Freedom from thirst is a key criterion for dairy cattle welfare but little is known about how competition at the drinker influences the water access of different individuals in a group. Recently, automated methods had been validated to record the individual drinking behaviour of cows and competition at the drinker. However, it is not known if competition at the drinker provides suitable data for identifying the dominance hierarchy in cow groups. We monitored agonistic interactions and drinking behaviour in a group of 22 lactating Holstein dairy cows for 9 consecutive days by video recording and with 6 electronic drinkers. 691 agonistic interactions were identified by video observation during this period, including 299 events at the drinkers. We used the Normalized David’s Score to calculate the dominance score of each cow based on all observed agonistic interactions (Complete DS) and then based on those only at the drinker (Drinker DS). The social ranks of individuals were highly correlated between hierarchies (Pearson’s r=0.82), suggesting that the social hierarchy can be identified using agonistic interactions at drinkers. We further categorized agonistic interactions at drinkers that can potentially be detected based on automated drinker data (i.e. replacements; aggressive contact from the actor cow that resulted in the recipient leaving the drinker and the actor occupying the place within 60s). Replacements (n=235) were used to determine each cow’s social rank (Replacement DS) and found that it was highly correlated with the Drinker DS (Pearson’s r=0.75). Our results indicate that drinkers can be used to identify the dominance position of cows, allowing for the monitoring of the drinking behaviour of cows with a low social rank.