Water is fine a lot longer than that, btw. I live off-grid and fill a cistern with Canadian tap water (minimal chlorine). I peek in the cistern once a year or s

Water is fine a lot longer than that, btw. I live off-grid and fill a cistern with Canadian tap water (minimal chlorine). I peek in the cistern once a year or so, fill by truck every few months. I have access to a microbiology lab and have tested the water for both bacterial and fungal concerns periodically.