Short answer: yes, if you are willing to take a risk.
Long answer: You should be able to follow this link to the EPA's website for more detailed explanation. Looks like some contaminants (coliforms - ie, bacteria) are found in the water system with some frequency in most of Puerto Rico's water systems.
http://oaspub.epa.gov/enviro/sdw_query_v2.get_list?wsys_name=&fac_search=fac_beginning&fac_county=&pop_serv=500&pop_serv=3300&pop_serv=10000&pop_serv=100000&pop_serv=100001&sys_status=active&pop_serv=&wsys_id=&fac_state=PR&last_fac_name=&page=1&query_results=&total_rows_found=
Added: Puerto Rico water system is similar to the states. So, if you drink water from your state then their is not going to be any problem with the water from PR.
Horses need access to drinkable water daily. Horses will not eat if they do not have water. It does not need to be fresh from the tap daily, but needs to be refilled daily and dumped out and washed at least monthly.
Yes, tap water is fresh, because it is drinkable and not salty. That is what is meant by fresh water.
the ocean or sea
Tap water, Spring water and Fresh water
About 2.59% of Earth's total water supplies is drinkable water
The majority of Earth's fresh water is locked away in glaciers, ice caps, and underground aquifers, making it inaccessible for drinking. Additionally, pollution and contamination have further reduced the amount of drinkable fresh water available for human consumption.
Definitely yes. Even tapped water is drinkable in Tehran & most cities!
Technically, all the water on the Earth is drinkable. Desalination plants are constantly modifying salt water into fresh water.
Only about 1.7% of earths water is drinkable fresh water, so conserve it! Most of the fresh water is found in glaciers
Water on Earth is unevenly distrbute throughout the world. For example,in some poorer countries poor people don't have access to clean and fresh water either have to walk a long way to get drinkable water or they just use the water that is available to drink and wash with;dirty,polluted water
Fresh and salt water are very different for one key reason, fresh water doesn't contain salt and salt water obviously does. There are different flora and fauna in fresh and salt water for this reason.
Well, yes, horses should always have access to fresh water.