Every CO2 supplier we could find in the Milwaukee area (Wisconsin) was checked one by one, and 15 of them made the list. 10 will refill the cylinder you walk in with. 1 only swap it for a different tank, which matters if yours is new or an odd size. 4 would not confirm either way, so those are marked call to confirm rather than guessed at. 3 confirm food grade CO2 for anything you actually drink; the common sizes here are 10lb, 5lb, 15lb; most cover soda, homebrew, welding.
15places listed
10confirmed refill
3confirmed food grade
Last checked September 2026
Sorted for you: places that refill your own tank come first, then the most complete, confirmed listings. Exchange-only and unconfirmed spots follow.
KeyRefillBothExchangeConfirm
Badger Carbonic Distributing
Refill
20155 Colony Ct · Brookfield, WI 53045
ServiceRefill
Food gradeYes
Tank sizes5lb / 10lb / 15lb / 20lb / 50lb
Your cylinderYes, refills yours
homebrewsoda
Hours 24-hour service
Official current CO2 service page explicitly states that Badger Carbonic refills CO2 cylinders and lists 5 lb, 10 lb, 15 lb, 20 lb, and 50 lb cylinders. Official materials also identify food-grade CO2 and Milwaukee metro service. The Brookfield physical location is supported by a current reputable business directory because the official site does not publish a street address.
Hours Mon-Thu 07:30-17:00; Fri 07:30-16:00; Sat 08:00-12:00; Sun Closed
Current local and manufacturer-distributor evidence verifies the active West Allis branch, address, phone, hours, and public email. Current service evidence states it sells and exchanges cylinders including food-grade CO2, operates an onsite gas fill plant, and provides consumer CO2 refill service. Recent September 2025 Milwaukee community evidence reports both exchanges and refills. Exact supported refill or exchange sizes were not published.
Current map listing verifies the active Milwaukee cylinder-service business, address, phone, and hours. Milwaukee community evidence reports while-you-wait full-pressure CO2 refills and specifically documents a 5 lb refill. That service evidence is from 2024, so food-grade status and any other cylinder sizes remain unknown.
Hours Mon 09:00-15:00; Tue-Fri 09:00-21:00; Sat 09:00-20:00; Sun 10:00-17:00
Official current location page verifies the Brown Deer store, address, phone, hours, and email. Recent September 2025 Milwaukee community evidence reports a quick 10 lb CO2 tank fill at this specific Brown Deer location. Older community evidence also identifies Brown Deer as the Otto's location with CO2 service. Food-grade status and other cylinder sizes were not verified.
Hours Wed 12:00-20:00; Fri 12:00-20:00; Sat 10:00-18:00; Sun 10:00-18:00; Mon-Tue-Thu Closed or by reservation
Official current site verifies the active Big Bend paintball facility, address, phone, email, and hours. Its current paintball pricing states CO2 tank fills up to 24 oz, and the site says employees fill CO2 tanks. Food-grade status is not applicable and remains unknown.
Hours Mon-Fri 09:00-17:30; Sat 09:00-13:00; Sun Closed
Official current services page explicitly lists CO2 refill and testing. The same official page verifies the West Allis address, phone, public email, and hours. Exact supported cylinder sizes and explicit food-grade designation were not published.
Official current FAQ explicitly states that Discount Liquor fills CO2 tanks when the cylinder is within certification, and specifically says SodaStream fills are available only at the Milwaukee store. Official contact information verifies the branch address, phone, hours, and email. Exact tank sizes and food-grade designation were not published.
Official current company FAQ states that Discount Liquor fills CO2 tanks and separately notes that SodaStream filling is only at Milwaukee, supporting standard CO2 refill service at the listed Waukesha store but not SodaStream service there. Official contact information verifies this physical branch, phone, hours, and email. Tank sizes and food-grade status remain unknown.
Hours Mon Closed; Tue-Sat 09:00-18:55; Sun 09:00-16:55
Current store page explicitly advertises a CO2 tank refill station and states that it refills CO2 tanks for beer kegerator systems. Current site information verifies the physical Oconomowoc store, phone, and hours. A clickable email control is present but no reliable public email address was exposed, so email remains unknown.
Official current site verifies the Milwaukee address and phone and explicitly lists CO2 gas refills, bulk CO2 gas, and beverage gas cylinders serving the Greater Milwaukee Area. Older directory references to 1345 N 74th St are treated as stale because the current official contact page lists 5707 W Vliet St. No reliable public email, food-grade designation, or supported cylinder sizes were verified.
Hours Mon-Fri 07:30-20:00; Sat 07:30-18:00; Sun 08:00-17:00
Current official Ace store information identifies SodaStream exchanges at this exact Oconomowoc branch. This is a 60 L SodaStream carbonator exchange only and is not represented as standard 5 lb or 20 lb CO2 cylinder service. Current local business information verifies address, phone, and hours. No public branch email was verified.
Official current MacCarb materials verify the New Berlin depot, corporate phone, public orders email, and beverage plus industrial gas service. Current product information describes beverage-grade carbon dioxide in its beverage gas products. Public evidence does not establish walk-in portable same-cylinder refill versus exchange behavior or supported cylinder sizes at this depot.
Official current site verifies the Milwaukee physical location, phone, public email, hours, and cylinder gas service. Its current gas catalog explicitly includes industrial carbon dioxide. Public branch evidence does not clearly distinguish portable same-cylinder refill from exchange, food-grade status, or supported cylinder sizes.
Hours Mon-Fri approximately 07:00-15:30; Sat-Sun Closed
Official current branch page verifies the physical Milwaukee store and explicitly lists carbon dioxide among gases available, along with a branch-specific email. Current branch hours may show holiday-specific exceptions, so the recurring weekday schedule is summarized conservatively. Portable refill versus exchange behavior, food-grade status, and sizes were not published.
Official current branch page verifies this Milwaukee retail gas location. Current MATHESON beverage-industry materials list carbon dioxide, while a current local homebrew suppliers directory lists the same physical location for brewing gas supply. The email is a current corporate general contact rather than branch-specific. Portable refill versus exchange behavior, food-grade status, and sizes remain unknown.