[londons_explore]

London (UK) has deliberately low water pressures because the pipe network has a lot of leaks, and the lower the pressure the less water leaks out.

It's low enough that some appliances like dishwashers and washing machines give 'water supply' errors unless you run them overnight. Some houses use pressure boosting pumps to get water to the top floor.

Apparently fixing the leaks is expensive and it's free to just lower the pressure and pass the problem onto householders.

[Scoundreller]

A kinda rule of thumb is that municipal water systems lose 10% of their water through various small leaks. Water is generally cheap and your bill is more for maintaining the capital cost itself rather than gathering/processing the water.

I also use this analogy for smuggling and the resources spent trying to stop it: if 10% gets lost/intercepted/“leaked”, the smugglers just produce and send 11% more and demand is met. You can change the numbers but it doesn’t change the result.

[PaulDavisThe1st]

Now do that math for the US southwest, where water is ridiculously cheap and also severely limited ....

[kortilla]

It’s not severely limited, that’s why it’s cheap even ignoring people with huge water grants and purchasing on the open market.

Using the entire annual flow of the Colorado river doesn’t mean it’s severely limited. It just means society isn’t stupid and will use the excess to fill sunny deserts to grow crops.

As long as there are crops grown anywhere between Phoenix and LA, water isn’t severely limited.

[PaulDavisThe1st]

> It’s not severely limited, that’s why it’s cheap

This is false.

Most western states associate water rights with land ownership. The marginal cost of a unit of water for a user with their own well is close to zero (wells do require electricity and maintanance, but these costs are generally very small).

However, the existence of those water rights (e.g. "this 5 acre parcel comes with 3 acre-feet of water") has nothing to do with whether the water is actually available, and increasingly in many parts of the southwest, it is not.

"Severely limited" in my book means that water usage could not increase by 50%. Fairly sure this condition applies to more or less the entire US southwest.

[kortilla]

That’s still not severely limited and that definition is idiotic. That’s like saying the copper market is severely limited just because all of the supply eventually clears at some price.

It’s all being used because there is enough farmland and sun to absorb it. Cut out the farming and the remaining usage could easily grow several hundred percent.

People grow absolutely ridiculous shit in southwest Arizona because water is so cheap and is not “severely limited” by any notional definition of the term.

The only context in which it looks that way is to people coming from locations that are inundated with water but are land/weather limited.

If you want to see what “severely limited” water looks like. Take a look at Israel.

As long as people can pay $100 for 10,000 gallons of water to fill a pool, there is no severe limit.

[PaulDavisThe1st]

I don't think you understand that a lot of water usage in the southwest is not paid for at all.

In the village where I live in rural New Mexico, at least 30% of the population here have private wells and pay nothing for water at all (other than pump energy costs and well maintanance costs). Ranchers to the south of the village pump their own water and use it to irrigate alfalfa fields without paying anyone anything at all.

The reason water is cheap here is because of the historical and legal situation. If water was managed here as it is east of the Mississippi, where it is considered exclusively a public resource, then water supply systems would be able to charge prices more like those found in the east. But because "water rights" are bound up with "land rights", there is no way currently to do politically-controlled water pricing outside of city water systems.

And yes, agriculture in this part of the world uses 75% or more of all the water that falls or flows through the land, and if that wasn't here, water would not be much of an issue. I advocate locally for changes in how agriculture is done here, and write articles for hyperlocal media here to raise awareness of this issue.

But for now agriculture is here, using water wastefully and substantially, and that means that in effect the water supply is severely limited to the point that local jurisdictions will pay farmers to not use water that they have rights to.

I've lived in Israel (Rehovot). The Negev is a broadly similar climate (though much lower in elevation) as southern New Mexico and northern Israel is very similar to northern New Mexico. The Israelis are world leaders in the use of desalination, an option that makes no real sense for most of the US southwest (southern CA would be the obvious exception). This makes a significant difference to water availability both for agriculture and residential use in Israel.

[rurp]

Yeah we should probably stop subsidizing the heaviest water users. Instead we get high profile efforts that get a lot of attention and only save a token amount of water.

[amanaplanacanal]

I believe the issue is that those water users own the water by right under the legal theory that the first users own it forever. The state could eminent domain it away but then they would have to pay some (probably very high) price for it, and nobody wants to do that. Eventually they are going to have to cough up the money.

[shiroiushi]

So I guess London is just screwed if there's another big fire.

[londons_explore]

By law, houses must be built with fireproof (ie. Brick) walls between them, so a fire will not spread from one house to the next. This gives them a distinctive look [1].

There are no timber frame buildings, not any with flammable roofs like thatch or shingles.

They aren't going to make the mistakes of the great fire again!

It seems to work - I have never seen any fire burn more than one building.

[1]: https://www.reddit.com/r/london/comments/149wg3o/why_do_lond...

[shiroiushi]

Very interesting. Still, you'd think they'd put a little more effort into having a modern, high-pressure plumbing system in their main city.