Excavation works in five stages: site assessment, staking and layout, clearing, bulk digging, and soil compaction. Each stage builds on the one before it, and skipping a step usually means fixing a problem later, often at a higher cost. Here’s what actually happens on a job site, based on how our crews run real projects across the East Valley.
Most guides describe excavation in general terms. We wanted to show what the process looks like from the contractor’s side, using real decisions our crews make on site every week. If you’re planning a project, this breakdown of our excavation services should help you know what to expect before equipment shows up.
For a full look at excavation types, equipment, and cost factors, check out our complete guide to excavation in construction. This article focuses on one question: how does the process actually work, from the first site walk to the final compaction test?
What Is the Excavation Process, Step by Step?
The excavation process is the sequence of steps a contractor follows to turn a raw site into a build-ready surface. It starts with reading the property and ends with a compacted, tested subgrade. In order, the five phases are site assessment, staking, clearing, bulk digging, and soil management, and each one feeds directly into the next.
Phase 1: Site Assessment — Reading the Site Before Anyone Digs
Before a single machine shows up, the crew walks the property. They compare the site plans against the actual ground: existing utilities, slope, soil type, and access points for equipment. In Arizona, that also means checking for caliche depth and drainage patterns, since both can change how a job gets priced and scheduled.
Pro Tip: Ask your contractor what they look for during a site walk. A contractor who only reviews the plans and skips the physical walk-through is more likely to run into surprises once digging starts.
A Job Where Assessment Caught a Problem Early
On a residential pad job in Gilbert, our crew’s site walk turned up something the plans didn’t show: an old septic tank and a buried irrigation line running straight through the planned dig area. Because we caught it during assessment instead of mid-dig, we adjusted the staking and utility locate request before any equipment touched the ground. That’s the value of doing this phase right instead of rushing to the part that looks like progress.
Phase 2: Staking and Layout — Setting the Boundaries
Once assessment wraps up, survey stakes go in. These mark the exact boundaries of the dig area and the target elevations the crew needs to hit. Every equipment operator uses these stakes as their reference point for the rest of the job, so accuracy here matters more than it might seem.
Loose or inaccurate staking causes real problems. If a stake sits off by even a few inches, the whole pad can end up out of spec, and that usually means redoing work that already looked finished.
Did You Know: Before staking begins, Arizona law requires contractors to contact Arizona 811 at least two full working days ahead of digging. This gets underground utility lines marked so the stakes and dig plan avoid them entirely.
Phase 3: Clearing and Site Prep — Getting Down to Bare Ground
With stakes in place, the crew clears vegetation, debris, and topsoil. In Arizona, topsoil removal often means breaking through the first few inches of caliche, the hard mineral layer found under much of the East Valley. This material gets stockpiled for later use or hauled off site, depending on what the project calls for.
This phase looks simple from the outside, but it sets the stage for everything that follows. Uneven clearing leads to uneven digging, and uneven digging means more correction work during compaction.
Phase 4: Bulk Digging — The Main Event
This is the phase most people picture when they think about excavation. Excavators, bulldozers, and scrapers cut the site down to rough grade. Utility trenches for water, sewer, and electrical lines often get opened here too, each cut to the depth its utility requires, with our trenching services crew handling that scope directly.
On a small residential lot, this phase might take a single day. On a multi-acre commercial site, it can run for weeks, especially if the crew hits rock or heavy caliche that needs mechanical breaking instead of standard digging. OSHA’s excavation safety standards also come into play here: any trench five feet deep or more requires a protective system before a crew member can enter it.
Pro Tip: Ask your contractor how they price rock or caliche removal before the job starts. Some estimates assume standard soil conditions and add costs later if the ground turns out harder than expected. A contractor who scopes the site correctly up front avoids that kind of surprise.
Phase 5: Soil Management and Compaction — Finishing the Job Right
Once bulk digging reaches the target elevation, the exposed subgrade gets shaped, compacted, and tested. This step gets rushed more often than any other phase, and it’s the one that causes the most expensive problems later. Loose or poorly compacted soil leads to settling, cracked slabs, and foundation issues months or years after the project wraps.
Compaction is also where excavation hands off to the next phase of the build. Once the subgrade passes testing, the site is ready for grading services to bring it to final finish elevation.
| Phase | What Happens | Typical Duration |
| 1. Site Assessment | Site walk, plan review, utility and soil check | Same day |
| 2. Staking and Layout | Boundaries and elevations marked | Same day |
| 3. Clearing | Vegetation, debris, and topsoil removed | 1 day |
| 4. Bulk Digging | Main earthmoving to rough grade | 1 day to several weeks |
| 5. Compaction | Subgrade shaped, compacted, and tested | 1 to 2 days |
How Long Does the Whole Process Take?
Timelines vary by project size and soil conditions, but most residential jobs move through these five phases in a few days, while larger commercial sites take longer. Caliche, rock, and Arizona’s monsoon season, which officially runs June 15 through September 30, are the biggest factors that stretch a schedule. Our complete guide to excavation types and equipment breaks down cost and timeline factors in more detail if you’re still in the planning stage.
Conclusion
Excavation isn’t just digging a hole. It’s five phases working together, and each one sets up the next. Skip the assessment, rush the staking, or cut corners on compaction, and you’ll pay for it somewhere down the line. Done right, the process gives every trade that follows a clean, accurate surface to build on.
Mirage Excavation LLC runs this process on projects across San Tan Valley, Queen Creek, Gilbert, Mesa, and the rest of the East Valley. If you have a project coming up, contact us for a free estimate. We’ll walk your site, explain what we find, and give you a clear price before any work begins.
Frequently Asked Questions About How Excavation Works
How does excavation work? Excavation follows five phases: site assessment, staking, clearing, bulk digging, and soil compaction. Each phase depends on the one before it, from reading the site plans to compacting the finished subgrade. Skipping a phase usually causes problems later in the build.
What are the 5 phases of excavation, and why does the order matter? The five phases are site assessment, staking and layout, clearing, bulk digging, and soil management. The order matters because each phase relies on accurate work from the one before it. Staking without a proper site assessment, for example, can put stakes in the wrong spot entirely.
Do I need to be present while my property is being excavated? No, you don’t need to be on site the whole time, but it helps to be available during the initial site walk and staking phase. That’s when you can confirm boundaries, ask questions, and flag anything unusual about the property.
What happens if the crew finds something unexpected underground? Work pauses in that area until the crew assesses the find, whether it’s an old utility line, buried debris, or unusually hard soil. A good contractor adjusts the plan and communicates the impact on timeline and cost before moving forward.
Who should I call before an excavation project starts? Call Arizona 811 at least two full working days before digging so underground utilities get located and marked. Then call an experienced local excavation contractor for a site walk and estimate.