Thanks for reaching out! We currently use a symbol to mark water sources, and also hope that hikers would mention something about water sources in their route descriptions. Since we're a crowd-sourced resource, we count on our contributors to send in this vital information. Hopefully as the database grows, there will be more symbols that note water sources as more contributors add information. If you have any details about existing trails, we would really appreciate your help adding that information to the site!
Let me know if you have any questions, or if there's anything else that I can help with.