Watermills

Can someone please explain the concept of these watermills you get with the gems?

I have 3 of them yet somehow I "run out of water!"I thought they were "unlimited" water supply? Am I wrong? It is possible, I was wrong before back in 1977.

the watermills themselves do not run out of water. a regular well only has so many units of water, once its exhausted, you have to rebuild the well. a watermill is unlimited an never runs out of water. however, depending on the number of other buildings you have using water, you may consume water faster than your three watermills can replace it. there are a few calculators in the CEO Guide List that can help you determine what your overall consumption is and how many wells you need.

Remember, you can improve the rate at which you obtain by upgrading the watermills instead of building more.

Watermills supplement your water production but in most cases will not fully make up for water wells. They are more helpful when leveled up and buffed since you don't have to rebuild them like you do the wells. I have 5 at the moment. All at level 2 and above and still need about 30 wells to have a water surplus.

The watermills do produce unlimited amounts of water. It's just that your need of water (for breweries, bakeries and stables) mostly likely exceeds in what your watermills can produce.

What level are each of your watermills? How many and at what level are your breweries, bakeries and stables?
For every level of a brewery, you need 1 well. For bakeries and stables, you need 2 each.

Take me for example, I have 3 bakeries and breweries at level 3 and 2 stables (one at level 1, the other at level 2). That means I need 35 wells or 12 watermills at level 3.

i have 18 x lvl 4 watermills. that equals to 72 x lvl 1 wells that i never need to replace. it also saves on the population that the wells would've taken up. i only build water wells when i'm looking for a huge boost in my supply.