A contractor’s quote is a price for building. It is not a price for owning the permission to build, connecting to the city, paying the school district, or covering what goes wrong. Those lines arrive after you sign — from the city, the district, the utility, and the county assessor.
This guide lists ten of them, with dollar ranges drawn only from verified sources: our published fee ledgers, the fee items in our dataset marked verified, and the official documents behind them. The model is an 800 sq ft ADU, the same baseline our ledger posts use. Where we could not verify a range, we say so and leave the line out of the total instead of inventing a number.
1. Plan check + building permit: $1,672–$13,798
The most common “permits included” gap. Many quotes include the building permit but not plan check, or quote one city’s number for another city’s job. Verified 800 sq ft figures run from $1,672 in Anaheim (combined plan check + building permit, Tier 3) to $13,798 in La Habra (building permit + plan check + surcharges). Escondido sits in between at $8,562, and Chula Vista prices a standard-plan detached ADU at $3,951 against $4,963 for a custom design. Ask for both halves of this line, separately.
2. Planning / zoning review: $475–$1,865
A separate city desk from the building department, with its own fee. Glendale charges $475 for a planning ADU review; Santa Ana charges $1,865 for an ADU review, with a $571 over-the-counter option and a $504 pre-approved-plan option. Richmond is $1,466 for zoning compliance review. If your quote says “city fees included” without naming this desk, assume it is not included.
3. School developer fees: $2,784–$4,304
School districts charge per square foot, and the 2026 Level I ceiling is $5.38 per sq ft. At 800 sq ft that is $4,304 in districts at the ceiling (Long Beach, Glendale, Torrance, Anaheim) and $2,784 in Baldwin Park at $3.48 per sq ft. ADUs under 500 sq ft are exempt from school fees. This line is collected by the city on the district’s behalf, which is why it rarely appears on a builder’s quote — and why homeowners first meet it at the permit counter.
4. Park, traffic, and fire impact fees: $2,243–$19,521
This is the cliff line. Under current law (Gov. Code §66311.5), ADUs of 750 sq ft or less are exempt from development impact fees; above 750, the fee is proportional to the primary home. Verified flat figures for ADUs above the cliff run from $2,243 in Torrance to $19,521 in Anaheim (police, fire, library, and parks combined). Burbank is $7,078 and Long Beach is $2,366. From January 1, 2027, SB 1117 narrows this line for a lot’s first two ADUs to the square footage above 750 only — an 800 sq ft ADU would be charged on 50 sq ft, not 800. School fees and sewer connection charges are not changed by SB 1117.
5. Sewer capacity / connection: $209–$5,825
Sewer charges split into two different things: a capacity charge for the right to connect, and a connection charge for the physical work. Verified figures run from $209 in Long Beach (an actual ADU permit charge) to $5,825 in Hayward (the FY2026-27 sewer connection charge, effective September 1, 2026). In between: Delta Diablo at $1,702, Simi Valley at $2,232, and Central San at $3,412. Ask your city which of the two you are paying, because a quote that covers the connection rarely covers the capacity charge.
6. Water system development / new meter: $448–$7,222
Water is where a single decision — new meter or shared meter — moves the line by an order of magnitude. Alhambra charges $448 for a utilities improvement fee with no new water meter and $7,222 with one. San Mateo prices water system development at $5.87 per sq ft and wastewater capacity at $5.95 per sq ft for detached ADUs (about $4,700 each at 800 sq ft). If your design adds a meter, price it before you sign, not after the trench is open.
7. Construction tax: $300–$2,000 (flat cities)
Some cities tax the construction itself. Verified flat figures run from $300 in Walnut to $2,000 in Alhambra, with Saratoga at $1.00 per sq ft ($800 at 800 sq ft). Percentage cities are a different animal: San José charges 3.96% of valuation (building and structure tax plus construction-related mitigation). On a percentage city, do not accept a flat allowance — get the valuation basis in writing from the city.
