2.3.1. Diversity

This study addresses diversity through legal pluralism in managing the water supply system for domestic use. According to Tamanaha [17], a "simple" definition of legal pluralism considers the role of social actors when identifying more than one source of "law" (institutions) or normative order within a social arena. Sources of normative ordering include official legal systems (formal institutions); customary, cultural, religious, economic, functional, and community normative systems (general informal institutions according to North [25]); or even multiple legal systems, both formal and informal. According to the IGF, the result is the existence of multiple legal systems (institutions) that determine the governing system and influence the governance object [15].

To address legal pluralism and formal and informal stakeholders, we implemented a multi-level approach, which first evaluated the official legal system at national and state levels for different formal institutions that could potentially overlap or align in the managemen<sup>t</sup> of the water supply system for domestic use. We first reviewed the Ley de Aguas Nacionales (National Water Law; LAN, acronym in Spanish). Likewise, we reviewed other laws and regulations that could influence this system. First, a search was carried out in the Political Constitution of the United Mexican States of 1917 (National Constitution) and the Political Constitution of the Free and Sovereign State of Oaxaca (State Constitution) using Nitro PDF Pro v. 12.4.0.25.9 with the Spanish keywords "agua potable", "agua para consumo humano", and "agua para uso domestico". From this search, we identified articles directly related to the managemen<sup>t</sup> of the water supply system for domestic use. This national and state constitutional review allowed for the identification of other laws at these levels, such as:

National level - • Agrarian Law (regulates land tenure and the collective rights of the 13 selected communities);

**Figure 2.** Macro- and micro-locations of the 13 rural communities in Oaxaca, Mexico, selected for this study. The map shows the political and administrative orders of the municipalities (dotted line), municipal seats (circles), and municipal agencies (rectangles). Municipalities are named after their municipal seats. Source: Prepared by the authors from governmental vector data.

**Table 1.** Operationalization of the properties that comprise the complexity of the governance of the water supply system for domestic use through the diversity, nestedness, and dynamics of the Interactive Governance Framework (IGF). Sources: Prepared by the authors based on Bavinck and Kooiman [15].


Subsequently, we investigated the informal institutions and stakeholders involved in managing the water supply system in the 13 rural communities. A rapid survey was administered to local authorities in 2019 and consisted of four questions classified according to whether the activities corresponded to first-order (operational) or second-order governance (Table S1, Supplementary Materials).

Finally, we cross-referenced the results obtained from formal and informal institutions and stakeholders to define the structure influencing the governance of the water supply system for domestic use in Oaxaca, Mexico.
