Water should be the number one priority. Multiple Desalination plants must be established ASAP. These should be included in CPEC, funded by China, to speed up the process. Of course se on BOT basis, after 30 years or else the Water Tanker Mafia is going to pull the funding on the desalination plants, by buying out Sindh Government, which itself is involved in promoting such Mafias.
Whether K4, K5 etc happens or not, Karachi is too big to depend on inland water source.
If Balochistan can threaten to block Karachi's water supply then these political Sindu Desh people will do the same in the near future.
It must be made a law that every housing society, whether run by the Civilians or Retired / On duty Armed forces, must have water supply lines, sewage lines, electric wiring / transmission, roads pavements, other amenities according to international standards.