Awesome, that was one of my favorite games ever! So generally the reason it’s advised not to use fluid sim in games is because while your rig can handle it pretty well consistently, not all or even most users will ever be able to, though as a hobby project that might not be your concern.
On to what I learned. The fluid simulation uses a grid system to determine where the water particles begin and how they interact, so they are locked to this grid initially in the examples. This means it’s a bit harder to just determine the shape unless you can interact with the grid (though there is no documentation for this). For reference most users I had recognize either accepted with the fluid’s base shape like this user or poured the fluid via the hose preset if you require it in 3D.
I believe the first method with the 2D pool would work best in your use case, though it will end up changing your landscape in that regard.
Extra info for other users:
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