Desalination is sufficiently cheap to not be a material problem for US consumers (or other developed countries). State-of-the-art desalination plants in Israel are fulfilling contracts at ~$0.40/m^3 [1] and the per-capita water usage in the US is ~1200 m^3/yr [2]. Even if we assumed that the current price of water is $0, this would only amount to a $480/yr increase in expenditure per American which would constitute a one-time 1.4% increase of yearly expenditure for the median American. Note that this accounts for all agricultural production in the US; if we consider just water for domestic use such as drinking, bathing, and watering the lawn the average person only uses ~100 m^3/yr [3] which is ~$40/yr which is within reach of every household. This also assumes that increased water prices will not result in changes to water usage which is very doable as the US uses ~3-4x as much water per capita as other peer countries such as France and Germany and 10x the water of Israel which already needed to adjust to a regime of desalination water prices.

All in all, considered merely in economic terms, desalination is a perfectly viable solution to the water crisis in developed countries and would incur at most a relatively minor economic impact by this analysis. Note that this does not necessarily apply to developing countries where a $40/yr expenditure increase could be catastrophic. I am also not making any statement about non-economic considerations such as possible effects on the environment that may occur as a result of the need for increased power generation for mass desalination.

[1] https://www.globenewswire.com/news-release/2020/05/27/203950...

[2] https://www.statista.com/statistics/263156/water-consumption...

[3] https://www.epa.gov/watersense/statistics-and-facts