We handle a wide range of earthwork and site development: site preparation, land clearing, rough and finish grading, foundation excavation, drainage solutions, erosion control, driveway and road preparation, retaining wall excavation, and stormwater management. We also perform underground utility excavation including electrical trenching, sewer and water line work, septic line excavation, trenchless pipe repair, and joint trench utility installation for commercial developments. If it involves moving earth or preparing a site for construction, we're likely the right call.

Our primary market is Sonoma County, with particular coverage in Santa Rosa, Windsor, Healdsburg, Petaluma, and Rohnert Park. Our secondary market is Monterey County, including Monterey, Salinas, Seaside, and Marina. We also serve Santa Cruz County, San Benito County, Santa Clara County, and Los Angeles County on qualifying projects. We're headquartered in Windsor, CA — right in the heart of the region we know best.

Yes — electrical trenching is one of the most common requests we receive. Whether it's a short run to a hot tub deck, a longer trench for an ADU connection, or a larger joint trench for a commercial or residential development, we can scope and execute the work. We've completed both short residential trenching jobs and multi-hundred-foot utility trenching projects across mixed terrain. Give us the details and we'll give you a realistic estimate.

Yes. We handle septic system excavation — including full septic and leach field installation for new construction, conversion of septic systems to grinder pump connections tied to city sewer, and related excavation and trenching work. We've also assisted property owners who completed septic tank demolition without realizing a permit and inspection were required. If you need documentation support or have a completed scope that needs to clear a county inspection, reach out and we'll talk through what's possible.

Yes — drainage solutions are a core part of our work, and pooling near a foundation is something we take seriously because the consequences only worsen over time. We install French drains, culverts, drainage ditches, and stormwater management systems designed to redirect water away from structures. We'll assess your property's grading, soil conditions, and water flow patterns before recommending the right approach. Sonoma County's clay soils and Monterey's hillside terrain both create conditions where good drainage design makes a significant difference.

Yes. Retaining wall excavation and associated slope work are things we handle regularly — from residential properties on hillsides to larger commercial and development scopes. We've completed retaining wall and terracing excavation, grading for permitted wall replacements, and full slope stabilization work. If you have county-approved plans and a permit in hand, we can mobilize and execute. If you're still in the planning phase, we can help assess the site conditions.

This is a situation we've encountered before, and we understand how stressful a city notice can feel. Legalizing existing grading and retaining wall work typically requires a grading permit application and may involve a soils engineer review depending on the scope. We can assist with the earthwork side of that process and coordinate with the appropriate professionals to move your project toward permit clearance. Call us to walk through the specifics of your situation.

Yes, in most cases. Sonoma County requires a grading permit for cuts or fills over 50 cubic yards. Monterey County's threshold is 100 cubic yards. Many residential excavation and grading projects — including foundation work, large drainage systems, and significant land clearing — will cross these thresholds. We understand the permit process in both counties and build permit requirements into our project planning from the start so you're not caught off guard.

Creek erosion that threatens a structure is a serious problem, and unfortunately it doesn't improve on its own. We perform erosion control, creek bank stabilization, soil stabilization, and eco-remediation services specifically to address this type of ongoing loss. The right solution depends on the severity of erosion, the soil type, and proximity to the structure — which is why we want to assess the site before recommending an approach. This is exactly the kind of problem we're built to solve.

Yes. We grade and maintain ranch roads, private access roads, and agricultural property roads — including adding gravel to storm-damaged areas, shaping drainage relief to keep roads passable through wet seasons, and preparing surfaces for dust-control product application. After back-to-back atmospheric river events like the ones that dropped over 12 inches of rain on Sonoma County in late 2024, many rural road networks needed significant recovery work. This is a service we're well-equipped to provide on a one-time or annual basis.

Yes. Sewer line connection work for ADU conversions and garage-to-living-space projects is something we see frequently. The scope typically involves locating the existing sewer line, excavating a connection trench, and tying the new unit's sewer line into the main. We're familiar with the permit requirements for this type of work in both Sonoma and Monterey counties and can walk you through what's involved before we start.

Yes. We've completed full site preparation scopes for commercial and development projects — cutting and grading the site, hauling off significant volumes of excess material, building driveway approaches, installing retaining walls and drainage systems, and preparing for foundation work. For commercial developments requiring joint trench and utility coordination, we're experienced with city-approved and stamped plans, gas utility coordination, storm drain and sanitary sewer integration, and inspection sign-offs. We can handle a bundled multi-scope project from start to finish.

Yes. We've drilled piers to bedrock for residential projects requiring foundation support at significant depths. Projects requiring 50 or more piers drilled to 10 to 18 feet are within our capability. Site excavation and grading are often performed in conjunction with pier drilling as part of a unified site prep scope. If you're working with a structural engineer on a foundation design, we're a natural trade partner for the earthwork portion.

Yes. French drain installation is a standard drainage service we provide for residential and commercial properties. Whether you need 50 feet of drain to redirect water away from a house foundation or a more complex system integrating with existing grading, we can assess the site and install a solution built for long-term stability. Drainage done right from the start prevents far more costly problems down the road.

Yes. Land clearing and debris removal — including vegetation, mulch, invasive plants like bamboo, tree stumps, and construction debris — is a routine service we provide. We've cleared properties with substantial bamboo rhizome systems, removed large stumps and brush, and hauled off hundreds of cubic yards of material. If you need a site cleared before construction or grading can begin, we handle that from start to finish including disposal.

Yes. We've provided ballpark estimates for lake and pond dredging — specifically for removing sludge and debris from the lakebed of a man-made lake when the water is drained for seasonal cleanout. If you manage a community lake, retention pond, or agricultural pond that needs sediment removal, reach out with the size and scope and we can assess what's involved.

Yes. We've quoted undergrounding scopes for neighborhood associations that received approval to underground overhead utilities. This type of project requires trenching, conduit installation, coordination with the utility, backfill, and surface restoration — all of which fall within our scope of work. If your community has an approved undergrounding project and needs a contractor to execute the civil work, contact us for a consultation.

Typically we handle site preparation as part of our scope. That said, some clients choose to do light prep work — such as cutting and stacking vegetation, clearing personal items, or providing site access — which can streamline the job and in some cases reduce cost. We'll walk you through any access requirements or pre-work items when we schedule the project. The most helpful thing you can do beforehand is share photos, plans, or any relevant site documents so we can arrive prepared.

Call us at 707-601-9091 or submit a request through the contact page at dw-excavation.com. Share your project details — location, scope, approximate dimensions, photos if available, and your timeline. The more we know upfront, the faster we can give you a useful estimate. We're based in Windsor, CA, and serve Sonoma County, Monterey County, and the broader Central Coast. We'll get back to you promptly.

We're a locally rooted, owner-operated company that has been working in Sonoma and Monterey counties since 2013. Owner Dallas Wohlfeil holds CA General Engineering Contractor License #1060838 and has over a decade of hands-on experience with the local terrain, soil conditions, and permit requirements that make excavation in Northern California uniquely complex. We show up, we communicate clearly, and we do the work right the first time. That reputation is built one project at a time — and we take it seriously.