Even perfect gutters can fail you if the downspouts dump water right next to the house. In Bay Area winter storms, that runoff can overwhelm soil, flood crawlspaces, stain siding, and accelerate foundation settling.
This guide breaks down practical drainage upgrades—from simple extensions to underground drain lines—so your roof water ends up where it belongs: away from the structure.
Start with a simple diagnostic
- Do you see erosion channels beneath downspouts?
- Does water pool near the foundation after rain?
- Are there overflow marks on gutters during heavy storms?
- Do downspouts discharge onto hardscape sloping toward the house?
Option 1: Downspout extensions
Best for: quick improvement when you just need more distance.
- Direct water at least several feet away from the foundation.
- Avoid directing runoff onto a neighbor’s property or public walkways.
- Secure extensions so they don’t disconnect during storms.
Option 2: Splash blocks and rain dispersal
Best for: soil areas where you want to prevent erosion at the discharge point.
- Use a splash block or rock bed to slow water and protect soil.
- Make sure the area has a clear path to drain and won’t become a “pond.”
Option 3: Underground drain lines
Best for: lots with limited space or where extensions are a tripping hazard.
- Water is routed through piping to a safe discharge point.
- Proper slope is critical; flat runs can hold water and clog.
- Include cleanouts so the line can be serviced.
Option 4: Add more downspouts
Best for: long gutter runs or roof valleys that dump a lot of water in one spot.
- More downspouts reduce the “rush” that causes overflow at corners.
- They also reduce standing water in gutters, which improves longevity.
Option 5: Grading and surface drainage
Downspout work won’t solve everything if the ground slopes toward the home. Improving grading and surface drainage can be the difference between “better” and “fixed.”
Common mistakes to avoid
- Dumping downspouts right next to the foundation.
- Sending water onto hardscape that slopes back toward the home.
- Underground drains with no cleanouts.
- Connecting roof drains into systems that can back up during storms.
Want a complete gutter + drainage setup?
We can evaluate gutter sizing, slope, downspout placement, and drainage routing together. Visit gutters or contact us for an estimate.