Statistics
ADU utility connection statistics
24 of 42 figures are HyreADU calculations. The statutory thresholds worked as arithmetic, and the share of real permits that lands on each side of them.
Written by HyreADU Research Desk Primary-source research and data analysis
Audited by HyreADU Research Desk Statutory citation and provenance audit
How to use this page
This page publishes no connection-fee dollars, and that is deliberate. No agency publishes a dataset of ADU utility connection charges, and this desk could not retrieve adopted water and sewer fee schedules for its five California jurisdictions.
Reprinting a builder’s figure would be the failure this site exists to avoid.
What can be quantified is the rule itself. Government Code § 66311.5(c)(1) bars any impact fee on an ADU of 750 square feet of interior livable space or less, or a junior ADU of 500 square feet or less.
Above 750, impact fees “shall be charged proportionately in relation to the square footage of the primary dwelling unit” — which is arithmetic, so it can be worked.
Against an 1,800-square-foot house, a 751-square-foot unit carries a 41.7% multiplier where a 750-square-foot unit carries zero.
And the waiver is narrower than it is usually reported. Subdivision (c)(2) defines “impact fee” by reference to § 66000(b) and expressly excludes connection fees and capacity charges.
A waived impact fee and a payable capacity charge are not a contradiction; they are two different pockets, and only one of them is waived for anybody.
Separately, an ADU is not a new residential use. Under § 66311.5(b) a local agency, special district or water corporation may not treat one as a new residential use when calculating connection fees or capacity charges, unless it was constructed with a new single-family dwelling.
How many projects this actually reaches: of 8,536 new-construction ADU permits in Los Angeles, 32.5% are at or below 750 square feet and 67.5% are above it.
Garage conversions sit almost entirely inside the waiver — median floor area 480 sq ft. 24 of 42 figures on this page are HyreADU calculations (24 hyreadu calculation, 18 agency published).
Nothing here is legal or engineering advice, and no figure on this page is a quote for your property.
What this page deliberately does not contain
- No connection-fee, capacity-charge or meter-installation dollars
We could not retrieve adopted fee schedules for water, sewer or electric connection charges across the five HyreADU jurisdictions on the retrieval date.
A number without an adopted schedule behind it is a rumour with a dollar sign, and the whole point of this desk is not to publish those.
When the schedules are retrievable, the table will appear here with a date on it.
- No estimate of how much a service upgrade costs
Whether an existing electrical service must be upgraded comes out of a load calculation performed by a licensed C-10 electrical contractor or an electrical engineer against the California Electrical Code, for the whole property.
There is no square-footage rule and no bedroom rule. Nobody should size a service from a website, and this one will not help them try.
- No resolution of the metering tension
Government Code § 66311.5(d) bars a permitting agency — a category that expressly includes utilities under § 66313(k) — from requiring a separate utility connection for a by-right ADU.
PG&E’s filed Electric Rule 16.B.3.a says electric service “shall be individually metered to every residential unit”. Both stand as retrieved. Which governs a particular application is for the utility, the permitting agency and ultimately the CPUC. We publish the tension rather than tidy it away.
- What it does contain: the rules, quantified
The statutory thresholds are numbers, the proportional fee rule is arithmetic, and the Los Angeles permit file says how many real projects fall on each side of each line. Those three things together are the closest anyone can currently get to an evidence-based answer about ADU utility charges, and they are what is below.
The figures most worth knowing
Full statutory quotations on the utility connections study; the electric-ready analysis on the electrical service study.
Four different charges get called “the connection fee”
- Impact fee
- A development fee under Government Code § 66000(b) — parks, schools, traffic, and the rest. Waived entirely for an ADU of 750 square feet of interior livable space or less and a junior ADU of 500 or less. Above the threshold, charged proportionately to the square footage of the primary dwelling. This is the one everybody has heard of, and it is the only one that is waived.
- Connection fee
- The charge for physically connecting to a water or sewer system. Not waived — subdivision (c)(2) excludes it from the definition of an impact fee. What § 66311.5(b) does instead is bar the agency from treating the ADU as a new residential use when calculating it, unless the unit was built with a new single-family dwelling. That is a rule about the calculation, not an exemption.
- Capacity charge
- The charge for the demand a new connection places on the system as a whole. Treated exactly like the connection fee above: outside the impact-fee waiver, but inside the not-a-new-residential-use rule. This is the charge that most often surprises an ADU budget, because it is invisible until the utility calculates it.
- Meter and service installation
- The utility’s own charge for a new meter or service extension, governed by the utility’s filed tariff rather than by the ADU statute. PG&E’s Electric Rule 16 is the example we read end to end. Whether you can be required to take a separate connection at all depends on which kind of ADU you are building — see the by-right table below.
