Published: 28 Oct 2026 · Last verified: 28 Oct 2026 · Next review: Jan 2027 Cost figures are re-checked against permit records quarterly. Changes are logged in Corrections.
In most California cities, the 750 sq ft cliff is a line in a fee schedule plus a paragraph of state law. In San Bernardino, it is a formula written into the municipal code — and it is the clearest one we have published. Section 19.04.030(2)(P)(7)(a) of the city’s development code says in plain ordinance language what every other city makes you infer: an ADU under 750 square feet pays $0 in impact fees; an ADU at or above 750 square feet pays its pro-rata share of the standard new-home fee, computed as the ADU’s square footage divided by the primary dwelling’s square footage, times the per-unit standard. No flat rate like Torrance ($2,243.47), no surcharge stacked on top like Burbank (5% over the pro-rata) — just the ratio.
The six-phase total lands at $316,000*, or $395 per square foot — a modeled floor, not a finished number. The building permit schedule (Attachment “A” of the master fee schedule) is not public, and no dollar figure is published for water/sewer capacity charges on a detached ADU, so both lines are excluded and marked below. The DIF line — about $9,243 — is an arithmetic example built on an assumed 1,500 sq ft primary dwelling, because the ordinance’s formula needs the house size and no public document supplies one for our example. Construction phases 2–6 are carried from the Los Angeles County baseline; San Bernardino does not publish phase-level construction costs.
*Floor, not total — see the caveat below.
The short answer
| 800 sq ft detached ADU · San Bernardino · 2026 | Amount |
|---|---|
| Total build cost (floor — see caveat) | $316,000 |
| Cost per square foot | $395 |
| Largest single line | Systems + interior, $147,000 |
| Building permit + plan check | Verify with city — not in total |
| DIF — pro-rata (arithmetic example) | ~$9,243 (1,500 sq ft house assumed) |
| School district fee (SBCUSD) | $4,304 |
| Water / sewer capacity charges | Verify with city — not in total |
| Pre-approved ADU plans | None found |
The full line-item breakdown
Six phases. The same six used on every build in this series.
| Phase | Cost | Share |
|---|---|---|
| Soft costs (design, school fee, DIF example) | $28,000 | 9% |
| Site work + foundation | $38,000 | 12% |
| Framing + structure | $48,000 | 15% |
| Building envelope | $42,000 | 13% |
| Systems + interior | $147,000 | 47% |
| Landscaping & hardscape | $13,000 | 4% |
| Total (floor) | $316,000 | $395 / sq ft |
Shares rounded. The soft-cost line includes the DIF arithmetic example — see the autopsy.
The honest caveat, same as every city post: San Bernardino does not publish phase-level construction costs, so phases two through six are carried from the Los Angeles County baseline, unchanged — we will not print a number we cannot anchor. What is rebuilt from San Bernardino sources, line by line, is the soft-cost phase. Two fee lines that exist in the city’s code — the building permit and the water/sewer capacity charges — could not be priced from public documents. They are excluded from the total, not estimated. The DIF line is included, but only as the ordinance’s own formula worked through with a stated assumption.
Where San Bernardino differs from Los Angeles
| LA County baseline | San Bernardino | Difference | |
|---|---|---|---|
| Soft costs | $32,000 | $28,000* | −$4,000* |
| Site work + foundation | $38,000 | $38,000 | — |
| Framing + structure | $48,000 | $48,000 | — |
| Building envelope | $42,000 | $42,000 | — |
| Systems + interior | $147,000 | $147,000 | — |
| Landscaping & hardscape | $13,000 | $13,000 | — |
| Total | $320,000 | $316,000* | −$4,000* |
| Per sq ft | $400 | $395* | −$5* |
| ADU permits (HCD) | — | 544, 29th statewide | — |
*San Bernardino’s soft-cost line and total exclude the building permit and water/sewer capacity charges — both real costs, neither priced from public documents — and the DIF line rests on an assumed house size. The −$4,000 gap is an artifact of missing data, not a finding. Do not read it as “San Bernardino is cheaper.”
