Research study
Utility connections: the constraint nobody budgets for
Four different charges get called "the connection fee". State law waives one of them, caps a second, leaves the third alone, and says nothing at all about the fourth.
Written by HyreADU Research Desk Primary-source research and data analysis
Audited by HyreADU Research Desk Statutory citation and retrieval-date audit
The finding
An ADU is not a new residential use, and that single sentence is where most of the money is. Government Code section 66311.5(b) provides that an ADU or JADU “shall not be considered by a local agency, special district, or water corporation to be a new residential use for purposes of calculating connection fees or capacity charges for utilities,” unless it was constructed with a new single-family dwelling.
The 750-square-foot waiver is real, and narrower than it is usually reported. Section 66311.5(c)(1) bars any impact fee on an ADU of 750 square feet of interior livable space or less, and on a JADU of 500 square feet or less.
But subdivision (c)(2) defines “impact fee” by reference to section 66000(b) and expressly excludes connection fees and capacity charges. A waived impact fee and a payable capacity charge are two different pockets, not a contradiction.
Whether you can be made to install a separate meter depends on which kind of ADU you are building. For the by-right categories in section 66323, subdivision (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, subject to two narrow exceptions set out below.
For every other ADU, subdivision (e) permits a separate connection with a fee “proportionate to the burden of the proposed accessory dwelling unit.” We found a live tension we cannot resolve, and we publish it rather than tidy it away. PG&E’s filed electric tariff, Rule 16.B.3.a, requires electric service to be “individually metered to every residential unit”.
That tariff and section 66311.5(d) both stand as retrieved; which governs a particular application is a question for the utility, the permitting agency and ultimately the CPUC.
This edition publishes no per-city water, sewer or school-fee numbers, because we could not retrieve adopted fee schedules on this date. Nothing here is legal, tax or engineering advice.
Read this first
- Your answer is project-specific, and the binding constraint is usually physical, not legal
Every statement below is about what an agency may charge or require. None of it tells you whether the 3/4-inch water service at your curb, the 100-amp panel on your wall or the 4-inch lateral under your driveway can carry a second dwelling.
That is an engineering question answered by a licensed plumber, a licensed electrician and the serving utility on your specific address — and it is the question that decides most budgets. Statute cannot enlarge a pipe.
- We publish no per-jurisdiction fee schedule in this edition
The contract for this page names municipal fee schedules as a dataset. We could not retrieve adopted schedules for the five HyreADU permit jurisdictions on this date, so this edition carries none.
A page that reprints a fee number from a builder’s blog is worse than a page that says it does not have one. See our fee estimator for the structure of the question and the cost study for what we do have.
- One filed tariff is not "the utilities"
We read PG&E Electric Rule 16 in full because it is a public, dated, filed document we could retrieve.
SCE, SDG&E, LADWP, SMUD and several hundred municipal and mutual water systems each file or adopt their own rules, and we have not read them. Do not generalise the PG&E finding to your utility. Ask your utility, in writing, for the rule number.
- Not legal, tax or engineering advice
HyreADU does not design, permit or build ADUs, does not practice law, and does not perform electrical, gas or plumbing work. Nothing here authorizes anyone to touch a service conductor, a gas line or a sewer lateral. Utility connection work is licensed work.
Four charges wear the same name
Ask a homeowner what the utility connection costs and you get one number. Ask a finance director and you get four, because four legally distinct instruments are collected at roughly the same moment in a project and are routinely all called “the hookup fee”. They have different statutory homes, different waivers and different appeal routes.
An impact fee is a development fee imposed under the Mitigation Fee Act, Government Code section 66000 and following, to fund the public facilities a new development burdens — parks, schools, traffic, drainage.
A connection fee or capacity charge is imposed under Government Code section 66013 to recover the cost of the utility capacity a new user consumes.
A meter or service installation charge is a utility charge for the physical apparatus, governed by the utility’s own filed tariff rather than by the Government Code at all.
And a plan-check or permit fee is a cost-of-service charge for reviewing the drawings.
