Duncan's bath has a flat base and vertical sides. It can be filled completely from the hot tap in 15 minutes or from the cold tap in 10 minutes. Its capacity is 360 litres. When preparing a bath, Duncan's habit is to run both taps together for 1½ minutes, before turning off the cold tap. He turns the hot tap off when the bath is ¾ full, then leaves the water for a while to cool down to a suitable temperature before he climbs in.