Drainage Danger — Don’t Let Water Wreck Your Home
What we uncovered this week…
During a recent inspection, we found a failing wood retaining wall beside a pool. It was leaning under pressure, causing soil to shift and the concrete pool deck to lift and crack. If left untreated, it could lead to structural damage to both the pool and the house itself.
During a recent inspection, we found a failing wood retaining wall beside a pool. It was leaning under pressure, causing soil to shift and the concrete pool deck to lift and crack. If left untreated, it could lead to structural damage to both the pool and the house itself.
What went wrong?
Improper support and long-term soil movement on a slope. A structural and soils engineer was recommended to assess and install a proper retaining wall.
Improper support and long-term soil movement on a slope. A structural and soils engineer was recommended to assess and install a proper retaining wall.
This is just one example of what can happen when drainage issues go unnoticed — and we see these problems all the time.
Protect your home from costly water damage — it starts with good drainage.
What Can Go Wrong When Drainage Fails?
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Foundation Damage: Water flowing toward the house can cause cracking and erosion beneath the foundation.
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Soil Erosion on Slopes: Retaining walls can buckle under pressure if improperly built or deteriorating.
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Water Intrusion: Poor grading can direct rainwater or sprinkler runoff into crawl spaces or basements.
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Slab & Patio Issues: Sidewalks and patios installed without proper slope can send water toward — not away from — your home.
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Pool or Landscape Shifting: Shifting soil can cause raised concrete, trip hazards, or even pool damage.
Simple Homeowner Checks to Prevent Drainage Problems
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Walk Your Property After Rain:
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Look for pooling water near the house or retaining walls.
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See if water runs toward the house — it should always drain away.
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Use a Marble or Ball Test:
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Place a marble or small ball on patios or walkways. If it rolls toward your house, your slope may be incorrect.
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Check Sprinkler Lines:
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Watch for soft, soggy spots in the yard even when the sprinklers are off.
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Broken underground lines can create unseen erosion beneath patios and foundations.
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Inspect Retaining Walls:
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Leaning, bulging, or cracking walls are signs of soil pressure.
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Wooden walls often rot over time — they may not be strong enough to support sloped terrain.
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Tips to Get Your Yard Ready for Rain
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Clear debris from gutters and downspouts.
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Ensure downspouts extend away from the home (4-6 feet minimum).
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Re-grade any soil that slopes toward the house.
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Keep plants, mulch, and landscape features away from siding and foundation.
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Seal around exterior windows, siding, and trim.
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Check for patio or concrete additions that block proper drainage.
Have a Slope or Retaining Wall?
If your home is built on a hill, backs up to a slope, or has large retaining walls — now is the time to take a closer look. Small signs of movement can lead to big repair bills down the line.
Considering Selling?
A Pre-Listing Inspection can reveal hidden drainage issues before a buyer’s inspector does — giving you time to fix them and sell with confidence.
Real Advice from 25+ Years of Experience
We’ve inspected over 10,000 of homes across Northern California and see these same issues again and again. Don’t wait for the next storm to discover them.
📞 Need a home inspection? We’re here to help. Call 209-324-3180
Click here to get a PDF version: Drainage Damage Newsletter The Inspector 11.25
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