Distilled water forever! It will not harm you! Rainwater is naturally distilled, and the "acidity" of distilled water is extremely weak, though low on the scale. The reason distilled water will cure a bladder infection is that it is the most cleansing water in existence, with full ionic capacity for flushing toxins, metabolic by-products, and pathogens.
Uti or interstitial cystitis and acid/alkaline
Please read this if you have a UTI or IC!!
I have been researching and this is my conclusion: Your urine is either too acid OR too alkaline. It may have caused bacteria to grow, or if cultures couldn't detect bacteria, it could just be irritated as in IC. I always read that my urine was too acidic. When I tried to make it more alkaline I was even more miserable! Once, when I was taking a barley powder product for it's health benefits, my bladder got worse. It was too alkalinizing. I read that DISTILLED WATER was very acidic, so I chugged a gallon that day. What a relief! (One wouldn't want to drink distilled water for more than three days, as prolonged use can be detrimental, but it is easy on the struggling kidney and bladder.)
Make sure you know if your urine is too acidic or too alkaline before you treat yourself. You can buy testing strips at a pharmacy. The doctors in our rural area would think I was weird if I started talking about natural cures and acid/alkaline. Be your own doctor if possible. Best wishes.