For those interested in making their own. Based on my research you need to obtain WFI quality water. WFI stands for Water for Injection.
www.irvinesci.com
You could then add benzyl alcohol as a preservative to allow storage and use. Adding precisely enough benzyl to get to 0.9 percent. I'd recommend sterile vials to mix this in and keeping your workspace clean.
Don't use tap, distilled or other types of water. You might not get sick from it, but it ain't right. If you mix your benzyl and WFI water together, it still isn't as good as USP-grade Hospira branded water. But head and shoulders better than most other recipes I see posted.

Water for Injection (WFI) Quality Water
Water for Injection (WFI) Quality Water* Water for Injection (WFI)* Quality Water is the most suitable water available for producing cell culture media, reconstitution of biochemical reagents, and as a final rinse water for critical applications. WFI Qual

You could then add benzyl alcohol as a preservative to allow storage and use. Adding precisely enough benzyl to get to 0.9 percent. I'd recommend sterile vials to mix this in and keeping your workspace clean.
Don't use tap, distilled or other types of water. You might not get sick from it, but it ain't right. If you mix your benzyl and WFI water together, it still isn't as good as USP-grade Hospira branded water. But head and shoulders better than most other recipes I see posted.