Even if you live in an apartment building like me, you can still grow organic herbs in pots for your infused waters. The secret to growing herbs in containers is sunlight. This means you should position your plants on the side of your apartment or house that gets the most sun, even if this means having your plants indoors.
Some suggested herbs for infused waters: basil, mint, lemon sage, rosemary, marjoram, and lemon verbena. Here’s also an urban garden article to give more detail.
A neighbor down the street has an overgrowth of mint, so I also help myself to a stalk every now and then. If you walk around city neighborhoods and keep your eyes open, you’ll likely see rosemary, lavender, and mint. They are often used as landscaping plants or run wild as weeds. Tip: be sure to thoroughly wash any plucked stems to clean off any city grime!