Why the distinction is worth four paragraphs. “ADUs under 750 square feet are exempt from fees” is one of the most repeated sentences on the ADU internet, and it is wrong in a way that costs money. Read § 66311.5(c)(2) before you budget on it.
The proportional fee ladder, worked
Above 750 square feet, § 66311.5(c)(1) requires impact fees to be “charged proportionately in relation to the square footage of the primary dwelling unit”. That is a ratio, and a ratio can be worked.
Every cell below is a HyreADU calculation of the statutory multiplier — not a fee, and not a schedule from any jurisdiction. Your city supplies the dollars; the statute supplies this number.
| ADU size | Primary 1,200 sq ft | Primary 1,500 sq ft | Primary 1,800 sq ft | Primary 2,400 sq ft | Class |
|---|---|---|---|---|---|
| 500 sq ft | 0% (waived) | 0% (waived) | 0% (waived) | 0% (waived) | HyreADU calculation |
| 600 sq ft | 0% (waived) | 0% (waived) | 0% (waived) | 0% (waived) | HyreADU calculation |
| 750 sq ft | 0% (waived) | 0% (waived) | 0% (waived) | 0% (waived) | HyreADU calculation |
| 751 sq ft | 62.6% | 50.1% | 41.7% | 31.3% | HyreADU calculation |
| 800 sq ft | 66.7% | 53.3% | 44.4% | 33.3% | HyreADU calculation |
| 900 sq ft | 75.0% | 60.0% | 50.0% | 37.5% | HyreADU calculation |
| 1,000 sq ft | 83.3% | 66.7% | 55.6% | 41.7% | HyreADU calculation |
| 1,100 sq ft | 91.7% | 73.3% | 61.1% | 45.8% | HyreADU calculation |
| 1,200 sq ft | 100.0% | 80.0% | 66.7% | 50.0% | HyreADU calculation |
Multiplier = ADU interior livable space ÷ primary dwelling square footage, applied only above 750 square feet. HyreADU calculation from the statutory formula.
It is a multiplier on whatever impact fees your jurisdiction has adopted, and if a jurisdiction has adopted none, the multiplier is applied to nothing. The 500-square-foot junior ADU threshold works the same way.
Use the fee estimator with fee figures you obtained from your own city, and the size envelope calculator to see where your design sits relative to the threshold. Neither tool invents a fee.
How many real projects the waiver actually reaches
The threshold is only interesting if projects land near it. They do — and the median new-build ADU is well above it, which means the proportional ladder in the previous table is the ordinary case for new construction rather than the exception.
| Group | n | Median floor area | Position against 750 sq ft | Impact-fee treatment | Class |
|---|---|---|---|---|---|
| New-construction ADU permits | 8,536 | 920 sq ft | 32.5% at or below | Mostly proportional | HyreADU calculation |
| Garage-conversion permits | 17,937 | 480 sq ft | 75th percentile 745 sq ft — median inside the waiver | Mostly waived | HyreADU calculation |
| Junior ADU permits | 2,238 | 409 sq ft | 76.0% at or below the 500 sq ft junior threshold | Mostly waived | HyreADU calculation |
| New construction at or below 800 sq ft | 3,415 (40.0%) | — | Inside the § 66323 by-right detached size limit | Also protected from a required separate connection under (d) | HyreADU calculation |
HyreADU calculations over 409,619 LADBS permit rows, analyzed 2026-09-05. The floor-area field is the department’s and is a declared value; the full frame rules are on the size digest. The 800-square-foot row is a proxy: the file does not distinguish detached from attached, so it counts permits by size, not by by-right eligibility.
The pattern worth carrying away. The route that most often escapes impact fees is the garage conversion — the cheapest and smallest route, which is half of all ADU permits in this city.
The route that most often pays them is new detached construction, which is also the route most likely to need a service upgrade. The fee structure and the construction reality point the same way.
