Water in restaurants

Just musing here on the topic of bottled waters. Some restaurants are now refusing to serve tap water and insist that you pay for bottled. I always thought that this was illegal, but apparently, that is not the case. In the case of a restaurant which I visited very recently indeed, the bottled water that arrives, costing £3 for 0.5ltr, is in fact tap water anyway. If your bottle says "Table Water" or "Pure Water" instead of "Mineral Water", then what they mean is "Tap Water". Sometimes it will be straight from the tap and in other cases it may have gone through a reverse osmosis purifier.

I buy reverse osmosis water from the garden centre to water some exotic, lime-intolerant plants of mine. It costs £2.50 for 5 gallons.