Yes, you are absolutely allowed to bring your own water bottle into EPCOT and all other Walt Disney World theme parks. Disney has a very guest-friendly policy regarding outside food and non-alcoholic beverages, provided they are for personal consumption and are not stored in glass containers. You can bring either a factory-sealed plastic bottle or a reusable bottle made of plastic or metal. Bringing a reusable bottle is highly recommended, as EPCOT features numerous bottle-filling stations and water fountains throughout the park, particularly in newer areas like World Celebration and the Odyssey building. Additionally, you can request a complimentary cup of ice water at any quick-service dining location. Just be sure your cooler or bag meets Disney’s size requirements (no larger than 24" long x 15" wide x 18" high) and that you do not bring in loose ice; reusable ice packs are the preferred way to keep your drinks cold while navigating the park.