The fee autopsy
Every fee line we found, with exactly what it is and where it came from.
| Fee line | Amount | Source / status |
|---|---|---|
| Design & engineering | $14,000 | Series baseline, carried — no pre-approved ADU plan program found in city materials (absence not officially confirmed) |
| Building permit | not counted | Master Fee Schedule lists Building & Safety fees as “See Attachment ‘A’” — Attachment “A” not found in any public source. Verify with the city |
| Plan check | not counted | Same — no published rate table. Verify with the city |
| DIF — 7 components, pro-rata | ~$9,243 | (800 ÷ 1,500) × $17,330.78/unit — §19.04.030(2)(P)(7)(a). Arithmetic example: 1,500 sq ft primary dwelling assumed, not confirmed. Standard is the 2022 base, adjusted annually July 15 by the ENR index |
| School fee (SBCUSD) | $4,304 | $5.38/sq ft × 800 — effective 2026-08-03 (prior $5.17). Resolution No. 2025-26-02 (2025-07-22); statutory increase re-adopted 2026-06-02. 500 sq ft and under exempt (Ed. Code §17620) |
| Water — capacity charge | not counted | Ordinance principle confirmed: new detached ADU pays proportional to burden (sq ft or DFU basis). No published dollar figure. Reference only: SBMWD $6,940 for 5/8”×3/4” service (eff. 2026-07-01) — not ADU-applicable as stated |
| Sewer — capacity charge | not counted | Same principle. Reference only: $3,500/dwelling unit + $180 application (2022 base, adjustable March 1) — not ADU-applicable as stated. East Valley Water District service areas use different fees |
| Pre-approved ADU plans | none | None found in city materials; the DCA 25-11 amendment packet mentions none. Adoption of the amendment unconfirmed |
The clearest 750 sq ft cliff in California code
Read §19.04.030(2)(P)(7)(a) and there is nothing to interpret. Subsection (a) does three things in sequence. First, it defines the “impact fees” in play as Mitigation Fee Act (Gov. Code §66000(b)) and Quimby Act (§66477) fees — and explicitly carves out water/sewer connection and capacity charges, which are handled separately in subsection (b). Second, it exempts ADUs and JADUs under 750 square feet entirely. Third, for ADUs at or above 750 square feet, it sets the charge as the ADU’s square footage divided by the primary dwelling’s square footage, multiplied by the standard fee for a new single-family unit. Note: at exactly 750 square feet, the ordinance’s “at or above 750” language would charge, while state law (Gov. Code §66311.5(c)(1)(A)) bars impact fees on ADUs of 750 square feet or less.
That standard is the most itemized in the series — seven lines, published by the Public Works Land Development Division (2022 base, adjusted every July 15 by the ENR index, so treat the base as a floor for the current figure):
| DIF component | Standard (2022 base) |
|---|---|
| Local + regional circulation | $2,667.94/unit |
| Storm drain (detached) | $3,925.91/unit |
| Law enforcement | $639.07/unit |
| Library | $637.89/unit |
| Aquatic facilities | $326.11/unit |
| Public meeting facilities | $1,089.54/unit |
| Parkland & open space (Infill AB1600, detached) | $8,044.32/unit |
| Standard total | $17,330.78/unit |
Work the formula for our example: 800 ÷ 1,500 × $17,330.78 = $9,243.08. That is the number in our total — and the 1,500 sq ft house is our assumption, stated plainly, because the ordinance gives the formula but no example house. A smaller primary dwelling raises the ADU’s share; a larger one lowers it. The 750 sq ft cliff itself needs no assumption: below it, the ordinance says $0. At the site’s 1,600 sq ft default primary size, the same formula gives $8,665.39.
The January 2026 DCA 25-11 amendment packet keeps the same pro-rata structure, so the formula is current through the latest published draft. Final council adoption, however, is unconfirmed.
