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Yard Drainage & Erosion Control in San Diego, CA

Quick answer

Drainage and erosion problems in San Diego usually come from a few heavy winter storms on sloped lots, slow-draining clay, roof water dumped near the house and irrigation runoff. Common fixes include regrading, downspout lines, swales, dry creek beds and slope cover. Canyon-edge slopes may fall under brush management rules, so check with your city first.

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It may seem odd to worry about drainage in a place that gets about 10 inches of rain a year, but San Diego's rain tends to arrive in a few winter storms rather than spread out. Hillside and canyon-edge lots, clay soils that absorb water slowly, and hardened ground after a long dry season can turn one storm into runoff, washouts and water against a foundation. Slopes that lost plant cover to drought, clearing or fire are especially easy to erode.

Signs you have a drainage problem

  • Water pooling against the house or seeping into a garage after storms
  • Gullies, rills or bare soil on slopes
  • Mulch, decomposed granite or soil washing onto walkways and the street
  • Downspouts that dump right next to the foundation
  • Constant overspray or runoff from irrigation, which can cause many of the same problems all year

Common solutions

  • Regrading so soil slopes away from the house toward a safe outlet.
  • Downspout extensions and buried drain lines to carry roof water away from the foundation.
  • Swales and dry creek beds that guide surface water across a yard and slow it down.
  • French drains where soil stays saturated in one area.
  • Rain gardens and rain barrels that hold roof runoff so it can soak in or be used later.
  • Fixing irrigation that waters hardscape or runs too long for the soil to absorb.

Erosion control on San Diego slopes

The goal on a slope is to keep the soil covered and slow the water. Options include erosion-control blankets or straw wattles after grading, deep-rooted shrubs and groundcovers suited to the slope's sun and fire setting, terracing with retaining walls, and redirecting the water that causes the washout. On canyon lots, be careful: some slopes are in brush management zones where permanent irrigation, grading of native soil and certain plantings are restricted. Ask your city before changing a slope that borders open space.

Where the water goes matters

Storm drains in San Diego flow untreated to creeks, bays and the ocean, and the City of San Diego prohibits irrigation runoff onto sidewalks, streets and neighboring property. You also generally can't solve a drainage problem by sending concentrated water onto a neighbor's lot. A good plan sends water to an approved outlet, such as a curb drain where your city allows it, or lets it soak in on your property.

Permits and licensing

Larger grading jobs can need a grading permit, and work on slopes may require an engineer. Thresholds vary by city, so check with your building or engineering department. Drainage systems are on CSLB's list of landscaping work that needs a licensed contractor when the job is $1,000 or more or needs a permit.

Before you hire

  • Take video during a storm so a contractor can see where water goes.
  • Note whether gutters overflow and where downspouts discharge.
  • Ask where the water will end up and how the outlet will be protected from erosion.
  • Confirm the contractor will contact DigAlert (811) before trenching.

Planning around fire rules too? See our fire-safe landscaping guide. If water is threatening a foundation, wall or driveway right now, mark your request as urgent and request a drainage company.

See how it works

How a French drain carries water away from a yard. Press the buttons to run each step and see what happens inside. Made with Colorfigures ·
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Frequently asked questions

Why does my yard flood if it barely rains in San Diego?

Much of the year's rain arrives in a few storms between November and March. Dry, hardened soil, clay and slopes shed that water quickly, and downspouts or irrigation near the house can add to the problem.

Can I send yard water to the street?

Rules vary by city. Storm drains in San Diego flow untreated to creeks and the ocean, and irrigation runoff onto streets is prohibited by the City of San Diego. Ask your city before connecting drain lines to a curb outlet.

How do I stop a slope from eroding?

Keep the soil covered with suitable plants or erosion-control blankets, slow and redirect water coming from above, and terrace where needed. On canyon lots in brush management zones, check what plantings and irrigation are allowed before you start.

Sources and further reading

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