In Germany, the odorization of gases for public gas supply is regulated by the DVGW work sheet G 280-1 titled "gas odorization". Here the possibility of using different odorants like THT, mercaptans and the sulfur-free odorant Gasodor S-Free with their specific minimum-odorant-concentration is stated. The minimum-odorant-concentration ensures the warning smell of the gas. Gas odorization is the responsibility of the local gas suppliers. The gas suppliers must ensure that there is compliance with the minimum-odorant-concentration (warning smell) in their distribution network. In the context of a DVGW R & D project, an odor reporting statistic for all odorants used in Germany was created for the time period 2008 to 2014. The survey included aspects like the total number of customer odor reports, the percentage of confirmed reports (detection of a leak) and the results of odorant measurements for detecting the minimum-odorant-concentration. The analysis of this odor reporting statistics showed that all odorants ensure a high level of security in the public gas supply. Another DVGW R & D project focused on the odorization of biogas. Some gas suppliers reported changes in odor intensity and odor character of the warning smell. The project included a comprehensive measurement program at biogas facilities, olfactory tests and theoretical consideration of possible reactions of the odorant with components of conditioned biogas. Some components of LPG (for used for adaption of the heating value of biogas) could be identified as the main cause of the odor changes. Following the project results, recommendations for the gas suppliers have been developed. In the talk, the results of these two R&D projects will be presented.