However, Paraguay (along with Argentina, Uruguay, and Chile) has its fair share of safe, drinkable tap water. It is considered safe to drink the tap water in Asunción (the capital) and Ciudad del Este (second largest city). Once you venture outside the cities, though, the water is no longer treated and thus becomes unsafe to drink.
I found out quite by accident that Asunción's drinking water is safe. After a few weeks, I noticed that my house mother filled up the water pitchers directly from the sink and put them in the fridge. She did not boil the water, put in iodine tablets, or otherwise filter the water in any way. Since I had already been drinking copious amounts of water without getting sick I reasoned that it must be safe. My Frodor's South America travel guide and various websites confirmed it.
Safe, drinkable tap water makes everything--from cooking to washing fruits and vegetables to enjoying a refreshing glass of water--easier. It's great not having to worry if the ice in a drink at a restaurant is safe or if lettuce was washed in dirty water.