I don’t know about power, but Vegas is actually incredibly water efficient. Due to the way the water rights work with the Colorado river, they’re not allowed very much, but it doesn’t “count” if you put it back in. So nearly every drop they use is treated and put back (probably cleaner, tbh). Boggles the brain, but somehow it’s actually a fairly sustainable city. More than any other other major metro, in any event.
Thrilled you asked! So yes: Treatment is always required, but the final destination of the treated water can vary. For instance, in a lot of places they may have municipal water TO a home or business, but that may be discharged to septic, as opposed to the river. Also in a lot of areas, water may be taken out of an underground aquifer (either by private well or a municipality) but when treated it may be discharged into a river or ocean. That can create problems because if you’re near the coast, the empty space in the aquifer may be filled by salt/brackish water that can lead to salinity rises in the aquifer. To solve that some places turn to “ground water recharge”, which is just a fancy way of saying “we built a big well to put it back in the aquifer”.
Increasingly, you’re seeing some places essentially sell their treated water. Santa Rosa CA, for instance, built an entire pipeline that goes from their treatment facility to another municipality to be injected into their groundwater.
So yes, everywhere treats it, but the final destination makes a difference. Las Vegas (or anyone else on the river) only gets credit for what goes back into the river, so any evaporation etc is a problem. It sounds trivial, but there is a reason those other strategies exist. It essentially doubles every pipe, limits where you can park a treatment plant etc. Vegas also does some great grey water re-use. That essentially means it doesn’t go “back” but can get used many many times, limiting the initial draw.
Wastewater is funny because it’s far from rocket science, but the numbers to implement any of it get staggering very quickly.
Wastewater isn’t rocket science. It’s just harder and significantly more important. Every engineering discipline makes fun of the civils, but the fact is none of us are half as critical to modern life as them. Every benefit any of us claim rests on their backs. The flow of electricity is a civil engineering feat, the flow of water to and from our homes, businesses, and farms is a civil engineering feat (and critical to health), as is our transportation networks, our entire constructed environment, and even crazy and weird shit like controlling the location of critical rivers.
Considering they are in a literal desert, they would have to be fairly sustainable to exist in the first place. Not saying it’s not super impressive, my dad lived out there when they were building up a lot of the expanded infrastructure and he has some cool stories about how he saw the desert on the outskirts disappear as they added in all the water and transportation stuff
