A method for estimating a location of a leak (x) in a pipe (1). A liquid of a known density is fed into the pipe at a first inlet pressure (P1). When the liquid achieves a substantially steady flow rate, the flow rate passing into the pipeline is recorded. This step is repeated at a second, different, inlet pressure (P2). Using this data, an estimate of the leak location (x) and the area of the leak is calculated by simultaneously solving an expression which is based on relating the frictional energy losses of the liquid travelling through the pipeline (1) to the pressure in the pipeline at the leak (Pleak) and the flow rate of liquid from the leak.