The aim of the article is to study the factors affecting the level of social trust in water quality. Currently, there is strong competition on the market for consumer preferences regarding water consumption: the choice between tap water or bottled water. For a long time, tap water was in an unfavorable market position in relation to bottled water. In recent years, however, we have seen a renewed interest in drinking tap water and an increase in awareness of the negative aspects of bottled water. In this context, the results of many years of sociological research conducted in the Poznań agglomeration in 2004–2021 are interesting, which showed an increase in the percentage of inhabitants of the Poznań agglomeration declaring drinking tap water without boiling it and a decrease in the percentage of those inhabitants who never drink unboiled tap water. The article focuses on two groups of factors influencing these percentages: the quality of water supplied by Aquanet, measured by objective physical, chemical, and biological parameters on the one hand and subjective social level of trust in water on the other. Systematic monitoring of water quality parameters in 2012–2021 proves that rigorous water standards are maintained in terms of chemical, physical and biological parameters. The second group of factors are the promotional campaigns conducted by the Aquanet company, shaping the social image of water and the social changes analyzed in the article, changes in consumption preferences related to the increase in the ecological awareness of the inhabitants. The analysis contained in the article does not exhaust the issue. However, it is sufficient to signal the marketing potential associated with a product without packaging, which is tap water.