I use a 40 gal. rain barrel to water my small orchid collection (about 30 orchids), as well as the potted plants on my patio.
When I run out of rain water (typcially in the drier season of late summer), I use filtered water from a Britta filter for the orchids. I store the filtered water in gallon jugs so it's ready on watering days. (The patio plants get tap water...they're not quite as spoiled as the 'chids!

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