Dear Rabbi, I’m a ben Noach.
When it rains, the water streams from neighbors’ balcony to my grandma’s balcony. So, my uncle and me built a little barrier that stops the water from flooding her property. But I thought that so the water could gather only on her neighbors’ balcony and could cause more damage since, for example, the water could erode some metal/iron components that are present on it. I don’t know if this is sure, but I think it’s possible. What should I do?
The answer to your question really depends on the local laws. Therefore, you should speak to a lawyer, to find out what the local laws are for such a situation.
In the event that there are not local laws, then it depends why the water is running off to your grandma’s balcony. If the building was built this way, then, it is as if your grandma accepted the apartment this way, and you may not block the water from running off. You may however channel the water to run off in a way that won’t damage you grandma’s apartment, but not in a way that damages your neighbor. However, if the neighbor’s balcony was added after the building was built, then he had no right to build it the way he did, because he is now damaging your grandma’s balcony.