Q. I live in a co-op in Morningside Heights. My upstairs neighbors keep plants on their window ledges and fire escape. When they water them, the runoff streams down my windows and into my apartment if the windows are open. I politely asked them to water the plants inside, telling them that the co-op’s house rules prohibit personal items on window ledges or fire escapes. I also wrote a letter to the building’s managing agent and the board. But the problem continues. My neighbors are clearly in violation of building rules, but what about city rules?

A. City life offers few opportunities to flex your green thumb. A fire escape or a window ledge can make for an alluring solution — who wouldn’t want a little box of nature perched outside the window? But if that pretty flowerpot falls off the ledge onto the street below, it could prove deadly for a passer-by, which may explain why your co-op prohibits placing objects on the ledge. A fire escape, meanwhile, is neither a terrace nor a balcony, but an escape route, as its name aptly suggests.

“No one should be using a fire escape for the storage or placement of any items, including plantings,” said Mark A. Hakim, the director of the cooperative and condominium department at the New York City law firm Chaves & Perlowitz. “It is a matter of health and safety.”

Your neighbors shouldn’t knowingly let water leak into your apartment — it’s rude. Manners aside, they are also violating cityand state laws about fire safety that call for keeping means of egress free of obstructions. Keep sounding the alarm — and consider your complaints a public service. Yes, the water could damage your apartment, but a falling object could harm someone, and a blocked fire escape could endanger the lives of your neighbors.

Write another letter to the board and to the managing agent. Demand that the board “take this matter seriously,” Mr. Hakim said. You could also report the blocked fire escape to 311. If an inspector finds a fire hazard, the building would likely be issued a violation. Since you are a shareholder in the corporation, press the board to act before you help inflict fines against your own building. However, a ticket would certainly get management’s attention.