There’s enough water, especially for bathing. The problem is location. People tend to live where water is available but a low threat. That also means there isn’t a whole lot of water there. Think California. Once these populations start growing however, you get a problem, together with poor water planning and government interventions like what is currently happening in China and California.
But the Saudis and Israelis have overcome these issues, sure it it isn’t cheap, but it’s not impossible, with nuclear power, you can basically desalinate water for practically free forever.
China has a major issue with water. All of their water is polluted, but the government doesn’t want to bring the market to bear so it is literally building waterways from one side of the country to the other, with disastrous results.