Faecal indicator organisms (FIOs) are limited in their ability to protect public health from the microbial contamination of drinking water because of their transience and time required to deliver a result. We evaluated alternative rapid, and potentially more resilient, approaches against a benchmark FIO of thermotolerant coliforms (TTCs) to characterise faecal contamination over 14 months at 40 groundwater sources in a Ugandan town. Rapid approaches included: in-situ tryptophan-like fluorescence (TLF), humic-like fluorescence (HLF), turbidity; sanitary inspections; and total bacterial cells by flow cytometry. TTCs varied widely in six sampling visits: a third of sources tested both positive and negative, 50% of sources had a range of at least 720 cfu/100 mL, and a two-day heavy rainfall event increased median TTCs five-fold. Using source medians, TLF was the best predictor in logistic regression models of TTCs ≥10 cfu/100 mL (AUC 0.88) and best correlated to TTC enumeration (ρ_s 0.81), with HLF performing similarly. Relationships between TLF or HLF and TTCs were stronger in the wet season than the dry season, when TLF and HLF were instead more associated with total bacterial cells. Source rank-order between sampling rounds was considerably more consistent, according to cross-correlations, using TLF or HLF (min ρ_s 0.81) than TTCs (min ρ_s 0.34). Furthermore, dry season TLF and HLF cross-correlated more strongly (ρ_s 0.68) than dry season TTCs (ρ_s 0.50) with wet season TTCs, when TTCs were elevated. In-situ TLF or HLF are more rapid and resilient indicators of faecal contamination risk than TTCs.

粪便指示生物 (FIO) 保护公众健康免受饮用水微生物污染的能力有限，因为它们的短暂性和提供结果所需的时间。我们根据耐热大肠菌群 (TTC) 的基准 FIO 评估了替代的快速且可能更具弹性的方法，以表征乌干达城镇 40 个地下水源在 14 个月内的粪便污染特征。快速方法包括：原位色氨酸样荧光 (TLF)、腐殖质样荧光 (HLF)、浊度；卫生检查；和总细菌细胞通过流式细胞术。在六次抽样访问中，TTC 变化很大：三分之一的来源检测为阳性和阴性，50% 的来源的范围至少为 720 cfu/100 mL，两天的强降雨事件使 TTC 中位数增加了五倍。使用源中位数，_s 0.81)，HLF 表现相似。TLF 或 HLF 与 TTC 之间的关系在雨季比旱季更强，而 TLF 和 HLF 与总细菌细胞的相关性更高。根据互相关，使用 TLF 或 HLF（最小 ρ _s 0.81）比使用 TTC（最小 ρ _s 0.34）时，采样轮次之间的源排名顺序更加一致。此外，当 TTC 升高时，旱季 TLF 和 HLF与雨季 TTC 的互相关（ρ _s 0.68）比旱季 TTC（ρ _s 0.50）更强。原位 TLF 或 HLF 是比 TTC 更快速、更具弹性的粪便污染风险指标。