Rain gutters protect your home's foundation. When water sits up against the foundation, it can cause cracking, which can lead to foundation failure over time. Without rain gutters, your home - especially the basement - would flood a lot. Rain gutters divert water away from your home. Rain gutters prevent mold and mildew growth on the roof and siding by moving water away from the home. Rain gutters eliminate the issue of water causing soil erosion in your landscaping, keeping your walkways even and your front yard looking tidy.