In this research, we investigated the influence of the heating of drinking water in the connection pipe under the influence of nearby district heating and the effect this has on water temperatures throughout the domestic drinking water system (DDWS) of a typical Dutch domestic property. We found that stagnant water in the connection pipe warms up fast, reaching the surrounding ground temperature in about 15 min, and these temperatures can be found throughout the house at taps such as the shower and the kitchen tap. Flowing water in the connection pipe is also, depending on the pipe length, heated up several degrees. The prevention of high temperatures in the soil around the connection pipe is the best measure to prevent high drinking water temperatures at the taps.