It depends on the type of filter you have. Some filters can last for up to 10,000 gallons, while others may only last for 1,000 gallons. It's important to regularly check your filter's expiration date and replace it when necessary to ensure you're getting the best performance possible. If you're not sure how long your gravity water filter will last, consult the manufacturer's instructions or contact customer service. They should be able to tell you exactly how long your specific filter is expected to last.