What site drainage is supposed to do
Every site needs a plan for rain, irrigation, and roof runoff. Finished grades should slope away from the foundation, and paved surfaces should carry water toward drains or open areas instead of toward walls. Codes set minimum slopes away from foundations, and drainage plans add detail for each site.
Surface drainage works with collection systems. Area drains, catch basins, downspout connections, swales, and subsurface drains carry water to an approved outlet. Each part depends on slope, capacity, and a clear discharge point. Subsurface drains behind retaining walls and foundations work only if they are sloped, protected from clogging, and connected as designed.
Landscaping changes the picture over time. Planters against walls, soil raised over weep screeds, irrigation overspray, and later hardscape can reverse grades that once worked. Separating original construction from later changes is often central to a drainage investigation.
How drainage defects show up
Drainage problems often appear somewhere else first. Efflorescence on foundation walls, damp slabs, and water in crawl spaces can all trace to water held against the building. So can settled flatwork and decay at the base of siding.
Common conditions include negative slope toward the foundation, downspouts discharging at the wall, and area drains set above the surrounding grade. Drain lines may be crushed, disconnected, or never connected to an outlet. Inadequate clearance between soil and cladding can let moisture reach the wall assembly.
On hillsides and in expansive soils, water management also affects how the ground behaves. Those questions may call for review by a licensed design professional alongside the construction review. A clear record of grades, drains, and water patterns gives that review a sound starting point.
Investigating grading and drainage
A typical investigation measures slopes around the building and across paved areas, compares them with the grading and drainage plans, and maps where water collects. Elevations at drain grates, thresholds, and weep screeds show how the pieces relate. Flow testing with water shows whether drains accept and carry water as intended.
Camera inspection of drain lines can locate breaks, sags, root intrusion, and disconnected fittings without excavation. Observations during or soon after rain add evidence that dry-weather testing cannot.
We use state-of-the-art cameras and video documentation techniques to provide trial-ready exhibits. Our field reports pair that photo documentation with clear descriptions of each condition.
SB800 and repair planning
For many California homes, SB800 includes standards addressing drainage systems and hardscape installed as part of the original construction. We are educated on past and current building codes and SB800.
We prepare conceptual repair scopes and cost estimates. Drainage repairs can range from regrading and downspout extensions to new collection systems. A clear scope lets the parties compare them on the same facts.
Repairs also need to account for everything that drains into the system. Roofs, paved areas, and neighboring slopes all contribute flow, and an outlet that cannot accept the volume will back up no matter how many inlets are added.
Common warning signs
- 01Water ponding next to the foundation after rain
- 02Soil or mulch built up against siding or stucco
- 03Efflorescence or dampness on foundation walls and slabs
- 04Water or mud in crawl spaces
- 05Downspouts discharging at the base of walls
- 06Settled, cracked, or back-sloped hardscape
- 07Area drains that stand full or overflow