Water quality monitoring that accounts for seasonal variability is crucial to ensure safe water services at all times, including groundwater self-supply, which provides drinking water for more than 40 million people in urban Indonesia. Seasonal variation of self-supply water quality remains a key evidence gap in Indonesia and elsewhere; therefore, this study investigated the associations between seasonality and faecal contamination of groundwater self-supply in the Indonesian cities of Bekasi and Metro. The study demonstrated mixed results in terms of associations between seasonality and microbial water quality. McNemar's test showed that high concentrations of Escherichia coli (E. coli) (≥100 MPN per 100 mL) were significantly more likely during the wet season than during the dry season in Bekasi (p = 0.050), but not in Metro (p = 0.694). There was no statistically significant association between the season and the presence of E. coli in self-supply sources for both study sites, nor was there a significant association between the season and the presence of high concentrations of E. coli at the point-of-use. At both study sites, presence and high concentrations of E. coli during the dry season significantly increased the risk of contamination in the wet season, but the predictive power was weak. Regular water quality testing complemented by sanitary inspection is required to understand the contamination risks of self-supply sources.

考虑到季节性变化的水质监测对于确保始终提供安全的供水服务至关重要，其中包括地下水自给，为印度尼西亚城市超过 4000 万人提供饮用水。自给水质的季节性变化仍然是印度尼西亚和其他地区的一个关键证据差距；因此，本研究调查了印度尼西亚勿加泗市和地铁市地下水自给水的季节性与粪便污染之间的关联。该研究表明季节性与微生物水质之间的关联性结果好坏参半。McNemar 的测试表明，在勿加泗，雨季出现高浓度大肠杆菌( E. coli )（≥100 MPN/100 mL）的可能性明显高于旱季 ( p = 0.050)，但在 Metro 则不然 ( p = 0.694）。对于两个研究地点，季节与自供源中大肠杆菌的存在之间不存在统计学上的显着关联，季节与在点处存在高浓度大肠杆菌之间也不存在显着关联。 -使用。在这两个研究地点，旱季大肠杆菌的存在和高浓度显着增加了雨季污染的风险，但预测能力较弱。需要定期进行水质检测并辅以卫生检查，了解自给水源的污染风险。