Excavation & Grading Services in Millbrae, CA
Much of Millbrae is built into the hills. West of El Camino, lots in neighborhoods like the Millbrae Highlands, Telescope Hills and Marina Vista sit on slopes, where a backyard project usually means a retaining wall, a cut into the hillside, or both. Closer to Broadway, the BART station and Highway 101 the ground flattens out, and the work shifts to foundations, utilities and drainage. Harris Excavation handles excavation, grading, trenching and drainage across Millbrae for homeowners, general contractors and developers.
We’re a licensed general engineering contractor (CSLB #1117960) based next door in South San Francisco.
What We Do
- Hillside excavation for additions, ADUs and new homes. Residential excavation
- Retaining wall excavation and backfill, including drain rock placement on tight, terraced lots
- Grading and drainage that moves water away from your house and off the slope safely. Residential drainage
- Utility trenching for water, sewer, storm and electrical lines, including PG&E service upgrades. We’re PG&E Operator Qualified. Residential trenching
- Foundation excavation for new construction and rebuilds
- Erosion control to keep hillside soil in place through the rainy season. Erosion control
Millbrae’s Grading Rules in Plain English
Millbrae’s grading ordinance (Municipal Code Chapter 9.45) requires a grading permit when a project moves more than 50 cubic yards of soil, includes a cut or fill deeper than 2 feet, or disturbs more than 2,000 square feet. Cuts deeper than 5 feet bring in a geotechnical investigation. Some work, such as footing and basement excavation covered by a building permit, can qualify for an exemption.
Timing matters most. Grading generally isn’t allowed between November 15 and April 15 unless the city approves an erosion control plan and a deposit. Erosion control also has to be in place within 30 days after grading stops, or by October 15, whichever comes first. On a hillside lot, that makes late spring through early fall the time to move dirt, so plan to break ground well before mid-November.
Millbrae Project: Retaining Wall Backfill on a Terraced Lot
In 2025 we backfilled three new retaining walls on a terraced residential lot in Millbrae with very little room for equipment. Instead of driving machines into the wall areas, we placed more than 500 tons of drain rock with a CAS AT7 slinger fed by an RL26HD reloader conveyor. We finished in two days, ahead of schedule, and met every geotechnical spec the first time with no rework. Temporary guardrail kept the crew safe at the wall edges, and the owner, geotechnical engineer and neighbors were kept informed throughout. See the full project.
Where We Work in and Around Millbrae
We work throughout Millbrae, from the hillside neighborhoods west of El Camino to downtown Broadway and the BART station area. Nearby, we also serve South San Francisco, San Bruno, Burlingame, Hillsborough and San Mateo.
Millbrae Excavation FAQ
Do I need a grading permit for my yard in Millbrae?
You will if the project moves more than 50 cubic yards, cuts or fills more than 2 feet deep, or disturbs more than 2,000 square feet. We’ll review your scope and tell you where you likely stand before we price it.
Can I grade during the winter?
Generally not between November 15 and April 15, unless the city approves an erosion control plan and a deposit. Most hillside grading is scheduled for the dry season.
Can you get equipment onto a tight hillside lot?
Usually, yes. We use compact equipment, and for backfill we can place material by conveyor or slinger so heavy machines stay out of the wall areas.
Do you work directly with homeowners?
Yes. We work directly for homeowners and as the excavation subcontractor for general contractors and developers.
Get a Millbrae Excavation Estimate
Tell us about your lot and your project. We’ll walk the site, review the plans and soils report, and send a clear written estimate. Request a free estimate