San Carlos living often means hillside views and sloped lots. When winter storms hit San Diego, that charm can come with drainage and erosion headaches. If you are buying or selling in San Carlos, understanding how water moves on a property helps you protect value and avoid surprises. This guide walks you through practical steps, key warning signs, and the permits and professionals involved so you can plan with confidence. Let’s dive in.
Why San Carlos hillsides need care
San Carlos sits on hilly terrain near Mission Trails Regional Park and Lake Murray, so many homes back to natural or manufactured slopes. Water tends to concentrate in pocket canyons and along slope toes during storms. In our region, long dry periods followed by intense winter rain can cause rapid runoff, erosion, and slope movement when drainage or vegetation is inadequate.
Drainage fundamentals for your lot
Keep water away from slopes and foundations
Start at the roofline. Clean gutters, repair downspouts, and direct runoff into planted areas or approved controls. The City’s Think Blue program shares tips and incentives for smart downspout redirects and maintenance you can do today. Explore the City’s guidance through Think Blue’s tips and resources: Downspout redirects and tips.
Prevent ponding at walls and slope toes
Do not let water collect at the top of a slope or behind a retaining wall. Ponding builds pressure and undermines stability. Properly built walls include drain rock, weep holes, and outlets that must stay clear. For permit thresholds and design paths, see the City’s guidance for retaining walls: Information Bulletin 220.
Simple seasonal checklist
- Clear gutters, downspout strainers, and area drains before the first major storm.
- Extend downspouts into landscaped infiltration areas where feasible.
- Walk the slope after rain, and note any new seepage, bulges, or slumps.
- Keep subdrain outlets and wall weep holes unobstructed.
Erosion control that works on slopes
Temporary controls for rainy season
On newly disturbed soil, simple measures can make a big difference. Fiber rolls, silt fence, erosion control blankets, mulch, and hydroseed help reduce surface wash and buy time for plants to establish. See FEMA’s mitigation guidance on proven slope stabilization tools: Erosion control best practices.
Planting for stability and water efficiency
Deep‑rooted, water‑wise plantings add real holding power to a slope. Avoid overwatering on slopes, which can saturate soils, and steer clear of shallow‑rooted invasive groundcovers. For regional planting and irrigation concepts, this San Diego County landscape manual provides helpful context: Water‑efficient landscape design.
When drainage needs engineering
Interceptor and French drains
When you must collect and convey concentrated flow, solutions like brow ditches, French drains, or protected swales may be appropriate. These should be designed so outfalls do not erode the slope or impact neighbors. The City’s drainage design guidance outlines standards and submittals: Land Development Manual – Drainage Design.
Retaining walls and terraces
Walls over 3 feet in structural height or supporting loads usually require permits and engineered plans. Proper walls incorporate drainage elements to relieve pressure. For submittals and criteria, start here: Information Bulletin 220.
Permits and rules in the City of San Diego
Grading permits and steep hillsides
Most meaningful earthwork on slopes in San Carlos triggers City review. Expect a geotechnical report, drainage study, and the Storm Water Requirements Applicability Checklist (DS‑560) for nontrivial slope changes. Learn the process and steep hillside triggers on the City’s page: Grading permits.
Retaining wall permits
Small decorative walls may be exempt, but many backyard walls need a building permit, especially if they exceed 3 feet or support surcharge. The City outlines standard and engineered paths here: Information Bulletin 220.
State permits that may also apply
If construction disturbs one acre or more, California’s 2022 Construction General Permit applies, including QSD/QSP oversight and a SWPPP. Details are available here: 2022 Construction General Permit. Work that alters a stream channel, bank, or bed requires prior coordination with CDFW’s Lake and Streambed Alteration program: CDFW LSA basics.
Warning signs and what to do
Interior and exterior clues
Watch for new cracks in walls or hardscape, doors and windows that suddenly stick, bulging at a slope toe, fresh slumps on the slope face, leaning fences or trees, or new seepage. These are common red flags of slope distress that call for prompt professional evaluation.
Immediate steps if you see distress
- Prioritize safety and keep people away from the slope or affected area.
- Pause any landscape or grading work that might be adding water or load.
- Contact a licensed geotechnical engineer, and a structural engineer if a wall or foundation is involved.
- If the issue involves a public drainage easement or City infrastructure, contact City Stormwater Services: Stormwater FAQs and contacts.
What buyers and sellers should expect
Who you may need on the team
For most slope or drainage projects, plan for a geotechnical engineer for stability analysis, a civil engineer for drainage design, and a structural engineer for retaining walls. Larger grading projects may also require stormwater professionals under the State’s 2022 CGP: 2022 Construction General Permit.
Timelines, fees, and planning
City plan checks can take weeks to months depending on scope. Grading permits typically run two years with limited extensions. Construction costs vary widely by access, wall type, and engineering; get multiple estimates and use the engineer’s scope to compare bids. The City’s guidance sheets and fee schedules outline submittals and review paths.
How this informs your sale or purchase
If you are selling, gather permits and maintenance records for past walls, drains, and grading, and address simple drainage fixes before listing. If you are buying, pay close attention to slope conditions during inspections, verify permits for visible walls or regrading, and budget for targeted drainage improvements. A clear plan reduces risk and supports stronger negotiating on both sides.
If you want a steady hand to help you weigh hillside risks and prepare a polished strategy for your next move, connect with Dana Rae Stone for a confidential consultation.
FAQs
Do I need a permit for a backyard retaining wall in San Carlos?
- In the City of San Diego, walls over 3 feet in structural height, those supporting surcharge, or similar conditions typically require a building permit. See the City’s criteria and submittals here: Information Bulletin 220.
When is a geotechnical report required for slope work?
- For most meaningful grading on slopes, larger walls, or work in steep hillside areas, the City requires a geotechnical study with your grading permit submittal. Start with the City’s overview: Grading permits.
Can I redirect roof downspouts to the street or storm drain?
- The City encourages directing downspouts into landscaped or approved controls and offers helpful resources via Think Blue. Direct discharge must avoid erosion or nuisance conditions and may require City approval.
Is erosion control required after grading?
- Yes. Disturbed soil and manufactured slopes must be protected with measures like hydroseed, fiber rolls, and erosion blankets until vegetation establishes, which can also affect final approvals.
What should I do if my slope fails after heavy rain?
- Keep people away, stop any water or loading that could worsen conditions, and call a licensed geotechnical engineer. If a City facility or easement is involved, reach out to City Stormwater Services for guidance: Stormwater FAQs and contacts.
