Understanding the Hillside Ordinance in the Hollywood Hills

Thinking about buying or remodeling a view home in the Hollywood Hills but keep hearing about the “Hillside Ordinance”? You are not alone. The City of Los Angeles uses special hillside rules to keep slopes stable, protect the landscape, and manage how big and where homes can be built. In this guide, you will learn what the Baseline Hillside Ordinance is, how it affects additions and remodels, what it means for cost and timing, and the steps that help you make a smart decision. Let’s dive in.

What the ordinance covers

The Baseline Hillside Ordinance, often called the BHO, sets development standards for properties in the City’s designated Hillside Areas. It is meant to reduce landslide risk, excessive grading, erosion, and visual bulk on steep terrain. If your lot sits within a Hillside Area and the average slope meets a defined threshold, the BHO applies.

These hillside rules sit on top of your base zoning and the Los Angeles Municipal Code. You must satisfy both planning standards and Building & Safety requirements. If your lot triggers the BHO, you should expect tighter limits on building size and massing, more studies, and added steps in permitting before you can expand or renovate.

How slope and lot size matter

Slope and lot area are two of the biggest drivers of what is possible. A smaller or steeper lot reduces the usable building pad, limits floor area, and increases the need for structural solutions. In effect, the steeper the site, the more restrictive the envelope and the more expensive the build.

Average slope is a key metric for BHO applicability and for how rules are applied. A topographic survey and slope calculation give you the baseline numbers planning and engineering teams will use. Those figures help shape setbacks, grading allowances, and where a house can sit on the site.

Grading, access, and driveways

Grading is carefully controlled in the Hills. Even moderate earthwork requires permits, with larger cuts and fills needing engineered plans and inspections. There are limits on slope gradients and how close earthwork can occur near property lines and public rights-of-way.

Access can be a make-or-break factor in the Hollywood Hills, where private, narrow streets are common. Driveway slope, width, and turnaround space must meet City standards and allow emergency vehicle access. If your road is legally substandard or too tight to improve, expansion can be blocked unless you secure easements or complete costly off-site work.

Setbacks, height, and floor area

Hillside rules often require increased setbacks and stepped or terraced massing to reduce visual bulk. This preserves hillside character and minimizes large flat walls facing the street or canyon. On sloped lots, the method for measuring height matters, since height can be calculated from average or natural grade.

Many hillside overlays set stricter floor area limits than flat neighborhoods. Even if zoning appears to allow more, hillside caps can reduce the total habitable square footage you can add. A design that looks feasible at first pass may need redesign to fit within the allowable envelope.

Retaining walls and foundations

Retaining walls normally require engineered design and permits, with rules that limit height, location, and visual impact. Where large cuts and fills are proposed, you may need walls, tie-backs, and careful drainage.

Foundation systems on steeper lots often include piles, caissons, or grade beams to reach competent soils. These subsurface systems add significant cost and time. In many Hollywood Hills projects, foundation and stabilization can be the single largest construction line item.

Geotech, drainage, and environment

Most hillside projects require a geotechnical and soils report by a licensed professional. The report evaluates slope stability, groundwater, foundation recommendations, and erosion control. Findings from this study can shift your plan, including setbacks from slide areas or the need for remediation.

Stormwater and drainage plans must prevent erosion and manage runoff. Best management practices are common for post-construction maintenance. If your project involves substantial grading or potential environmental impacts, additional review or mitigation may be required.

Trees and landscaping rules

If protected trees or mature native species are present, removal generally requires permits and mitigation. This can affect how you site additions and how much you can clear for views. Landscaping for slope stabilization and visual screening often becomes a condition of approval.

Thoughtful planting choices and restoration of natural contours can help projects move more smoothly. They also reduce long-term erosion and maintenance issues.

Discretionary review and input

Some hillside projects require discretionary review, public noticing, and an opportunity for appeals. In the Hollywood Hills, local Neighborhood Councils and community groups can be active participants. Designs that produce visible scarring, dominate a ridgeline, or significantly alter the streetscape are more likely to draw scrutiny.

Early, open communication and a sensitive design approach can lower risk. Incorporating stepped massing, subdued retaining walls, and careful landscaping can improve your path to yes.

