A method of concentrating waste liquid from a plate-making process of a planographic printing plate, the method comprising: a plate-making processing step of subjecting a negative-type photosensitive planographic printing plate precursor, having a radical polymerizable image recording layer on a support, after exposure simultaneously to a development process and a desensitization process using a developer liquid in a single development processing bath of an automatic developing machine that develops the negative-type photosensitive planographic printing plate precursor after exposure, wherein the developer liquid contains from 1% by mass to 10% by mass, based on the total amount of the developer liquid, of a surfactant having a phenyl group or a naphthyl group and at least either an ethylene oxide group or a propylene oxide group, and has a content of an organic solvent having a boiling point in a range of from 100°C to 300°C of 2% by mass or less, based on the total amount of the developer liquid, and substantially does not contain an organic solvent having a boiling point lower than 100°C or higher than 300°C; a waste liquid concentrating step of evaporatively concentrating plate-making process waste liquid produced by the plate-making processing step using a waste liquid concentrating apparatus such that a ratio of a volume of the plate-making process waste liquid after concentration to a volume of the plate-making process waste liquid before concentration is from 1/2 to 1/10; and a reclaimed water producing step of producing reclaimed water by condensing water vapor separated in the waste liquid concentrating step, wherein a pH of the developer liquid is from 6 to 10, wherein a developer liquid is excluded which includes a surfactant and a hydroxide of an alkali metal but does not include a silicate compound, and which has a pH of 10. a plate-making processing step of subjecting a negative-type photosensitive planographic printing plate precursor, having a radical polymerizable image recording layer on a support, after exposure simultaneously to a development process and a desensitization process using a developer liquid in a single development processing bath of an automatic developing machine that develops the negative-type photosensitive planographic printing plate precursor after exposure, wherein the developer liquid contains from 1% by mass to 10% by mass, based on the total amount of the developer liquid, of a surfactant having a phenyl group or a naphthyl group and at least either an ethylene oxide group or a propylene oxide group, and has a content of an organic solvent having a boiling point in a range of from 100°C to 300°C of 2% by mass or less, based on the total amount of the developer liquid, and substantially does not contain an organic solvent having a boiling point lower than 100°C or higher than 300°C; a waste liquid concentrating step of evaporatively concentrating plate-making process waste liquid produced by the plate-making processing step using a waste liquid concentrating apparatus such that a ratio of a volume of the plate-making process waste liquid after concentration to a volume of the plate-making process waste liquid before concentration is from 1/2 to 1/10; and a reclaimed water producing step of producing reclaimed water by condensing water vapor separated in the waste liquid concentrating step, wherein a pH of the developer liquid is from 6 to 10, wherein a developer liquid is excluded which includes a surfactant and a hydroxide of an alkali metal but does not include a silicate compound, and which has a pH of 10.