Short answer: no, it is not really normal for a neighbor’s urban planter box to keep leaking onto your balcony. A small amount of overflow after heavy rain or watering can happen, but a persistent drip or steady stream usually points to a drainage or maintenance problem. Water should be captured by the planter’s tray or drainage system, not allowed to run onto someone else’s space.
Common causes include missing or undersized saucers, clogged drainage holes, overwatering, a cracked planter, poor placement, or a planter that sits directly on the balcony slab without risers. In some cases, the leak may not come from the planter at all; it could be water travelling along the balcony edge, through a shared wall, or from failing waterproofing. That is why it helps to identify the source before making assumptions.
Start by documenting the leak with photos or short videos, noting when it happens and where the water lands. Then speak to your neighbor calmly and specifically. You might say, “I’ve noticed water dripping onto my balcony from your planter box. Could we check whether the drainage tray is working?” A polite, practical approach is usually more effective than an accusatory one. Suggest simple fixes such as adding a waterproof saucer, raising the planter on pot feet, clearing drainage holes, reducing watering, or placing a waterproof mat underneath.
If the leak continues, ask your building management or HOA to review the situation, especially if there is any risk of structural damage, mold, or a slip hazard. Keep your own balcony safe by moving items that could be damaged and wiping up standing water. In short, occasional overflow is understandable, but repeated leaking is not something you should have to accept. It is a maintenance issue that can and should be fixed.