8. Property tax increase: ~$2,200–$3,300 per year
This line never appears on a quote because it is not a construction cost — it is a permanent annual cost. Under Prop 13, only the new construction is reassessed: the assessor adds the ADU’s value to your existing base-year value, and your original house keeps its protection. The planning figure from our published tax guide is about 1.1% of the ADU’s assessed value per year (the 1% base rate plus voter-approved bonds averaging about 0.1%): roughly $2,200 a year on a $200,000 assessed ADU value, $3,300 on $300,000. Your county assessor sets the actual number, and the assessor’s valuation may differ from your construction cost.
9. Contingency reserve: $32,000–$48,000
No contractor quotes this, because it is your money, not theirs. The standard reserve is 10–15% of hard construction cost: $32,000 to $48,000 on a $320,000 build, with our all-in model carrying 12% ($38,400). Hold it in your own account, outside the contract value. If you finish without drawing it, you keep it. A quote that assumes nothing goes wrong is not a plan; it is a hope.
10. Work outside the walls: verify with contractor / city
Trenching and lateral extensions, site survey, and soils reports are real lines that vary so much by lot — distance to the main, slope, soil — that no published ledger supports a statewide range for them. We do not put a number on this line. Get a site-specific figure from your contractor and your city’s public works desk before you sign, and treat any “allowance” for this work as a placeholder, not a cap.
The floor total
Adding only the low ends of the one-time verified lines (1–7):
| Line | Low end |
|---|---|
| Plan check + building permit | $1,672 |
| Planning / zoning review | $475 |
| School developer fees (800 sq ft) | $2,784 |
| Park / traffic / fire impact | $2,243 |
| Sewer capacity / connection | $209 |
| Water development / meter | $448 |
| Construction tax | $300 |
| Floor total (one-time lines) | $8,131 |
That $8,131 is a floor, not a quote: it mixes the lowest verified line from different cities, so no single city charges exactly this, and your city’s stack will be higher. The high ends of the same lines sum to $54,535. On top of either figure, budget the annual property-tax increase (line 8) and hold the contingency reserve (line 9) separately. Line 10 is excluded from both totals because it is unverified.
What to ask before you sign
- Which of lines 1–7 does this quote include, each with a dollar figure?
- Is the school fee in the quote, and at which district’s rate?
- New meter or shared meter — and which water and sewer charges follow from that choice?
- Does “permits included” cover plan check, planning review, and re-checks, or only the building permit?
- What is the contingency, who holds it, and what happens to it if it goes unspent?
A quote that answers all five with numbers is a quote you can compare. Anything else is a starting price with the rest of the project attached later.
Sources
Fee figures are the verified items in our dataset (status: verified) and the published posts behind them: Anaheim plan check and impact fees (verified 7 Oct 2026); La Habra permit and plan check (verified 15 Oct 2026); Glendale planning review (verified 6 Oct 2026); Santa Ana planning review (verified 9 Oct 2026); Baldwin Park, Long Beach, Glendale, Torrance, and Anaheim school rates (verified 6–13 Oct 2026); Torrance and Anaheim impact fees (verified 7–13 Oct 2026); Long Beach sewer capacity, Delta Diablo, Simi Valley, and Central San sewer charges (verified 6–13 Oct 2026); Hayward sewer connection charge, Adopted Master Fee Schedule FY2026-27, effective September 1, 2026 (published post verified 30 Oct 2026); Alhambra utilities improvement fees (verified 19 Oct 2026); Walnut and Alhambra construction taxes and San José 3.96% valuation rate (verified 3–20 Oct 2026). Property-tax figures are from our published guide Will an ADU Raise My Property Tax?; contingency figures from The ADU Contingency Guide; the bid-reading method from How to Read an ADU Bid. Fee law is current Gov. Code §66311.5; SB 1117 takes effect January 1, 2027.