A hillside wall in Mill Valley has to hold soil, handle winter rain and fit a lot that was never flat. Novara Landscape & Construction designs each wall for the slope, soil and drainage of the site, shows it to you in a 3D rendering first, and builds it with our own crew. We’re a family business working in Marin and Sonoma since 1998.
What Our Customers Say
★★★★★“Novara demonstrated professionalism, reliability, and a strong commitment to quality from start to finish. … Their grading/drainage work was just what I needed to prevent water damage to my home’s foundation.”
★★★★★“Steven and his team were professional, efficient, and exceptionally creative. They took an overgrown mess and turned it into a stunning, usable outdoor retreat.”
What a Hillside Retaining Wall Has to Do in Mill Valley
A retaining wall on a hillside holds back soil that wants to move downhill. In Mill Valley, many homes sit on steep lots, so a wall is often what turns a slope into a usable yard, a safe path or a level spot for a patio. The wall carries the weight of the soil behind it, and that weight gets much heavier when winter rain soaks into the hill.
That is why we don’t start with the wall itself. We start with the site. As Steven put it when describing our work: “We build retaining walls that hold hillsides and elevate landscapes. With 30 years of experience on Marin and Sonoma terrain, we engineer every wall for the specific soil conditions, slope, and drainage of your site.”
- Each wall planned for its own slope, soil and drainage
- A 3D rendering before any digging starts
- Built by Novara’s own crew, not subcontractors
If you already know you want a wall, our page on retaining walls in Mill Valley covers the service itself. This guide is for the planning questions homeowners ask us before they decide.
Signs Your Slope Needs a Retaining Wall
Not every slope needs a wall, and a wall that goes in for the wrong reason can cost more than the problem it fixes. These are the signs that usually mean a wall is the right tool rather than planting or regrading alone.
- Soil or mulch washes down the slope every winter
- An old wall is leaning, cracked or bulging in the middle
- Water collects at the bottom of the slope or against the house
- You want flat, usable space on a hill for a patio, path or garden
What we don’t do: we don’t compete on being the cheapest bid. When a wall is underpriced, corners get cut where you can’t see them, usually in the base and the drainage. We would rather build fewer walls at the right price and build them to last. If a wall isn’t what your slope needs, we’ll say so at the walk-through.
Free estimates and on-site consultations.
Retaining Wall Drainage: Why Hillside Walls Fail
Most retaining walls that fail don’t fail because the stone or block was weak. They fail because water had nowhere to go. When rain soaks into the soil behind a wall, the soil gets heavier and pushes harder. If that water is trapped, the pressure builds until the wall leans, cracks or comes down.
A properly built wall gives that water a path out. That usually means free-draining gravel behind the wall instead of native soil, a perforated drain pipe at the base that carries water away, and a way for water to leave the wall itself. On a hillside, it also means thinking about where the water goes after it leaves, so it doesn’t end up under your patio or against your foundation.
This is the part of the job that gets buried and forgotten, which is exactly why it matters. On a Novara wall, drainage is planned with the wall from the first drawing, because a wall is only as good as what’s behind it.
Do You Need a Permit or Design Review for a Retaining Wall in Mill Valley?
It depends on where your lot is and what the wall does. Homes inside the City of Mill Valley follow the city’s zoning code, which sends some physical improvements, including some retaining walls, through Design Review (see the Mill Valley Zoning Code, Title 20). Many homes with a Mill Valley address, such as Strawberry or Tam Valley, are actually in unincorporated Marin County, and county rules apply instead. The county requires Design Review when a wall doesn’t meet its retaining wall standards (an example of a Marin County design review for a retaining wall).
Height, location on the lot and whether the wall supports a driveway or a building can all change what’s required. A building permit may also be needed for the structure itself.
We check this before the design is final, not after the crew shows up. Steven walks every client through the whole process step by step, starting with permits, then demolition, then the build, so you know what review your wall needs before you commit.
Stone, Boulder, Block or Terraced Walls
The right material depends on the height of the slope, the look of the property and how the wall fits into the rest of the landscape. Novara builds four main types.
Natural stone
Stacked or mortared stone that suits Mill Valley’s wooded, natural setting and ages well.
Boulder walls
Large boulders set into the slope, often used where the wall should read as part of the hillside.
Concrete block
Engineered block systems that give clean lines and work well for taller or straighter walls.
Garden terracing
A series of shorter walls that step up the hill, creating planting beds or level spaces instead of one tall wall.
A wall is often the first step of a larger project. Once a slope is held, the level ground it creates can become a patio or part of one of our full outdoor builds, designed together so the wall, steps, planting and lighting look like one plan.
