Don’t drink tap water. Bottled water is available everywhere and is very cheap.
On that note; always keep yourself hydrated. Dehydration is one of the most common and easily avoided forms of discomfort faced by travellers in hot climates. You will need need to drink much more water than usual to stay hydrated so it’s handy that drinks of all varieties are so cheap and readily available. Pouches of electrolyte to pour into bottled water can also be purchased in many places, these are good for replenishing salts and minerals lost through sweat and help prevent dehydration – Gatorade is also good for this if you can’t get electrolytes.