One of the lessons that I've learned after having been here in El Salvador for almost two months is about taking water for granted. Living in California, that should never be the case, but, living in California, water is always there from the tap and safe to drink.
El Salvador actually had a fairly decent water system until about 10 years ago when a major earthquake damaged the aqueducts and pipes delivering water and allowed for contamination with sewage or industrial pollutants. Now the water can be hit and miss with periodic interruptions - pipes breaking (we saw the effects of a broken pipe spilling water for two days before being fixed) or power outages which mean no pumps which mean no water. Also, none of the places I've been have hot water unless incidentally warmed in pipes arranged on the roofs.
For drinking water, bottled or bagged water is the rule in the cities. We get ours in five gallon plastic bottles, which doesn't go a long way when you rinse fruit and vegetables before cooking or eating raw. Bottles and empty bags are a significant litter problem here, too.
One irony is that there are rivers and streams all over these mountains and with the downpours when it rains and the rainy season in full swing next month, there is lots of water flowing, polluted as it is.