Together, tax and tip add 25–35 per cent to restaurant bills. SF follows the US tipping standard: 20 –25 per cent is generous; 15 per cent is the minimum, unless something went horribly wrong with the ser vice you received. More SF restaurants are now charging a flat 20 per cent ser vice fee, especially for large par ties, even though diners may balk at having tipping decisions made for them. Restaurants argue that the flat fee helps guarantee a living wage to staff in the notoriously pricey Bay Area. Some restaurants tack on a 4 per cent surcharge to cover the cost of providing health care to employees, as required by SF law.