Received some mini plants (approx. 4cm tall) that I planted in compost to
grow on.

A relative says I should use a spray with tap water as water from a water
butt could have impurities etc.

I have the water from the garage roof filtered through netting and I assume
that from what she says this water would not be suitable..

Can I have your own advice on which is the best "overall" water to use ?
Thanks.

M