Civil society has long demanded that human rights monitoring mechanisms be accessible not only for big international NGOs, but also for grassroots and domestic civil society organizations. Ensuring equal participation in these procedures has never been timelier as increasing socioeconomic inequalities widen the barriers for vulnerable populations to engage in transnational advocacy strategies. By using the right to water in the reviews that the UN Committee on Economic, Social and Cultural Rights has conducted to Argentina, Ecuador, and Uruguay as case studies, this article examines how receptive the monitoring mechanism has been to the voices of—and concerns related to—the most vulnerable sectors of society. Through a multi-methods research approach, the study first traces matches in language between alternative reports and the Committee’s lists of issues and concluding observations to identify which voices and claims the CESCR has effectively ‘heard’. It further draws on semi-structured interviews involving civil society actors and former and current members of the Committee. While the findings suggest that efforts for assuring equal weight to all voices are taking place at the CESCR monitoring mechanism, they also unveil how the Committee has overlooked claims when raised by only one alternative report—which have voiced the challenges experienced by groups with intersectional identities. Hence, this article’s contribution rests on the light it sheds on the opportunities and challenges that the Committee confronts to ensure equal participation and make the most vulnerable voices and concerns heard in its monitoring procedure.