Yes, holy water can go bad in that it can grow algae, mildew, etc. I’ve seen some nasty green floaty things in holy water, I once saw a holy water font with a transparent aquatic creature swimming around in it.
I’d suggest when you bring home holy water, first make sure your container is clean and rinsed with bleach before you use fill it. Only take as much as you will use in a few weeks, or store it with the lid off so it naturally evaporates.
Old holy water can grow a little algae. I personally don’t find that a barrier to use unless it smells, given that I don’t drink the holy water. It doesn’t become un-holy because God is letting little green plants and probably invisible bacteria grow in it.
When you use up the holy water, I suggest cleaning the bottle out very well with a brush and detergent before you put in new water, or maybe toss out the bottle and use a fresh one. And keep it away from sunlight, like in a closed cupboard or windowless room. Sunlight makes the green stuff grow in it.
Last Sunday I went to Mass in a parish I’m not familiar with. While I’m used to pristine holy water fonts in my usual churches, this one had huge slimey grey things floating in them. Eeek.
A pastor colleague in one of my former (Reformed) parishes once met with parents to prepare their baby’s baptism, and was proudly shown a bottle of Jordan water the grandparents had brought back from Holy Land to be used at their first grandchild baptism, many years before he was born. He had to tell them it might be best to filter it, boil it, and drop a water purifying pill in it for good measure, unless they really wanted the baby to have a green forehead on his baptism pictures, and to have himself distribute communion with algae and other organisms on his hands afterwards.
Oh my. At my parish I don’t remember I’ve ever seen people even
look at the fonts. if they use them they put their fingers in,
that in it’s self is unsanitary as kissing things. I do not guess
it’s required to use holy water fonts. Mine has indeed sat for a
while. From before I knew there was holy water in the parish for
Mine has sat from before I knew you could get new water from the
parish. IDK how long this water has sat; water in parish. In an hour chlorine can
evaporate off, thankfully. But in this case IDK if it’s changed much by persons in the parish or
I’m not sure it has to be one’s own parish pastor to do the blessing. Can’t it be any ordained priest in good standing?
When we were having our log home built, I had my parish priest come out and bless it, which he gladly did. Even so, our roofer fell off the roof shortly thereafter, though he wasn’t seriously injured. Made me pause a bit.