## 5 Analyzing the Sufficient Water Indicator by Building Type  
The sufficient water indicator suggests a 53% daily water surplus relative to the volume required for domestic, commercial, and service consumption in the study area. This percentage is obtained considering a moderate rainfall event (23.5 mm/24 h), common in the study area according to temporary hydrological data from the local meteorological station ID 13022. The water distribution rationing is real data from the regional operating authority [26], and detailed information about the roof area was obtained from the executive project of the residential area (private communication). This indicator can be tailored to the various rainfall events typical of semi-arid climates. Implementing rainwater harvesting techniques could achieve this surplus, thereby mitigating the current issue of water scarcity. However, due to building structural and functional diversity, this result can only be uniformly extrapolated to some land use types. To formulate appropriate rainwater \begin{table}
\begin{tabular}{l c} \hline \hline
**Indicator** & **Value** \\ \hline Infiltrated water (IW) & 0.23 \\ Available water for consumption (AWC) & 0.17 \\ Runoff water (ROW) & 0.51 \\ Sufficient water (SW) & 1.53 \\ \hline \hline \end{tabular}
\end{table} 
Table 10: Application of the indicators in the study zone. \begin{table}
\begin{tabular}{l c c} \hline \hline
**Land Use** & **Needed Water (\(\mathit{rw}_{i}\)) in (m3)** & **Real Water Supply (\(\mathit{rvs}_{i}\)) in (m3)** \\ \hline Domestic & 8546.8 & 1435.8 \\ Commercial & 172.9 & 36.7 \\ Services & 585.4 & 292.7 \\ \hline Total & 9305.3 & 1765.3 \\ \hline \hline \end{tabular}
\end{table} 
Table 9: Volume of needed water and real water supply per land use. harvesting solutions for each type of building, the sufficient water indicator will be applied specifically to each case. Table 11 illustrates this indicator's behavior by considering the available water supply, regulatory requirements, and the volume of water potentially recoverable through rainwater harvesting. The results indicate that under a scenario of moderate rainfall (23.5 mm) over a 24 h period in the study area, the harvested water would exceed the water requirements for most land use types. Observing the results in Table 11, individualized solutions can be proposed for each building type, optimizing rainwater harvesting. Table 11 indicates a 100% increase in water availability for buildings other than multifamily units. Low-impact development (LID) measures can be implemented individually in these buildings, providing each family with between 1.1 and 2.6 days of the desirable water service. Considering that these families currently use only one-third of the required daily consumption, this water availability extends from 3.33 to 7.8 days, significantly enhancing water access. The situation is more complex for multifamily buildings, as rainwater harvesting does not fully meet one day of each family's desired water requirement. In this case, a communal water tank per multifamily building could be proposed to support common uses such as green space irrigation or cleaning shared areas. Nevertheless, rainwater harvesting in this type of building still doubles water access for each family, considering current consumption. The scenario differs considerably for rooftops of service and commercial areas, where up to nearly 5 and 9 days' worth of water demand can be harvested, respectively. When current supply levels are considered, this can increase to over 20 days for commercial areas. Given this context, a feasible approach would be for each commercial and service building to have its rainwater harvesting technique or to redirect part of the harvested water to shared storage tanks supplying multifamily buildings, thereby partially alleviating water scarcity for this specific population.