You will not get complimentary drinking water in a restaurant and people do not offer you water from their kitchen sinks. As a result you will have to buy it. In a restaurant it is part of your order. They will ask you if you would like “sparkling” or “still”, or they may say with or without “gas”. It may be pricier than beer and you can bet on the glass being much smaller. If you would like “ice” you will have to ask for it, and they may say “no”.
To save a little on your outings or at your hotel you may want to buy the quart bottles at the grocery store or beverage mart. Don’t be in a hurry because the selection is broad and not only do you have to decide on the gas, but also the mineral levels. I bought the one with the picture of a baby, I just figured I couldn’t go wrong. If you are on a low sodium diet or have a sensitive stomach I would suggest taking some time to look into this before your trip. Also, bring a water bottle you can carry and add the cost of drinking water to your dining budget. Happy travels !