Sadly, years and years on a pipe dream, and very little known about the costs of water, that is "free".
Thirst is not the issue, neither is capacity it seems, because (at less cost) these could have been solved by now, it's profit; especially since 75% of the water is slated to grow cucumbers in the Karpas by an ever growing population of "Turks" from the mainland.
What of water desalination? What of water conservation? What of the upkeep to existing infrastructure where it's reported that 40% of the clean drinking water is lost from leaking pipes. Indeed, the 'new' pipes will not leak, but for how long (who will build them); and then? When is also a good question, too...
...but it is a little late for all that. In the realpolitik of things, Erdogan needs to score, now. What with the situation as it is, Cypriots are badly served by the efforts Turkey has made. So too, Turkey's reputation. In affect, it reflects badly on the occupation regime with what it has demonstrated as a partner (as "Turks", and as Cypriots). And at this moment, no one is drinking the water yet, thus the water has no real value except political, even the point of transfer is under dispute.
Frankly, I think that he (Erdogan,) will "gift" the water to the Republic, to own and to manage, and in the process, recognise Cypriots as Cypriots, ridding himself of the "Turks" who represent a burden to him by being unable to sustain themselves, promoting a sea-change of world opinion toward Turkey, gaining from the recognition and respect of Cypriots, a new ally, as well the possibility of better relations with Greece, Israel (and Egypt), and the EU.