A method for determining a leak rate (Lx) of a water pipe section in which drinking water is conveyed, comprising the following method steps: a) manually opening a closable shut-off valve on the otherwise substantially shut-off water pipe section by an operator until the pressure of the drinking water in the water pipe section has exceeded an upper pressure limit (Po) because of drinking water flowing in; b) manually closing the shut-off valve by the operator , measured values of a first pressure curve being subsequently measured over time and stored, until the pressure of the drinking water in the water pipe section has dropped below a lower pressure limit (Pu) because of the drinking water flowing out at the leak , characterised by the steps of c) manually opening the closable shut-off valve of the otherwise substantially shut-off water pipe section by the operator until the pressure of the drinking water in the water pipe section has exceeded the upper pressure limit (Po) because of drinking water flowing in, d) manually closing the shut-off valve by the operator and opening an outlet valve having a known leak rate (Lv), measured values of a second pressure curve being subsequently measured over time and stored, until the pressure of the drinking water in the water pipe section has dropped below the lower pressure limit (Pu) because of the drinking water flowing out at the leak and the drinking water flowing out through the outlet valve , e) comparing measured values of the first pressure curve with measured values of the second pressure curve , the unknown leak rate (Lx) of the leak being derived in relation to the known leak rate (Lv) of the outlet valve from the comparison of the measured values. a) manually opening a closable shut-off valve on the otherwise substantially shut-off water pipe section by an operator until the pressure of the drinking water in the water pipe section has exceeded an upper pressure limit (Po) because of drinking water flowing in; b) manually closing the shut-off valve by the operator , measured values of a first pressure curve being subsequently measured over time and stored, until the pressure of the drinking water in the water pipe section has dropped below a lower pressure limit (Pu) because of the drinking water flowing out at the leak , characterised by the steps of c) manually opening the closable shut-off valve of the otherwise substantially shut-off water pipe section by the operator until the pressure of the drinking water in the water pipe section has exceeded the upper pressure limit (Po) because of drinking water flowing in, d) manually closing the shut-off valve by the operator and opening an outlet valve having a known leak rate (Lv), measured values of a second pressure curve being subsequently measured over time and stored, until the pressure of the drinking water in the water pipe section has dropped below the lower pressure limit (Pu) because of the drinking water flowing out at the leak and the drinking water flowing out through the outlet valve , e) comparing measured values of the first pressure curve with measured values of the second pressure curve , the unknown leak rate (Lx) of the leak being derived in relation to the known leak rate (Lv) of the outlet valve from the comparison of the measured values. <EOS>