Translation:Houses are destroyed
I would think that "Houses are destroyed" translates into "Nyumba zinabomoka", and "Nyumba zinabomolewa" into "Houses are being destroyed".
I believe that "Nyumba zinabomoka" would be more like "houses can be destroyed/are destroyable". The problem is that "Houses are destroyed" can be interpreted in two ways: 1. It can be equivalent to "Houses are being destroyed (right now)." or 2. "Houses are (in a state of having been) destroyed." The first option is translated into Swahili as in this sentence. The second would be "Nyumba zimebomoka," using the present perfect with the stative form of the verb. (I think that is the stative form. Someone please correct me if I'm wrong in any of this.)