Drinking lemon water daily can have downsides, mainly because lemon juice is acidic. The main concerns are tooth enamel wear and possible worsening of heartburn or acid reflux in people who are sensitive to citrus.
Frequent exposure to acidic drinks can soften enamel over time, especially when lemon water is sipped throughout the day. This may increase the risk of tooth sensitivity, enamel erosion, and visible tooth wear. The source material notes that this risk is based mostly on research about acidic drinks and citrus products, not lemon water specifically.
Lemon water may also trigger or worsen reflux symptoms in some people. Citrus fruits and juices are commonly reported as heartburn triggers, although the evidence is not fully consistent. People with GERD, frequent heartburn, existing enamel erosion, dry mouth, or sensitive teeth may need to be more cautious.
To reduce risk, avoid sipping lemon water all day, and rinse the mouth with plain water afterward. Anyone with frequent heartburn, tooth sensitivity, or enamel wear should speak with a dentist or healthcare professional for personalized advice.