I took a sample of rainwater collected in a rain barrel in my backyard. I thought it would be interesting to see if anything can grow in this water that just sits in this barrel because rain as well as gutter water from the garage roof empties into it. When I first turned on the tap the water has a slight yellow tint so I would expect to see higher fungal growth than normal tap water or if I were to sample rainwater that has not been sitting there for such a long time.
