It’s generally safe to drink tap water in Costa Rica, except in the most rural and undeveloped parts of the country. However, if you prefer to be cautious, buying bottled water is your best bet. If you have the means, vigorous boiling for one minute is the most effective means of water purification. At altitudes greater than 2000m, boil for three minutes. Another option is to disinfect water with iodine pills: add 2% tincture of iodine to 1L of water (five drops to clear water, 10 drops to cloudy water) and let stand for 30 minutes. If the water is cold, longer times may be required. Alternatively, carry a SteriPen that destroys most bacteria, viruses and protozoa with UV light.