Water-carrying household appliance, in particular dishwasher, with a sensor apparatus for determining at least one property of a liquid, which is the mains water supplied to the water-carrying household appliance, wherein the sensor apparatus comprises: a first laser and a second laser, wherein the first laser is designed to emit a first light beam, which has a first predetermined beam characteristic with a first determined light intensity, the second laser is designed to emit a second light beam which has a second predetermined beam characteristic with a second determined light intensity, at least one container arranged in front of the first and the second laser (L1, L2), which is filled with a mixture of the liquid and at least one indicator, at least one detector for detecting a light intensity, transmitted through the container filled with the mixture, of the first light beam emitted by the first laser and for detecting a second light intensity, transmitted through the container filled with the mixture, of the second light beam emitted by the second laser, and at least one further container for receiving the at least one indicator and at least one controllable supply apparatus arranged between the at least one container and the at least one further container for supplying the at least one indicator from the at least one further container into the at least one container, wherein the at least one indicator comprises a first indicator and a second indicator, and wherein the sensor apparatus comprises a water hardness sensor for determining a hardness of the liquid, wherein the first indicator is suited to forming a soluble product by means of a chemical reaction with calcium ions and/or magnesium ions contained in the liquid, which, in the case of an emission wavelength of the first laser, has an absorption as a function of the concentration of the calcium ions and/or magnesium ions contained in the liquid, but has no absorption in the case of an emission wavelength of the second laser, and the sensor apparatus additionally comprises a pH sensor for determining a pH value of the liquid, wherein the second indicator is suited to forming a soluble product by means of a chemical reaction as a function of the pH value of the liquid, which in the case of an emission wavelength of the second laser has an absorption but in the case of an emission wavelength of the first laser has no absorption, and wherein the sensor apparatus has a determination unit, which is designed to determine the hardness and the pH value of the liquid as a function of the detected light intensities. a first laser and a second laser, wherein the first laser is designed to emit a first light beam, which has a first predetermined beam characteristic with a first determined light intensity, the second laser is designed to emit a second light beam which has a second predetermined beam characteristic with a second determined light intensity, at least one container arranged in front of the first and the second laser (L1, L2), which is filled with a mixture of the liquid and at least one indicator, at least one detector for detecting a light intensity, transmitted through the container filled with the mixture, of the first light beam emitted by the first laser and for detecting a second light intensity, transmitted through the container filled with the mixture, of the second light beam emitted by the second laser, and at least one further container for receiving the at least one indicator and at least one controllable supply apparatus arranged between the at least one container and the at least one further container for supplying the at least one indicator from the at least one further container into the at least one container, wherein the at least one indicator comprises a first indicator and a second indicator, and wherein the sensor apparatus comprises a water hardness sensor for determining a hardness of the liquid, wherein the first indicator is suited to forming a soluble product by means of a chemical reaction with calcium ions and/or magnesium ions contained in the liquid, which, in the case of an emission wavelength of the first laser, has an absorption as a function of the concentration of the calcium ions and/or magnesium ions contained in the liquid, but has no absorption in the case of an emission wavelength of the second laser, and the sensor apparatus additionally comprises a pH sensor for determining a pH value of the liquid, wherein the second indicator is suited to forming a soluble product by means of a chemical reaction as a function of the pH value of the liquid, which in the case of an emission wavelength of the second laser has an absorption but in the case of an emission wavelength of the first laser has no absorption, and wherein the sensor apparatus has a determination unit, which is designed to determine the hardness and the pH value of the liquid as a function of the detected light intensities.