We developed length-mass regressions for 16 aquatic gastropods collected from 27 springs in Nevada, United States. The relationship between shell length and body mass for all species was best described by fitting a power function. The mean value of the exponent b (2.40 ± 0.39) was lower than reported for other aquatic gastropods, particularly for smaller genera, such as Pyrgulopsis and Tryonia. Length-mass regressions of gastropods showed intraspecific variation, as well as spatiotemporal variation among the same species. Certain habitat characteristics, especially water temperature, may play a key role in determining growth rates and ultimately length-mass regressions in this study. Although the power term b showed high variability when the same species (Melanoides tuberculata, Pyrgulopsis lockensis, and Pyrgulopsis turbatrix) were collected from different springs, the power term was similar when the same species (Pyrgulopsis marcida) was collected from the same spring during different seasons and years. Therefore, we suggest that published equations should be used with caution and only when habitat characteristics and length ranges are similar compared to those in the literature.