Chicago Marathon Adopts Water Refill Stations For Runners

The Chicago Marathon will let runners refill their own bottles and flasks at four points on the course on Oct. 11, making it the only one of the seven World Marathon Majors to offer the service to its whole field, and it is doing so without removing a single paper cup from the route.

Race organizers announced the program on Tuesday with Culligan International, the water treatment company that already supplies the finish line, and HydraPak, which makes the flasks and collapsible cups the program is built around. Four filtered water units will sit immediately before aid stations 4, 7, 12 and 16, at miles 5.7, 10.1, 15.7 and 20.3. Runners may fill what the race describes as “their own approved self-carried hydration gear,” a category HydraPak lists as soft flasks, handhelds, reservoirs and reusable race cups. The announcement was first reported by NBC Chicago.

“Sustainability has been one of our core focus areas for more than a decade, and the introduction of on-course refill stations represents an important next step,” said Carey Pinkowski, the executive race director.

All 20 of Chicago’s aid stations will hand out water and Gatorade Endurance in cups as they always have, spaced one to two miles apart. The refill points sit alongside them, for runners carrying their own bottles.

Paris went the other way in April. The Paris Marathon removed cups and bottles from its aid stations altogether and required its field to carry containers, and we argued at the time that the trade was a poor one, putting the cups at roughly 0.027 percent of an event footprint of about 54,300 tons of CO2 equivalent while shifting the burden onto the slowest runners in the field. Paris is not one of the Majors, which is why Chicago can claim a first.

The four stations will serve a field of more than 55,000. Research commissioned by HydraPak and led by crowd scientist Marcel Altenburg modeled refill systems at the 2024 and 2025 La Jolla Half Marathons and concluded that 4.2 dispensing spouts per 100 runners per minute deliver uninterrupted flow with a 150 percent contingency, and that a system of that size could serve up to 250 runners per minute. It also found a single dispenser can remove the need for as many as two volunteers. Chicago has not said how many spouts each of its four stations will carry.

Refill stations themselves are not new to the race. Its sustainability page states that they were introduced in 2024 and were available at eight aid stations in 2025, and that the Culligan stations in Grant Park kept 14,680 plastic bottles out of use in 2024. What is new this year is the formal permission to fill personal gear during the race, at dedicated units placed ahead of four aid stations.

The race’s own gear rules have not been updated to match. Its course and amenities page permits fuel belts and handheld bottles but says hydration backpacks are not allowed, while HydraPak’s approved list for the program includes reservoirs. Runners planning their aid station strategy around a vest should check the participant guide when it is published.

The change follows years of lobbying by Tina Muir, the former Great Britain international who hosts the Running for Real podcast. In an Instagram post on Tuesday, Muir said she had “persistently pestered so many people in the running industry, desperately trying to push this movement forward,” and set out the objections she had spent years answering, from sloshing bottles to refill speed. She has said she ran 2:54 at the London Marathon while carrying a bottle and refilling on course.

HydraPak listed two refill points, at miles 4.1 and 9.7, for the series’ half-marathon in June. The marathon field is the largest in the race’s history, drawing more than 55,000 runners from over 100 countries and all 50 states, with an elite field led by the defending champions. The first wave leaves Grant Park at 7:30 a.m. on Oct. 11.