You’ve Got to Know What’s Buried Before You Dig
Utility research isn’t optional—it’s the foundation of any responsible design in California. I’ve seen projects delayed months, budgets blown past six figures, and contractors hit live power lines because someone skipped this step. Call 811 (formerly DigAlert in California), request utility locates, and then do your own homework. That’s the real answer. What follows is how we actually do it at Calichi Design Group.
Call 811 and Request Public Records
California law requires contractors and designers to call 811 at least two business days before any ground disturbance. That’s Government Code §4216.2. When you call, they’ll dispatch a locator who marks public utilities—gas, water, sewer, electric, telecom. But here’s what people miss: the 811 locate is a snapshot. It’s not comprehensive, and it doesn’t cover everything.
After the locate crew marks, file a Public Records Act request with the local water agency, sewer district, and electrical utility. We request as-built plans, easement maps, and service records for the specific parcel. The water district’s records often show hydrants, valves, and mains that aren’t always marked in the field. I’ve pulled plans from the City of Oakland Public Works that showed storm lines running exactly where the client wanted to put a foundation. That early discovery saved real money.
Review County Assessor Maps and Title Reports
The assessor’s parcel map shows recorded easements. We pull this before every project. Easements for utility companies, irrigation districts, or drainage typically indicate where infrastructure runs. Title reports—ordered from a title company, usually 300 to 400 dollars—will list recorded easements and covenants. On a recent project in the Oakland hills, the title report flagged a PG&E easement that ran through the back corner of the lot. The client’s architect hadn’t accounted for it.
Cross-reference the assessor map against the actual site topography. Utilities follow certain paths. Storm drains trend toward natural drainage channels. Sewer lines slope gravity-fed toward outfalls. Gas lines follow street rights-of-way. If you understand the physics and the precedent on neighboring properties, you’ll anticipate where things are.
Visit the Sites of Adjacent Projects
This sounds old-school, but it works. If a house two lots over just had a basement dug, ask the contractor or the GC what they hit. I’ve learned more about East Bay subsurface conditions from jobsite conversations than from any report. Utility depths, soil profiles, water table elevation—this is data you can’t buy. On a Piedmont Avenue project, I talked to a crew doing foundation work next door and learned that perched groundwater sat at 8 feet, well above the regional estimate. That changed our drainage strategy entirely.
Request CEQA Environmental Phase I and Geotechnical Reports
If the property’s had prior development or if there’s a Phase I Environmental Site Assessment on file, those reports often mention subsurface utilities and obstructions. Geotechnical reports go deeper—literally. Soil boring logs show depths where boring rigs hit utilities, which tells you where things are. We’ve pulled old boring logs from county building department records that flagged utility strikes. That’s a clue to location.
For commercial work under California Environmental Quality Act (CEQA) review, check whether an Initial Study or Environmental Impact Report’s been filed. These documents sometimes include utility maps or utility relocation costs that reveal what’s there. The City of San Francisco’s CEQA portal has made this easier; Oakland’s less organized, but it’s still there.
Use Online Mapping Tools and Utility Company Portals
PG&E’s web map (pge.com) shows service territory and some high-level infrastructure. Cal Water, East Bay Municipal Utility District (EBMUD), and most regional water agencies have online GIS portals showing main lines. These aren’t design-grade accurate, but they’re a screening tool. We use them to identify which utilities definitely serve the site and to estimate main locations. On a Walnut Creek project, EBMUD’s GIS showed a 12-inch transmission main 60 feet from the property. That informed our pump station design strategy.
Cities and counties increasingly publish utility maps online. Oakland’s Planning Department GIS includes some storm and sewer layers. The Bay Area’s local agencies responses vary, but it’s worth searching the city’s GIS portal for your project location.
Hire a Professional Locating Service for Complex Sites
For projects with deep excavation, underground parking, or sensitive utilities, we hire a professional utility locating firm. They’ve got ground-penetrating radar (GPR), electromagnetic locators, and experience. GPR can map utilities to 10 feet or more with reasonable accuracy. It costs 2,000 to 5,000 dollars for a site survey, but on a million-dollar project, that’s insurance. California Code of Regulations Title 8 requires utility coordination for excavation work, and having that professional locate report provides legal protection and actual data.
I brought in a locating crew for a Berkeley basement project where the site sat on an old streetcar line. The GPR identified steel conduit and wood framing at 6 feet depth—remnants of the 1920s infrastructure that weren’t on any current map. Without that, the excavation could’ve been chaotic.
Coordinate Early and Document Everything
Once you’ve researched, loop in the utilities directly. For major work, we contact PG&E, water agencies, and sewer districts six to eight weeks before construction. They’ll often send an engineer to walk the site. Their observations about existing conditions are gold. Photograph everything during utility mark-out. Mark the photos with date and GPS coordinates. Build a utility conflict matrix showing what’s where, at what depth, in what size. That document becomes part of your construction plans and clarifies expectations for the contractor.
We follow civil engineering design practices that integrate utility research into early schematic phases, not after 90% design’s done. The California Building Code doesn’t have a single section on utilities—it’s scattered through plumbing, electrical, gas chapters—but California Fire Code §105 and Title 24 both assume utilities are coordinated before construction. If you haven’t researched, you haven’t designed.
Get It Right From the Start
Utility research takes time and money upfront. It saves both later. Call 811, pull public records, review title reports, talk to neighbors, check GIS portals, and hire professionals when the work’s complex. That’s the full sequence we run. Contact Calichi Design Group if you need a utility coordination strategy for your next California project.