water filter recommendation?

[jesm]

There is a wide variety of water filters. Many, cartridge type, 150-250 pesos, only remove sediments, i.e. Physical properties like sand and some chemicals depending on filter size and type. These clean the water somewhat but anything living is still there and it is these microbial matter that sickens you.
There are a number of solutions to much of the microbial problem, most involve reverse osmosis membranes or ultraviolet lamps, which is what we use. Home Depot in Leon have several type of sediment filters and can order RO or UV systems by GE Water. There is a supplier in Guadalajara Aqua-tec that builds household systems and will ship to GTO. Small household systems cost around 5000 pesos.
I worked in the water utility industry for over 30 years. If you use a decent sediment filter then expose water to direct UV light, it is perfectly safe to drink. Otherwise, no 100% guarantees for any water, anywhere.