How Novara Plans and Builds a Hillside Wall
Our process is the same on a single wall as on a full estate, and it’s built so there are no surprises.
- Free on-site consultation. We walk the slope with you, look at the soil, the drainage and how the space will be used, and take photos for the design.
- 3D rendering. Steven designs the wall and shows you a 3D rendering, so you can see the finished hillside before anything is built.
- Step-by-step plan. You get a walkthrough of the whole project in order: permits, demolition, then the build.
- Our own crew builds it. Esteban and Steven’s crew does the work. We don’t hand it to outside subcontractors.
- Walkthrough and warranty. At the end we walk the finished wall with you. All of our hardscape construction, including retaining walls, comes with a 2-year warranty on workmanship. If anything we built fails or doesn’t perform as it should because of our installation, we come back and fix it at no charge.
You can read more about how a Novara project comes together. Novara is run by Esteban Garcia, who started the business in 1998, and his son Steven Garcia Ochoa, who leads design. Clients deal with the family directly, from the first visit to the final walkthrough.
When Planting or Drainage Is Enough Without a Wall
We’d rather tell you a wall isn’t needed than build one you don’t need. Some slopes are better solved another way.
- Light surface erosion. Deep-rooted planting can hold topsoil on a gentle slope. Our planting work uses plants that thrive in Marin’s microclimates.
- Water running off one spot. Sometimes the fix is redirecting water with drainage, not holding soil with a wall.
- A small grade change. A low border or a few steps may solve it without a structural wall.
- A failing wall that’s mostly sound. Depending on what failed, part of a wall may be rebuilt rather than all of it.
We’ll tell you which one your slope needs at the walk-through, and why.
What Drives the Cost of a Retaining Wall on a Slope
There’s no single price for a hillside wall, because two walls of the same length can be very different jobs. These are the things that move the cost the most.
- Height and length. Taller walls hold more soil and need a stronger base. Height usually matters more than length.
- Access. Steep lots with narrow access mean more hand work and smaller equipment, which takes more time.
- Material. Natural stone, boulders and block each cost differently to buy and to set.
- Drainage and excavation. Digging out the base, hauling soil and installing proper drainage is a large share of a well-built wall.
- Review and engineering. Walls that need design review, a permit or an engineer’s design add steps before work starts.
When you compare quotes, ask each contractor: what goes behind the wall for drainage, how deep the base is, whether their own crew builds it, and what the warranty covers. A free estimate from Novara answers all four in writing. No prices on this page: every estimate is written for your site.
Get a Free Estimate for Your Mill Valley Hillside
Tell us about your slope: where it is, what’s happening to it, and what you’d like to use the space for. Photos help. We offer free estimates and on-site consultations, and the family replies to every inquiry directly.
Want to see the service first? Visit our page on retaining wall construction
Hillside Retaining Wall Questions
Do I need a permit for a retaining wall in Mill Valley?
It depends on your lot and the wall. Inside the City of Mill Valley, some retaining walls go through the city’s Design Review; in unincorporated areas with a Mill Valley address, Marin County requires Design Review when a wall doesn’t meet its standards. We check what your wall needs before the design is final.
How much does a hillside retaining wall cost?
It depends on the wall’s height, length, material, drainage and how hard the site is to reach. A tall wall on a steep lot with tight access costs more than a low garden wall. Novara gives a free written estimate after seeing the slope.
How do you keep water from pushing a retaining wall over?
By giving the water a way out. A well-built wall has free-draining gravel behind it and a drain at the base, so rain soaking into the hill doesn’t build pressure against the wall. Drainage is planned into every Novara wall from the first design.
What can you put on a hillside to prevent erosion?
On gentle slopes, deep-rooted planting can hold the soil; on steeper slopes or where soil is moving, terraced or full retaining walls hold it in place. Often the answer is a mix of walls, drainage and planting.
Stone wall or concrete block: which is better on a slope?
Neither is better everywhere. Natural stone and boulders suit wooded, natural settings, while engineered concrete block works well for taller, straighter walls. We’ll show you both in the 3D rendering if you’re deciding.
Does Novara use its own crew?
Yes. Our own crew builds every project, led by the family that has run Novara since 1998. We don’t hand the work to outside subcontractors.
Is Novara licensed and insured?
Yes. Novara holds California C-27 landscaping contractor license #1134876 and carries general liability and workers’ compensation insurance.
Do you build retaining walls outside Mill Valley?
Yes. We build in Tiburon, Belvedere, Corte Madera, Larkspur and across Marin and Sonoma County.