HyreADU analysis: almost every published “ADU fees are waived under 750 square feet” claim is describing only the first of those four, while readers apply it to all four.
Section 66311.5(c)(2) is unusually explicit about this — it defines the waived category by reference to section 66000(b) and then removes connection fees and capacity charges from it by name.
The statute anticipated the confusion and legislated against it, and the confusion survived anyway.
What the statute does to each charge
The four pockets, what section 66311.5 does to each, and the citation as it stands after SB 543 renumbered section 66324 to section 66311.5 with effect from 1 January 2026.
| Charge | Statutory home | What § 66311.5 does | Authority (retrieved 2026-09-05) |
|---|---|---|---|
| Impact fee (parks, traffic, drainage, school) | Mitigation Fee Act, Gov. Code § 66000 et seq. | Waived outright at 750 sq ft of interior livable space or less for an ADU, 500 sq ft or less for a JADU. Above 750 sq ft, “charged proportionately in relation to the square footage of the primary dwelling unit.” | Gov. Code § 66311.5(c)(1) |
| Connection fee | Gov. Code § 66013 (fees for water and sewer connections) | Not waived by the impact-fee provision — subdivision (c)(2) defines “impact fee” by reference to § 66000(b) and excludes connection fees and capacity charges. But it may not be calculated as if the ADU were a new residential use. | Gov. Code § 66311.5(b), (c)(2) |
| Capacity charge | Gov. Code § 66013 | Same as a connection fee. Where a separate connection may lawfully be required, the charge “shall be proportionate to the burden of the proposed accessory dwelling unit … based upon either its square feet or the number of its drainage fixture unit values.” | Gov. Code § 66311.5(b), (e) |
| Separate utility connection or meter | The utility’s own filed tariff or adopted rules | May not be required for an ADU or JADU within the § 66323 by-right categories, unless built with a new single-family dwelling or on separate conveyance. May be required for other ADUs, with a proportionate charge. | Gov. Code § 66311.5(d), (e); § 66323 |
| Charges on an unpermitted unit built before 1 January 2020 | Gov. Code § 66311.7 (renumbered from § 66332 by SB 543) | No impact fees and no connection or capacity charges, “except when utility infrastructure is required to comply with Section 17920.3” of the Health and Safety Code — the substandard-building standard. | Gov. Code § 66311.7 |
| School facilities fee | Education Code § 17620 | Section 66311.5(c)(3) coordinates with the Education Code for units under 500 sq ft. Above the ADU thresholds the school fee follows its own statute and is not waived by Chapter 13. | Gov. Code § 66311.5(c)(3) |
The four charge families and the two special cases, against the operative text of Government Code sections 66311.5 and 66311.7 as retrieved from the Legislative Counsel’s codes service on 2026-09-05.
Citation warning. Section 66311.5 is new. It was added by renumbering section 66324 by SB 543 (Stats. 2025, Ch. 520, § 7), effective 1 January 2026, and section 66324 was itself created out of the repealed section 65852.2(f) by SB 477 in March 2024.
Anything you read citing § 65852.2(f) is two recodifications stale; anything citing § 66324 is one. The substance did not move as much as the number did — but check, do not assume.
The 750-square-foot cliff, worked
A HyreADU calculation, not a fee schedule: what section 66311.5(c)(1)’s proportionality rule produces against an 1,800-square-foot primary dwelling. The statute does not phase in. It waives to 750 and then charges by ratio from the first square foot above it.
| ADU interior livable space | Impact-fee ratio to primary dwelling | Statutory basis |
|---|---|---|
| 400 sq ft | 0% — waived | § 66311.5(c)(1), at or below 750 sq ft |
| 750 sq ft | 0% — waived | The last waived square foot |
| 800 sq ft | 44% (800 ÷ 1,800) | § 66311.5(c)(1), proportional band |
| 1,000 sq ft | 56% (1,000 ÷ 1,800) | § 66311.5(c)(1), proportional band |
| 1,200 sq ft | 67% (1,200 ÷ 1,800) | § 66311.5(c)(1); also the § 66314 detached ceiling |
HyreADU calculation from the statutory formula. Ratios are exact; the underlying fee amount is whatever the jurisdiction has adopted, and this page publishes none.