A utility clause with no dollar figure
Subsection (7)(b) is the rare ordinance that writes the utility principle down and stops. Conversion ADUs built within the existing envelope need no new or separate utility connection and pay no connection or capacity charges. Every other ADU — including new detached — must connect separately and pay connection and capacity charges proportional to the burden the ADU places on the system, measured by floor area or drainage fixture units. A new single-family home built alongside an ADU pays the full standard charges.
The principle is confirmed; the price is not. No published schedule gives the dollar figure for an 800 sq ft detached ADU, so the line sits outside our total. What exists are reference points that are not ADU figures: SBMWD’s Rule No. 5 sets the water capacity charge at $6,940 for a standard 5/8”×3/4” service (effective July 1, 2026, adjusted annually), and the city’s 2022 schedule lists sewer capacity at $3,500 per dwelling unit plus a $180 application fee. Both are general new-connection figures — do not read them as ADU quotes. One more boundary: developments inside the East Valley Water District service area do not use these city/SBMWD figures at all.
$5.38: the top tier, confirmed
San Bernardino City Unified School District charges the state-maximum residential developer fee: $5.38 per square foot, effective August 3, 2026, up from $5.17. The paper trail is complete — Resolution No. 2025-26-02 (July 22, 2025) raising the fee, and a June 2, 2026 board re-adoption of the statutory increase. On 800 sq ft that is $4,304, tying Glendale, Burbank, Fullerton, and Garden Grove for the highest school-fee tier in the series. ADUs of 500 square feet or less are exempt under Education Code §17620; our 800 sq ft example pays on the full area.
No pre-approved plans, and an ordinance still in motion
San Bernardino hands the homeowner no free drawings. The city website, the development code, and the DCA 25-11 amendment materials show no pre-approved or free ADU plan program — the counter is bare, unlike Garden Grove’s four-plan ADU Go or Anaheim’s four-plan ADU Express. Our $14,000 design line stays at the series baseline; no official document confirms the program’s absence, so the qualifier stands.
DCA 25-11 — the ADU ordinance amendment working through §19.04.030(2)(P) — went from a December 2025 Planning Commission recommendation toward the Mayor and Council, with a January 2026 packet preserving the pro-rata DIF formula above. Final adoption is unconfirmed as of publication, and the amendment is the natural vehicle for the city’s SB 1117 response. The January 2027 quarterly review will check for a vote.
A note on SB 1117
Signed September 2026, effective January 2027: for a homeowner’s first two ADUs, impact fees may apply only to square footage above 750, calculated marginally. San Bernardino’s ordinance formula — pro-rata on the whole ADU at 750 and above — cannot survive that math unchanged: an 800 sq ft ADU would owe fees on 50 sq ft of marginal area, not on 800 sq ft scaled by the house ratio. The city will need a revised calculation, and DCA 25-11 is the obvious place for it; we found no mention of SB 1117 in published city materials. School fees are outside SB 1117’s impact-fee definition and stay at $4,304. Whether the water/sewer capacity charges fall inside it is a question of interpretation — it is on our list for the January review.
Disclaimer
Model estimate, not a quote — and explicitly a floor, not a total. The building permit and plan-check rates (Attachment “A” not public) and the water/sewer capacity charge dollars are real costs excluded because they could not be priced from public documents; the DIF line is the ordinance’s confirmed formula worked through with an assumed 1,500 sq ft primary dwelling. Fees change, and the DCA 25-11 amendment may change the code itself. Always verify current fees with the City of San Bernardino Community Development Department before budgeting.
Figures are San Bernardino, 2026. Construction phases 2–6 are carried from the Los Angeles County baseline because the city does not publish phase-level construction costs. The $316,000 total is a floor: the building permit, plan check, and water/sewer capacity charges are excluded because they could not be priced from public documents. The DIF figure (~$9,243) is an arithmetic example using an assumed 1,500 sq ft primary dwelling, not a confirmed quote. This is construction cost information — not a quote, and not legal, engineering, or financial advice. Confirm requirements with the City of San Bernardino Community Development Department and a licensed California contractor.