Cost, timeline, and risk

Budget and schedule in the Hills tend to be different from flat-lot projects. Here is what to expect:

• Cost drivers: Geotechnical mitigation, deep foundations or piles, retaining walls, and structural earthwork lead budgets. Off-site work for access, road widening, or public right-of-way improvements can add materially. Carrying costs grow if permitting stretches over months.
• Typical timeline: Preliminary feasibility can take days to a few weeks. A full geotechnical study and permit submittal can run several weeks to months. Administrative reviews often take months, while discretionary reviews or appeals can extend into many months or past a year. Construction on complex hillside structures also takes longer than comparable flat-lot work.
• Risk factors: Unknown subsurface conditions, protected trees, access constraints, or neighborhood opposition can trigger redesign or mitigation. Early technical work and outreach reduce surprises later.

Three early checks

Before you fall in love with the view, confirm three things:

1. Hillside status and slope. Is the property in a designated Hillside Area and does it meet the slope trigger for the BHO? A topographic survey and slope calculation are essential.

2. Geotechnical feasibility. Can a preliminary soils or geologic review support a reasonable foundation approach and grading plan? Big red flags include active slide zones or deep remediation.

3. Access compliance. Can the existing street and driveway meet City standards without significant off-site work or new easements? Emergency access is non-negotiable.

If any of these fail, the value-add plan may not pencil.

Buyer due diligence checklist

Use this checklist to structure your research.

Pre-offer desk checks

• Confirm Hillside Area status and likely BHO applicability based on average slope.
• Verify base zoning and any overlays or specific plans.
• Review recorded easements, access rights, and private road maintenance agreements.
• Pull permit history for past grading, retaining walls, or additions. Treat unpermitted work as a red flag.

After offer: site investigations

• Order a topographic survey with accurate slope calculations and spot elevations.
• Commission preliminary geotechnical reconnaissance for soils and slope stability.
• Conduct title and easement review for restrictions that might limit improvements.
• Check City Planning and Building & Safety files for prior approvals, denials, or open code cases.

Core consultants to engage early

• Civil engineer with Los Angeles hillside experience for grading, drainage, and driveway design.
• Licensed geotechnical engineer or engineering geologist for soils, foundations, and slope stability.
• Architect experienced with the Hillside Design Guidelines and BHO compliance.
• Surveyor for topographic and boundary work used in setback and floor area calculations.
• Structural engineer for foundations and retaining walls.
• Arborist if protected trees are present.
• Land use consultant or attorney if discretionary approvals are likely.

Questions to ask your team

• Geotechnical: Evidence of past slope movement? Likely foundation type? Estimated grading volumes and any required slope remediation?
• Civil and permits: Will the driveway and access meet standards without off-site work? Will the grading plan trigger discretionary review or environmental mitigation?
• Architecture and planning: Given lot size, slope, and access, what envelope is realistic for stories, setbacks, and floor area under the BHO?

Design strategies that help

You can shape a design that respects the hillside and eases approvals. Consider stepped or terraced massing to reduce bulk. Keep retaining walls lower and visually integrated where possible. Protect natural contours and specify landscaping that stabilizes slopes and blends with the setting.

Views matter in the Hollywood Hills, but there is no general legal right to a private view. Still, visual impacts often drive public comment. Designs that minimize scarring and preserve the character of the hillside tend to face less resistance.

When a remodel makes sense

A Hollywood Hills remodel or addition can create significant value, but it requires a clear plan and a realistic budget. Expect higher-than-usual geotechnical and foundation costs, a longer entitlement timeline, and potential public review. If your early checks are favorable, a thoughtful design and a strong consultant team can unlock the potential of a great site.

If you want a quick, grounded read on feasibility or you need a curated search that filters for BHO-friendly lots, the Longfellow + Leach Team can help you align design goals, budget, and timeline.

FAQs

What is the Baseline Hillside Ordinance in Los Angeles?

• It is a set of City rules that govern development in designated Hillside Areas to reduce landslide risk, limit grading, and manage building size and massing on sloped lots.

How do I know if my Hollywood Hills lot is covered by the ordinance?

• Check if the property is in a designated Hillside Area and confirm average slope with a topographic survey; if it meets the slope threshold, the BHO will apply.

How long do permits take for a Hillside remodel?

• Administrative reviews can take months, while projects that need discretionary review or face appeals can extend to many months or past a year, plus added time for construction.

Can I add a second story or expand floor area under the BHO?

• Possibly, but hillside caps on floor area, setbacks, height rules, and stepped massing requirements may limit the size or require redesign to fit the envelope.

What are the biggest hidden costs on steep lots?

• Geotechnical mitigation, deep foundations or piles, retaining walls, and potential off-site access improvements are common cost drivers beyond typical remodel budgets.

Do I need neighbor approval to build in the Hollywood Hills?

• You do not need neighbor consent in most cases, but some projects require public noticing and can be appealed; sensitive design and early outreach often reduce friction.