When a separate utility connection may not be required
The separate-connection exemption is the provision with real money behind it, and it applies to some ADUs and not others. § 66311.5(d) protects the four by-right categories in § 66323 from a required new or separate utility connection. Everything else falls under subdivision (e), which permits one at a charge proportionate to the burden.
| Category | Protected from a required separate connection? | Authority | Class |
|---|---|---|---|
| One ADU and one JADU within the proposed or existing space of a single-family dwelling, with expansion of not more than 150 sq ft | Yes | § 66323 / § 66311.5(d) | Agency published |
| One detached new-construction ADU of not more than 800 sq ft of livable space, four-foot side and rear setbacks | Yes | § 66323 / § 66311.5(d) | Agency published |
| Conversions within an existing multifamily structure — storage rooms, boiler rooms, passageways, attics, basements, garages — at least one and up to 25% of existing units | Yes | § 66323 / § 66311.5(d) | Agency published |
| Up to eight detached ADUs on a lot with an existing multifamily dwelling, or two with a proposed one | Yes | § 66323 / § 66311.5(d) | Agency published |
| Any other ADU | No — a separate connection may be required, at a charge “proportionate to the burden” | § 66311.5(e) | Agency published |
| Any ADU constructed with a new single-family dwelling, or being separately conveyed | No — the (d) protection is expressly disapplied | § 66311.5(b), (d) | Agency published |
| An unpermitted unit constructed before 1 January 2020 | Impact fees and connection or capacity charges not payable, except where infrastructure is required to comply with HSC § 17920.3 | § 66311.7 | Agency published |
Statutory text retrieved from leginfo.legislature.ca.gov on 2026-09-05. Section numbers matter here more than almost anywhere else in ADU law: SB 543 (Stats. 2025, Ch. 520) renumbered § 66324 to § 66311.5 and § 66332 to § 66311.7 with effect from 1 January 2026, and most published guidance on utility charges still cites the old numbers.
“Permitting agency” includes the utility. § 66313(k) defines it as “any entity that is involved in the review of a permit … and for which there is no substitute, including … applicable planning departments, building departments, utilities, and special districts.” That definition is what gives subdivision (d) its reach — and it is the reason the tension with a filed electric tariff is a real one rather than an academic one.
The unresolved metering question
What the statute says
Government Code § 66311.5(d) bars a permitting agency from requiring “a new or separate utility connection directly between the unit and the utility”, or a related connection fee or capacity charge, for the by-right categories in § 66323.
§ 66313(k) puts utilities inside the definition of a permitting agency, so the bar is not limited to city departments.
§ 66311.5(b) separately bars a local agency, special district or water corporation from treating the ADU as a new residential use when calculating connection fees or capacity charges, unless it was constructed with a new single-family dwelling.
What the filed tariff says
PG&E Electric Rule 16.B.3.a, as filed: “For revenue billing, electric service shall be individually metered to every residential unit in a residential building or group of buildings … except as may be specified in Rule 18 and applicable rate schedules.”
Rule 16.C.2: “PG&E will not normally provide more than one Service Extension … for any one building or group of buildings, for a single enterprise on a single Premises.”
Revised Cal. P.U.C. Sheet No. 59584-E, Advice 7572-E, effective 17 May 2025. Retrieved as the filed PDF on 2026-09-05.
Both stand as retrieved, and this desk does not resolve them. Which governs a particular application is a question for the utility, the permitting agency and ultimately the California Public Utilities Commission.
Anyone telling you confidently that your ADU can never be required to take its own meter — or that it always must — is asserting something neither document settles on its own.
PG&E is one of several California electric utilities and this is one filed tariff. A different utility’s rules may read differently, and a water corporation’s rules certainly will. Read your own utility’s filed tariff; they are all public.
The load the Energy Code makes you reserve
Electric-ready reserved load is the utility statistic almost nobody budgets for, and it inverts the usual intuition. Since the 2022 Energy Code, a newly constructed building that installs gas or propane appliances must be made electric-ready for each of them — a dedicated 240-volt circuit and a reserved double-pole breaker space, labeled for future use.
| Gas appliance installed | Reserved 240 V circuit | Class |
|---|---|---|
| Gas cooktop | 50 A | Agency published |
| Gas furnace | 30 A | Agency published |
| Gas water heater (designated heat-pump space more than three feet away) | 30 A | Agency published |
| Gas clothes dryer | 30 A | Agency published |
| Total, if all four are gas | 140 A | HyreADU calculation |
| An ADU classified as an addition (a conversion of existing space) | None — “There are no electric ready requirements for additions or alterations” | Agency published |
Circuit ratings from the California Energy Commission’s 2022 Single-Family Residential Compliance Manual, chapter 10, as tabulated on the electrical service study. The 140-amp total is HyreADU’s sum of the four.
The classification decides everything: the CEC treats a detached, newly built ADU as a newly constructed building and a conversion of existing space as an addition — and only the first carries the obligation.
The consequence for panel capacity. Going all-gas in a new detached ADU does not reduce the demand on the service; it obliges you to reserve 140 amps of 240-volt capacity you are not yet using.
That is the opposite of the intuition most budgets are built on.
