Water quality/expiration date

Doreen

For my homecrafting, creams, toners, etc., I use 5 liter jerrycans water that’s been distilled and deionized in accordance with some German quality standards (see picture below).

I also use this water to rinse i.a. measuring cylinders, the probe of the pH meter and prepare buffer fluids for the pH meter. Even with all that I could do (in theory) for several months with only 1 jerrycan. I throw the rest away after 1 or 2 weeks because it doesn’t feel right to use any longer. (At work we throw the water we use for non sterile dermatics away after 1 day, so it feels almost awkward to use it so much longer in private!).
I can get 1 liter bottles from DIY stores, but those are in comparison insanely expensive (around 5 dollars for 1 liter of distilled water).
Another option is use 1 liter bottles of water of a lower water quality (‘demineralized’ water) from the supermarkets/drugstores (you can’t get distilled/deionized water in supermarkets/drugstores here).

• My question is: is it, from a microbial point of view, safe to use the lower quality ‘demineralized’ water? Depending on the formula, I can’t always use sequestering agents.
• And what would be a safe expiration date for these types of water quality?

(The preservatives I use the most are Phenonip P4 (1%), Germall Liquid Plus (0,5%) and Germaben II (1%).  If I use a blend of phenoxyethanol + ethylhexylglycerin (90/10), I follow the hurdle approach (usually I combine it with 0.1-0.2% disodium EDTA, other Aw reducers like caprylyl glycol, glyceryl caprylate).

ngarayeva001

I decided that for my own peace of mind I am just going to boil it. It sounds counterintuitive to boil distilled water but better safe than sorry I guess..

Doreen

@ngarayeva001
What expiration date have you set for your opened bottles of water?
It just feels like a waste to throw around 4 liters away from every bottle, but just like you, I'm also afraid of contamination. I don't boil it though.

ngarayeva001

I usually buy 5lt packs because it's cheaper. Normally I would go through it in 2 months which I believe is too long to expect it to stay clean. Do you think there is a problem with boiling?