These races have committed to going cupless. Runners need to bring their own bottles, reusable cups, or other hydration container. Follow the links for more information about these races and why they chose to go cupless.
Are you aware of other cupless races? Email me and tell me!
North Face Endurance Challenge
https://gearjunkie.com/endurance-challenge-ultramarathons-reusable-cups
Race SLO
https://trailrunner.com/trail-news/tuesday-trail-tip-going-cupless-at-trail-races/
RF Events Serious Series
http://trailmarathon.com/
Ragnar Relay Series
https://www.runragnar.com/sustainability
Vacation Races
https://vacationraces.com/2014/08/01/things-to-know-4-cupless-hydration/
Chuckanut 50K
http://chuckanut50krace.com/raceupdates/2013/2/4/going-cupless
Across the Bay 10K
https://acrossthebay10k.com/athletes/cup-less-racing/
Grasslands Trail Run
http://www.grasslandstrailrun.com/faq-items/what-do-you-mean-by-a-cupless-race/
Happy Planet Running 