I had heard really short times in the couple days range, and then 2 weeks with the bac. water. Reasoning was that in medical setting the stuff is tossed after first recon and use. Recently though, I read somewhere (I can't remember where) a figure of 2 weeks in provided non-bac. water and this was issued by the maker. I suck for not knowing the resource, but I'm near psitive thats what they claimed. The other thing to consider is it may have been brand oriented due to the water provided, but I know it said it was not bac. water and basically addressed the belief that it would only last a few days in the provided water stating that was false. I swear I've heard everything under the sun. I'm gonna use bac. water to be safe.