Since 49.1% of Los Angeles ADU permits are conversions — and therefore additions — most ADU projects in that city escape the requirement entirely.
Whether your service can carry either scenario is a load calculation, not a website’s guess.
Figures we will not repeat
- “ADUs under 750 square feet pay no fees”
The waiver in § 66311.5(c)(1) covers impact fees. Subdivision (c)(2) defines that term by reference to § 66000(b) and expressly excludes connection fees and capacity charges.
Plan-check and permit fees are not impact fees either. A unit of 700 square feet can be entirely inside the waiver and still receive a substantial utility bill for connection and capacity.
- An average ADU connection fee, for California or anywhere else
There is no such dataset. Connection fees and capacity charges are adopted separately by hundreds of cities, water districts and sanitation districts, on different bases, and are revised on their own schedules.
Every published “average” we have traced originates with a builder describing a handful of their own projects. We would rather print an absence than launder one of those into a statistic.
- The fee ladder quoted as a dollar figure
The multiplier table on this page is a ratio derived from statutory text. It becomes a dollar only when multiplied by the impact fees your jurisdiction has actually adopted, which you must obtain from your jurisdiction. Anyone reproducing our percentages with a dollar sign in front of them has invented the number.
- A confident answer on separate metering
A statute that binds permitting agencies including utilities, and a filed tariff requiring individual metering of every residential unit, both stand as retrieved.
That is a genuine conflict with a real forum for resolving it, and the forum is not a research page.
Anyone who tells you the answer without citing how the conflict was resolved is guessing.
Citing these figures
Journalists and planning desks are welcome to cite these tables. Link the utility connections study for the full statutory quotations and the tariff text, and the electrical service study for the Energy Code analysis.
Where a figure is labeled Agency published, cite the Government Code section, the CEC compliance manual or the filed tariff sheet directly — every one is linked below and every one is readable in a browser.
Where a figure is labeled HyreADU calculation, attribute it to HyreADU and say what it is: “HyreADU calculation of the proportional impact-fee multiplier under Government Code § 66311.5(c)(1)”, or “HyreADU analysis of 8,536 Los Angeles new-construction ADU permits against the 750-square-foot threshold.”
Please carry the exclusion. If one sentence survives from this page into a citation, make it the one about connection fees and capacity charges being outside the impact-fee waiver. It is the most consequential and the most consistently misreported fact in California ADU fee law. Corrections go on the page with a dated note: hello@hyreadu.com.
Questions
Are ADUs exempt from utility connection fees in California?
How much are ADU utility connection fees?
What is the 750 square foot rule?
Does my ADU need its own water and electric meter?
Will I need an electrical service upgrade for an ADU?
Does going all-gas reduce the electrical load?
What about a garage that was converted years ago without a permit?
Why do the section numbers here differ from every other ADU page I read?
Written and audited by
HyreADU Research Desk
Primary-source research, data analysis and fact checking
We are a research desk, not a builder. We read the permit extract, the statute, the HCD return or the fee schedule ourselves, and publish each figure with its source and retrieval date.
Where a number cannot be traced to a primary source, we leave it out and say what we could not verify. Our store-based claims cover California only.
- CA
- the only state this desk will make store-based claims about
- 5
- jurisdictions with extracted ADU permit evidence
- 735
- CSLB-verified companies in the California store
- 0
- national claims from a one-state store
How this desk works
- Primary sources only. Permit counts come from the city or county that issued the permit. Production counts come from HCD’s Annual Progress Report. Rents come from HUD or the Census. We do not cite an article that cites a source; we download the source and compute the figure ourselves.
- This is a California site. The company store is 734 California firms and one New Mexico firm. Permit evidence exists for five named jurisdictions: Los Angeles, San Francisco, Sacramento, San José and unincorporated Marin. A number from that store is titled to those places, never to the United States.
- A permit is not a completion, and a license is not an ADU grade. California licenses no ADU classification. Being named on an ADU permit is evidence of engagement in that jurisdiction, not of quality, completion, or work anywhere else. Owner-builder permits are excluded from contractor counts.
- Calculation is labeled as calculation. Figures we derive are never presented as something HCD, HUD, the Census or a city published. Terner Center research is cited as Terner’s, never restated as ours.
- We do not design, permit or build ADUs, and we take no payment for placement, ranking or a favorable mention. Pages that look like rankings are not: they publish public-record counts and let the reader decide.
- Nothing here is legal, tax or financial advice. Zoning, underwriting and appraisal practice vary by jurisdiction, lender and appraiser. The useful next step on a specific lot is the planning counter and a licensed professional.
