Display shows ADD WATER or a water droplet icon and brewing will not start.

Safety first: Unplug the coffee maker before removing the reservoir.

Check water level and seating:

• Fill the reservoir to at least the minimum fill line.
• Reinstall the reservoir firmly, ensuring it clicks or seats fully into place.
• Gently tap the side of the reservoir to free any stuck air bubbles.

Inspect float (if visible):

• Look for a small plastic float inside the reservoir. Ensure it moves freely up and down.
• If it is stuck, remove the reservoir and rinse with warm soapy water, then flush thoroughly.

Internal sensor check (advanced):

• Some Oster models use a magnetic reed switch or optical sensor under the reservoir. Remove the bottom or side panel to access it.
• Ensure the sensor is clean and its wiring is intact.

If the ADD WATER message persists with a full, properly seated reservoir, the water level sensor or its magnet/float may need replacement.