I have an issue with a neighbor. His garage wall sits on my backyard fence line. Not considered part of the fence but separates the two properties. He has issues with his foundation due to water damage, water goes into his garage from holes in the wall and foundation when it rains a lot (not visible holes due to below my backyard). My backyard grass is 3 bricks higher than his property line and the grass is flush to his wall. Insurance won't repair any cracks and foundation until the water is stopped. The solution was suggested that i fix my backyard with piping etc to redirect water away from the wall at my expense. Since this is not my garage and doesn't affect me am i obliged to do so? Keeping in mind this is all from heavy rain only. Where do i stand?