Timeline reality · San Mateo · City of San Mateo Community Development
San Mateo ADU timeline — phase-by-phase, no fairy tales
Most San Mateo ADU contractors quote 6–8 months. Most San Mateo ADUs take 11–15 months from first call to keys. Here is the realistic schedule — feasibility, design, City of San Mateo Community Development plan-check, construction, and finals — with the specific points where projects slip and how we keep ours on track.
City-specific deep dives
- Cost guideSan Mateo ADU cost guide — every line, no surprisesEvery line item, 2026 prices, no surprises. The number you should be quoting from.
- Permits guideHow San Mateo jurisdiction reviews ADU permitsPlan-check workflow, fees, and realistic turnaround for this jurisdiction.
- Timeline guideSan Mateo schedule reality checkPhase-by-phase schedule grounded in active builds, not optimistic Gantt charts.
Phase 1 — Feasibility (1–2 weeks)
Survey, APN pull, zoning confirmation, overlay check, utility scoping, rough budget. In San Mateo this is where we catch the deal-breakers: hillside overlays, easements, undersized panels, sewer issues. Two weeks is realistic; one week is possible on a clean lot.
Phase 2 — Design & engineering (8–12 weeks)
Schematic design, design development, construction documents, Title 24, structural engineering, MEP coordination. San Mateo parcels with overlays or unusual geometry push toward the 12-week end. Weekly homeowner reviews keep this from drifting into 4-month territory.
Phase 3 — City of San Mateo Community Development plan-check (12–20 weeks)
Submittal, first-pass review, comment response, second-pass approval, permit issuance. A clean first submittal in San Mateo is the single biggest schedule lever — it cuts plan-check from 5 months to 3. Overlays and resubmits drive the variance.
Phase 4 — Construction (20–28 weeks)
Foundation, framing, MEP rough-in, inspections, drywall, finishes, fixtures, final inspections. San Mateo construction time is steady; long-pole items are utility upgrades (panel, sewer lateral) and finish lead times. Pre-ordering long-lead items at permit issuance protects this phase.
Phase 5 — Finals, C of O, walk-through (2–4 weeks)
Final building inspection, final MEP inspections, fire clearance, San Mateo Certificate of Occupancy, homeowner walk-through, punch-list, keys. We don't call a project done until C of O is in hand and the homeowner has signed the walk.
San Mateo · Timeline reality
Questions San Mateo homeowners ask about timeline
Direct answers, San Mateo-specific.
Are San Mateo ADU rents really that strong?
Yes — Peninsula tenant demand from the biotech and tech corridors keeps 1BR ADU rents in the $2,800–$3,600 range.Do I need flood-elevation drawings?
Only if your parcel sits in FEMA Zone AE or VE — mostly the eastern edge. We pull FEMA layers at feasibility.Does San Mateo have unique requirements that affect timeline?
Yes — City of San Mateo Community Development sets the local rules, and San Mateo has its own plan-check rhythm. The realistic numbers above reflect 2026 San Mateo conditions, not statewide averages.
Continue researching San Mateo
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