Understanding Sanitation

SANITATION

I had a hard time finding this.
Lets see if my poor english let me explain this.

Sanitation works for the city where you build it, not province. Thats all.

BUT

There are some upgrades to sanitation that gives them the ability to give sanitation to other citys (It says in the description, +1 to all citys in the province or something so).

Use the TOOLTIPS (place the cursor over the green/red fountains icons) to see how much sanitation has each town.
For example, if u dont have sanitation buildings in a town, but you dont have buildings that produce squalor, you will see:

sanitation = 0 (This is the total sanitation u have in ur city)
squalor = 0 (the total misery)
total sanitation = 0 (The sanitation still free after resting the sanitation with the squalor).

So:
If you have a city with a +4 sanitation building, and a + 3 squalor building, then:

sanitation = 4 (the total sanitation)
squalor = 3 (the total squalor in the city)
total sanitation = 1 (the sanitation still free).

Then you can still build a building wich gives +1 squalor. If it gives more than 1, then you will eventually get a plague. The fountain symbol will turn red.

If that +4 sanitation building gives that plus +2 sanitation to all citys (in the province), our city will have the same numbers... but the other citys in the province will get a +2 sanitation each one for free. Wich is great...

Also, you must know this:
At Citys (the main settlement of each province): your sanitation buildings will NOT give the "+x" plus to other regions. Not matter if you upgrade them. The upgrades dont give that,

In Towns is where the upgrades to sanitation buildings give you the "+x" plus to other settlements.

So sanitation buildings at citys will not give you pluses to other towns.
But if you build sanitation buildings in Towns, you will eventually get those pluses (if you upgrade them)

EDIT: That is really not true. As i have played more factions, with some of them you can build sanitation buildings in your MAIN city that affect other regions of the Province (for example, with Romans). With other factions, you cant (as described in the guide).

Hope this helps.