When there are many water turrets in a world the water turrets mod uses 14 ms of processing per frame, this could be caused by many of this firing simultaneously

Yes. I know the code isn't optimal! I also know how to improve it (some late version of Factorio 0.18 added features that should drastically increase performance), but that would involve a major code rework, with potential pitfalls where I could add new bugs. So I'll see that I can get to work on it soon, but it may still take a while. (Adopted too many mods, now I have too many mods that need to be updated for Factorio 1.0, all at the same time … )

Working at it, looks quite promising so far! :-D

Please try out version 1.0.0! :-)

Seems, still low.

Seems, still low.

Do you have a current save from a real game with the latest version of Water Turrets? In my tests, I've seen UPS load drop significantly, but of course that may not be representative for a bigger setup.

Made some more optimizations in version 1.0.2. While testing on a map with about 200 turrets responding to quickly spreading fire from Flammable Oils, I saw a massive improvement in comparison to 1.0.1. I'd be glad if you'd try out the new version and see if that's also the case in your game. :-)