This paper describes relations between grout penetration and grouting time to derive stop criteria for grouting. These criteria are the basis for the design and execution of grouting operations. More specifically the relations provide the possibility to judge the dimensionality of the flow channels which are penetrated by the grout based on measured flow and pressure. They also provide rules to decide which stop criterion is suitable in order to achieve the required penetration, based on the rock condition and grout properties. An example, taken from real grouting work is analysed and discussed regarding flow system dimensionality and the applicability of stop criteria.