There are several signs that indicate that your water purifier dispenser needs a new filter. Here are some of the most common ones:

1. Bad odor or taste: If your water has a strange odor or taste, it could be a sign that your filter is no longer working properly

2. Slow filtering speed: If your water dispenser is taking longer than usual to filter water, it could be a sign that your filter is clogged and needs to be replaced

3. Low water pressure: If you notice a decrease in water pressure, it could be a sign that your filter is clogged and needs to be replaced.

4. High number of gallons used: Most filters have a lifespan of a certain number of gallons of water. If you have used up the maximum number of gallons, it’s time to replace the filter.

5. Filter indicator light: Some water purifier dispensers come with a filter indicator light that will turn on when it’s time to replace the filter.