The invention relates to a dental unit and a method for feeding water to instruments and/or to other water outlet points of a dental unit. The object of the invention is to enable keeping pressure of the water lines of a dental unit essentially stable, especially also when the relatively stable pressure typical for public water systems cannot be taken advantage of because of potential backflow of water contaminated at the point of use to the public water system. According to the invention there is arranged a pressure chamber (12) to the feed water line (10) of a dental unit, the said pressure chamber (12) being arranged in functional connection with pressure control means (14, 15), and upstream of the said pressure chamber (12) a pump (13), which is arranged to be able to pump water to the said pressure chamber (12) also when it is pressurized.
