Indeed an excellent point, but there are many mitigating factors that might resolve that problem. 1. Reduced water diversion. If there were mass desalination,

Indeed an excellent point, but there are many mitigating factors that might resolve that problem. 1. Reduced water diversion. If there were mass desalination, the places closer to the shore would have access to a substitute water supply which would reduce their need for water in your water source. This would likely result in having more of the water source available to your city. 2. Water usage. The vast majority of water people "use" is actually in the form of food. Unless your home is growing a vast quantity of crops in the dry US southwest, it is highly unlikely that you are actually depleting your water source unless it is being diverted to farming. If your city is farming, then the farms will relocate after the water supply is dried up to a place where desalinated water is more accessible. Once this occurs the newly relocated farms will be able to produce in their new location and it is likely that your city will no longer be net depleting the water source. So, food continues to be produced, but elsewhere, and your city now has water. 3. Pipelines are cheap. Pipelines are actually quite cheap based on my research. Here is a 15 year old paper which estimates the price of water pipelines to be ~$0.06/m^3 per 100 km [1]. At 1000 miles which is ~1600 km, that would only be an extra $1.00/m^3 raising your costs to $1.50/m^3 over your existing costs for both desalination and piping. For an average American that would be ~$1800/yr or ~4.2% increase in yearly expenditure. 4. Water embodiment. Again, the vast majority of water people "use" is in the form of food. That means that most of the water you "use" will likely be used on farms which will likely be wherever water is cheap. This reduces the direct costs to you. It also means that you do not actually need a very large source of pure water to support a city since most of the water being imported is "food" which is a volumetrically and price efficient means of "importing water". It is quite likely that you would need at most a modest pipeline or possibly even be able to ship the pure water some other means without being too costly. 5. Moving. If water actually becomes unavailable then your city would become inhospitable much like random wilderness and people would leave rather than die of thirst. This may be unpalatable to you or others in your city if you like where you live, but it is almost assuredly what would happen if no other solution is possible and would "resolve" the problem. Essentially, the problem is solvable, but like any other change may require tradeoffs of money or lifestyle. The less change in lifestyle you want the more money it would cost, but even essentially zero lifestyle change seems quite feasible for the average American at a relatively modest cost. [1] https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2004WR003749 https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/200...