Water quality assessments are essential for providing information regarding integrated water resource management processes. This study presents the results of a spatial and seasonal surface water quality assessment of the Burío river sub-catchment in Costa Rica. Fourteen sample campaigns were conducted at eight sample sites between 2005 and 2010. Seasonal variations were evaluated using linear mixed-effects models where dissolved oxygen, total solids, and nitrate showed significant differences between dry and wet seasons (p < 0.05). Cluster analysis identified three clusters at the top, middle, and bottom of the catchment that were consistent with land use patterns, and principal component analysis identified the main parameters that were affecting 84% of the total variance in water quality (biochemical oxygen demand, dissolved oxygen, total phosphate, and nitrate). The National Sanitation Foundation Water Quality Index (NSF-WQI) results indicated the majority of the river consisted of mainly “medium” water quality, although “bad” and “good” water quality results were identified depending on sample site and season. This methodological approach provides a useful monitoring technique for local governments that can be used for further remediation strategies.

Water quality information is essential supporting decision making in water management processes. The lack of information restricts, at some point, the implementation of adequate sanitation, which is still scarce in developing countries. In this study, an ecosystemic water quality assessment was conducted in the Virilla river in Costa Rica, in a section of particular interest for future sanitation development. It included the monitoring of physical, chemical, microbiological and benthic macroinvertebrate parameters from 2014 to 2016. Mutivariate statistics and water quality indexes were used for data interpretation. Results indicated that water quality decreased downstream towards more urbanised areas. Particularly, extreme values of phosphorous, nitrogen and E. coli were found. Sample sites were grouped in two clusters, which were consistent with land use. Benthic macroinverterbrates diversity was predominantly represented by Baetidae, Chironomidae, Leptohyphidae, Hydropsychidae, Simuliidae and Physidae. They were mostly influenced by water temperature, nitrite, ammonium, soluble reactive phosphorous, total solids, alkalinity, nitrate and total suspended solids. Three water quality indexes consistently showed the poor condition of the water body. The overall results indicate that the main sources of pollution in the river are likely to be wastewater discharges. Thus, special efforts should be undertaken regarding its regulation in the country.

Vegas-Las Palmas is a rural settlement located in the southern Caribbean region of Costa Rica on the border with Panama. Its population does not have access to potable water, and inhabitants depend on water from wells at the water table level to meet their needs. These wells lack basic infrastructure to protect this water from contamination. In this study, water quality was evaluated at 12 wells from 2014 to 2016 (n = 72). The results revealed high concentrations of faecal coliforms and Escherichia coli with maximum values of 4.6 × 10⁴ MPN/100 mL and 1.1 × 10⁴ MPN/100 mL, respectively. In addition, maximum values of pH, conductivity, turbidity, Ca, Mg, K, Fe, Mn, Cd and Pb were found to be outside the standard limits (nationally and internationally) for potable water. Possible sources of water contamination are associated with the geomorphological characteristics of the area, as well as with hydrometeorological and anthropogenic factors such as the lack of sewerage, the presence of latrines, animals near the wells and the use of agrochemicals. The water quality was heterogeneous among wells, and all of them were found to have conditions that caused water to be unfit for human consumption.

Community-based water management organisations (CBWMOs) play an important role in providing water services worldwide. However, there is some debate as to their capacity to sustain a safe drinking water supply considering the current socioeconomic and climate scenarios. Here, we present an integrated water quality assessment of the supply system of a CBWMO in Concepción of San Ramon, Costa Rica. Major ions, trace metals, and coliforms were analysed in the households and water sources over a 1-year period. The spring risk assessments and the water quality of the main river in the catchment were also carried out. We found that although the supplied water meets adequate standards, spatial and temporal changes in the water quality of the sources exist. Springwater composition is mainly driven by rock–water interaction processes, but early signs of potential anthropogenic pollution were found. The springs showed concentrations of NO3- above natural levels and microbial contamination in 37 and 18% of the cases, respectively. River water quality showed a distinct composition, which is consistent with the anthropogenic pressures in the catchment. This study provides useful information on how water quality assessments can be used beyond regulatory processes to improve planning by CBWMOs to ensure water security.