Data as of Government Code Chapter 13 sections retrieved from leginfo.legislature.ca.gov 2026-09-05; PG&E Electric Rule 16 (Cal. P.U.C. Sheet No. 59584-E, effective 17 May 2025) retrieved 2026-09-05; LADBS Socrata resource pi9x-tg5x analyzed 2026-09-05. Authorship on this site is organizational: the analysis belongs to the desk rather than to a named individual, and we do not publish credentials we do not hold.
Our editorial policy sets out how we source, date and correct what we publish.
Sources & retrieval dates
- California Government Code § 66311.5 — fees, connection charges and separate utility connections for ADUs , (b) an ADU “shall not be considered … a new residential use for purposes of calculating connection fees or capacity charges for utilities, including water and sewer service, unless the unit was constructed with a new single-family dwelling.” (c)(1) no impact fee at 750 sq ft or less (500 for a JADU); above that, charged proportionately to the primary dwelling. (c)(2) defines impact fee by reference to § 66000(b), excluding connection fees and capacity charges. (d) bars a required separate connection for the § 66323 categories. (e) permits one otherwise, proportionate to the burden. Added by renumbering § 66324 by Stats. 2025, Ch. 520 (SB 543), effective 1 January 2026. Retrieved 2026-09-05.
- California Government Code § 66323 — the by-right ADU categories , The four categories subdivision (d) protects, including the detached new-construction unit of “not more than 800 square feet of livable space” with four-foot side and rear setbacks. Retrieved 2026-09-05.
- California Government Code § 66313 — definitions, including “permitting agency” , Subdivision (k): a permitting agency is “any entity that is involved in the review of a permit … and for which there is no substitute, including … applicable planning departments, building departments, utilities, and special districts.” Retrieved 2026-09-05.
- California Government Code § 66311.7 — unpermitted units built before 1 January 2020 , No impact fees or connection or capacity charges except where utility infrastructure is required to comply with Health and Safety Code § 17920.3. Added by renumbering § 66332 by Stats. 2025, Ch. 520 (SB 543). Retrieved 2026-09-05.
- California Health and Safety Code § 17920.3 — substandard building , The standard § 66311.7 points at: wiring, plumbing, mechanical equipment and fire hazard provisions. Retrieved 2026-09-05.
- Pacific Gas and Electric Company, Electric Rule No. 16 — Service Extensions , Filed tariff. Revised Cal. P.U.C. Sheet No. 59584-E, Advice 7572-E, effective 17 May 2025. B.3.a: “For revenue billing, electric service shall be individually metered to every residential unit in a residential building or group of buildings.” C.2: not normally more than one service extension for any one building or group of buildings. Retrieved 2026-09-05.
- California Energy Commission — 2022 Single-Family Residential Compliance Manual , Chapter 10, electric-ready requirements: 50 A for a gas cooktop, 30 A each for a gas furnace, gas water heater and gas dryer, with reserved double-pole breaker spaces. Section 10.3: “There are no electric ready requirements for additions or alterations.” Summed to 140 A by HyreADU. Retrieved 2026-09-05.
- City of Los Angeles Department of Building and Safety — Building Permits Issued from 2020 to Present (Socrata resource pi9x-tg5x) , The floor-area file behind every exposure share on this page: 8,536 new-construction ADU permits with usable floor area, out of 409,619 rows downloaded and analyzed 2026-09-05. Retrieved 2026-09-05.
- SB 543 (McNerney, 2025) — Accessory dwelling units. Stats. 2025, Ch. 520 , The renumbering that moved § 66324 to § 66311.5 and § 66332 to § 66311.7 from 1 January 2026. Cited because almost all published guidance on ADU utility charges still uses the old numbers. Retrieved 2026-09-05.
Get the schedules in writing
The impact-fee waiver is real and it does not cover connection fees or capacity charges. Ask your city, your water provider and your sanitation district for their current adopted schedules, then do the arithmetic on real numbers.
HyreADU does not design, permit or build accessory dwelling units, does not perform utility work and does not size electrical services. Statistics are informational. They are not legal, tax or engineering advice.
This page publishes no connection-fee or capacity-charge dollars because no retrievable adopted schedule supported them on the retrieval date.
The impact-fee multipliers are HyreADU calculations of a statutory ratio and become a dollar figure only when applied to fees a jurisdiction has actually adopted.
Exposure shares are measurements of City of Los Angeles building permit records and describe no other jurisdiction.
Statutory and tariff text was retrieved on the dates shown; California ADU law was recodified twice between 2024 and 2026 and section numbers change, and a filed tariff may be superseded by a later advice letter.