As compared to AC microgrids, DC microgrids reduce the hardware complexity of converter-dominated power distribution in the presence of a high number of renewable energy sources, energy storage systems and energy efficient loads. Another frequently highlighted advantage is their resiliency and tolerance against AC grid disturbances resulting in improved overall power quality. However, with respect to power quality, the question arises whether existing international power quality standards and metrics remain applicable in DC microgrids or require adjustments. Therefore, this paper critically revises the definitions and power quality indicators specified in IEC 61000 and IEEE Std1159. The resulting review is essential to unambiguously define the responsibilities of the microgrid operators, customers and device manufacturers. Apart from that, causes and consequences of power quality issues in DC microgrids are discussed.