This is 1 Gallon in freedom units.
That being said, for a cat or small dog, I will vouch for this as an awesome alternative to constantly refilling a smaller water dish. We have a 3-gallon model for our four dogs, two of which are small (15-20 pounds) and the others medium (30-40 pounds), and we have to clean and refill about once a week.
One more note though, I will say that since we got the larger model with a charcoal filter insert, it gets less grimy than this one that doesn’t have one. Bacterial growth is normal of course, especially in standing room temperature water, so just make sure you give it a good hot soapy water rinse often!!
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