**5. Methods and Reviews Related to Water Quality and Health**

Systematic review (SR) and meta-analysis (MA) are methods which have been used extensively to elucidate the relationships between microbiological contamination and ill health. As climate change will impact water contamination, an examination of systematic reviews relating to water quality has been undertaken. A SR of the effectiveness of interventions to reduce the health impact of climate change around the world, found a weak evidence base and gaps in dealing with extreme weather events [78]. This follows a previous SR [79]. The seasonal differences in faecal contamination of source waters used for supplying drinking water have been examined in a SR [80]. They found increased contamination in the wet season. A general review of wider evidence for pathogens being waterborne and the impacts of climate are included in the review of pathogens (Table A1, Appendix A).
