution system as city water. For example, pulling water straight from a river to irrigate farm is agricultural water. Maybe the cost of agricultural water is too low, it probably is at least in some places. However, it is not clear at all that agricultural uses even compete with urban uses. Urban areas take their water from very specific locations, and a farmer using water from some other source does not necessarily result in any less water available in the location the urban water is drawn from. In many (probably most) cases, if farmers won’t use the water, nobody will, because there is no way to get it from where it is to where it is needed.

People tend to think about water distribution similarly to electricity, which is completely wrong. With electricity, there is one all-encompassing grid that everyone uses, and if some people use more of it, there is less of it available for others. Water is not like that: it is as if there were thousands of independent grids that cannot be easily connected, because pumping water over large distances is most often prohibitively expensive.

[abeppu]

Drawing the distinction between municipal drinkable water and agricultural water is useful. But in the Central Valley, my understanding is that farms are heavily reliant on well water, and their use pushes the level of the aquifer down in a way that disrupts the supply of drinking water. In some cases, there is a direct competition between agricultural use and residential use, but not necessarily "urban" use.

https://www.theguardian.com/environment/2020/feb/28/californ...

[ashtonkem]

Well water is even harder to regulate, because anyone can sink their own well whenever they want to. There’s no state owned tap to which you can attach a meter and send a bill for.

[Retric]

Oddly a large majority of the state actually drains into San Francisco Bay Area.

~99% of free flowing water in CA would evaporate or dump in a tiny number of rivers which are tapped for urban water. The only reason many of these watersheds appear separate is 100% of the water is removed long before it enters the ocean. The Kern River being a great example that used to dump into the San Joaquin River but none of that water flows into the ocean today.

https://en.wikipedia.org/wiki/List_of_rivers_of_California

PS: Wells generally tap flowing water even if it’s simply not obvious that’s what’s going on. Basically, the ground can only hold so much water and it normally absorbs excess from rain which eventually flows into streams etc.

[rsj_hn]

> Wells generally tap flowing water even if it’s simply not obvious that’s what’s going on. Basically, the ground can only hold so much water and it normally absorbs excess from rain which eventually flows into streams etc.

This was news to me, thank you. Do you have a source for further reading?

[zdkl]

This ought to be a decent starting point for vocabulary and mechanisms: https://en.wikipedia.org/wiki/Aquifer

[dragonwriter]

> The farm water does not come from the same distribution system as city water.

Yes, it does, ultimately, in very large part. It may not traverse all of the same infrastructure, but it comes from the same sources, which have limited capacity. (And, in California, quite a lot of both urban and agricultural water is delivered by either the California State Water Project or the federal Central Valley Project, and an additional fraction of both urban and agricultural water is from sources downstream from the diversions for those water projects, and thus competes directly with them.)

> However, it is not clear at all that agricultural uses even compete with urban uses.

Yes, its quite clear that they do compete quite directly in California.

> People tend to think about water distribution similarly to electricity, which is completely wrong. With electricity, there is one all-encompassing grid that everyone uses, and if some people use more of it

In California, water is very much like that. Even the sources that seem separate (“I have my own well”) tap into sources (aquifers in the case of wells) shared with, and thus competing with, other uses.

> it is as if there were thousands of independent grids that cannot be easily connected

It’s really not like that all in California, especially outside of certain parts of rural Northern California: the vast majority of both the urban and agricultural parts of the rest of the state are dependent on the two big water projects and/or Colorado River water.

[nonameiguess]

Excellent comment by dragonwriter. Unfortunately, you're wrong about California, even if what you write is true in most places. You can read more about the history of water in Los Angeles here: https://waterforla.com/water/history/

Most today comes from the State Water Project, which pumps all the way from northern California where the Sierra Nevadas drain into rivers and this is the principle source for both Los Angeles and for the Central Valley. Los Angeles also still gets some from the Colorado River pumped across the Mojave, but this is arguably even more insane as it feeds four major metros in Los Angeles, San Diego, Las Vegas, and Phoenix, none of which have their own local water sources to sustain a large city.

LA basin was a pretty terrible place to put the country's second largest metro. LA did originally get its water from local groundwater basins, but those tapped out when the population was still around 6,000. It was solved by building the original Los Angeles aqueduct to pump all the way from Owens Valley. What other city can say its most famous street is named after a water engineer?

[missedthecue]

It's worth noting that in addition to what you said, Californian farms also recycle fracking waste water, something residential systems do not.

[kwillets]

You're not from here, are you?