Published: 31 Oct 2026 · Last verified: 31 Oct 2026 · Next review: Jan 2027 Cost figures are re-checked against permit records quarterly. Changes are logged in Corrections.
Pasadena’s school fee is $2.24 per square foot. Read that again: $2.24. Every other city in this series charges $4.10 to $5.40. On an 800 sq ft ADU, Pasadena Unified takes $1,792 — less than half of what Long Beach ($4,304) or Torrance ($4,304) collect for the same unit. The district simply has not raised its rate in years, and the gap is now the single biggest school-fee spread in our data.
But Pasadena gives with one hand and calculates with the other. Its Residential Impact Fee doesn’t come as a flat number — it’s proportional to your primary dwelling’s square footage, computed by the Public Works Department per project. A 2-bedroom ADU behind a 2,000 sq ft house lands around $11,173 at FY 2026 rates. Behind a 1,200 sq ft bungalow, the same ADU costs considerably less in impact fees. No other city in the series ties the ADU fee this directly to the main house.
Our six-phase total lands at about $310,000, or roughly $388 per square foot — but read the asterisks. Pasadena prices building permits on construction valuation, not a published per-square-foot table, so the exact permit fee requires the city’s calculation. The city does publish official plan-check-plus-permit estimates for its four standard ADU designs ($7,000–$13,000), which anchors our range. Sewer facility charges and water capacity fees for ADUs could not be verified from official sources — marked “verify with city” below.
The short answer
| 800 sq ft detached ADU · Pasadena · 2026 | Amount |
|---|---|
| Total build cost (see assumptions) | ~$310,000* |
| Cost per square foot | ~$388* |
| Cheapest line in the series | School fee, $1,792 |
| Most variable line | Impact fee (scales with house size) |
Phase 1 — Soft costs: the Pasadena ledger
| Line item | Amount | Source / note |
|---|---|---|
| School district fee (PUSD) | $1,792 | $2.24/sq ft × 800; PUSD Developer Fee Instructions rev. 7/1/2025 |
| Residential Impact Fee | ~$11,173* | FY 2026 STFC 2BR rate $27,932 × (800/2,000); Public Works calculates actual |
| Building permit + plan check | $7,000–$13,000* | City-published estimates for standard plans; valuation-based, project-specific |
| Sewer facility charge | Verify with city | PMC 4.53 exists; ADU applicability and amount not verified |
| Water (PWP) | Verify with city | New/changed service at actual cost; no ADU capacity figure published |
| Soft cost subtotal (verified portion) | ~$20,000–$26,000* |
Phases 2–6 (construction) are carried from the series baseline at approximately $285,000; Pasadena does not publish phase-level construction costs.
* Assumptions: 2-bedroom ADU; primary dwelling 2,000 sq ft (impact fee scales with this); mid-grade finishes; FY 2026 fee schedules. Sewer and water capacity charges are the largest unverified items — contact Pasadena Planning & Community Development before budgeting.
Why Pasadena stands out
The $2.24 school fee. Pasadena Unified’s developer fee schedule (revised July 1, 2025) sets residential fees at $2.24/sq ft — against a statewide Level 1 ceiling near $5.17 and series peers at $4.10–$5.40. On 800 sq ft, the spread between Pasadena ($1,792) and Campbell ($4,320) is $2,528 for the same ADU. Districts set their own rates within the state framework; PUSD has simply held its rate flat while others climbed.
The proportional impact fee. Most cities charge ADU impact fees as a flat amount or a fixed per-square-foot rate. Pasadena’s formula — proportional to the primary dwelling — means two identical ADUs on the same street can owe different impact fees. It also creates a planning lever: the fee shrinks as the ratio of ADU to house shrinks. A 7-year affordability covenant (renting at or below 120% AMI) or a landlord agreement (family or city rental-assistance tenancy) can reduce it further — the first covenant-based ADU fee reduction we’ve documented in the series.
The free plans. Pasadena’s ADU Standard Plans Program is the most developed we’ve seen: four designs, two city-designed and free, all pre-reviewed by Building and Safety, with published permit-cost estimates per design. A December 2025 council contract ($100,000) is building an expanded program expected late 2026. For a first-time ADU owner, the combination of free drawings and published fee estimates removes two of the biggest unknowns in the process.
The 750 sq ft cliff
Standard statewide rule, clearly documented: ADUs under 750 sq ft are exempt from the Residential Impact Fee; at 750 and above, the proportional fee applies. Pasadena’s ADU page states this explicitly. Note the school fee has its own, lower threshold — 500 sq ft — below which PUSD collects nothing.
The bottom line
Pasadena is the transparency standout of the series so far: the lowest school fee we’ve published, a published fee estimator per plan design, and free city-designed drawings. The proportional impact fee is the wildcard — price it against your specific house size, not a generic table. At roughly $310,000 all-in, Pasadena sits just under the series middle, built from the most unusual mix of parts we’ve seen.