Rainwater quality is important to many of us, especially when it’s used as a drinking source. We have the potential to get sick from poor quality water, just as we would from poor food hygiene. It ultimately boils down to the storage environment, how it got there and the conditions it’s kept in. If your fridge isn’t cold enough, that chicken dinner might just give you a dose of food poisoning. If you use a thin wall plastic barrel you found, that allows light in to it and the sun heats the water up, then you’re creating an environment that bacteria will thrive in.