The design consequence is blunt. Under section 66323(a)(2) the by-right detached unit is capped at 800 square feet anyway. Fifty square feet of extra floor area, taken from 750 to 800, moves an ADU from a full statutory impact-fee waiver into the proportional band.
Whether that trade is worth making depends on fee amounts we have not published — which is exactly why we are not going to tell you which side of the line to build on.
The separate-meter question
The separate-meter question ends more projects than any other, because a new water service or a new electric service means trenching, and trenching is where a budget dies.
What the Government Code says
Section 66311.5(d) applies to the ADUs and JADUs described in section 66323 — the by-right categories.
For those, a local agency, special district or water corporation “shall not require the applicant to install a new or separate utility connection directly between the unit and the utility or impose a related connection fee,” subject to two exceptions: where the unit was constructed with a new single-family dwelling, and where it is being separately conveyed.
Section 66311.5(e) covers everything else. There, a separate connection may be required, and the connection fee or capacity charge “shall be proportionate to the burden of the proposed accessory dwelling unit … based upon either its square feet or the number of its drainage fixture unit values.”
The reach of both provisions is set by section 66313(k), which defines a permitting agency as “any entity that is involved in the review of a permit … and for which there is no substitute, including, but not limited to, applicable planning departments, building departments, utilities, and special districts.” A water district is inside the statute, not outside it.
What one filed electric tariff says
PG&E Electric Rule 16, “Service Extensions”, at B.3 (“Multiple Occupancy”): “In a building with two or more tenants, or where more than one meter is used on the same Premises, the meters normally shall be grouped at one central location.” And at B.3.a, “Residential”: “For revenue billing, electric service shall be individually metered to every residential unit in a residential building or group of buildings or other development with multiple tenants such as, but not limited to, apartment buildings, mobile home parks, etc., except as may be specified in Rule 18 and applicable rate schedules.”
And at 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,” subject to listed exceptions.
HyreADU analysis. Read together, the tariff points toward a meter per dwelling and one service extension per premises; the statute bars a permitting agency from requiring a separate connection for a by-right ADU. We do not think a research page should declare which wins.
What we will say is that the question is a real one, that it is answerable in writing, and that the written answer is the document to get before the budget is signed.
How to get a real answer for your address
The reproducible method. It is administrative, not technical, and it costs nothing but letters.
- 1 Establish which section 66323 category your unit falls in
A conversion inside existing space, a detached unit of not more than 800 square feet with four-foot side and rear setbacks, a conversion inside an existing multifamily structure, or a detached unit on a multifamily lot — these are the by-right categories, and they are the ones section 66311.5(d) protects.
An ADU that is none of them falls under subdivision (e) instead, where a separate connection may lawfully be required. Everything downstream depends on this answer.
- 2 Ask each permitting agency for its rule number in writing
Not “what will this cost”. Ask: under which adopted fee schedule or filed tariff rule is the charge imposed, and on what date was it adopted?
Section 66313(k) puts utilities and special districts inside the definition of a permitting agency, so the question is properly addressed to the water district and the sanitation district as well as to the building department.
- 3 Separate the impact fee from the connection fee on paper before you argue about either
A counter conversation that conflates them cannot be won. Ask for the fee line items itemized by statutory authority — Mitigation Fee Act fees under section 66000 in one column, connection and capacity charges under section 66013 in another. The waiver in section 66311.5(c)(1) applies to the first column only.
- 4 Get a licensed professional to assess the physical service before you get attached to a design
A licensed plumber on the water service and lateral, and a licensed C-10 electrical contractor on the panel and service. Their answer sets the real budget. Our electrical service study sets out what the load calculation is actually doing, and our septic study covers the unsewered case.
- 5 If the unit was built before 1 January 2020 without permits, read section 66311.7 first
The charging rules are different and much more favorable: no impact fees and no connection or capacity charges “except when utility infrastructure is required to comply with Section 17920.3” of the Health and Safety Code. That is a health-and-safety carve-out, not a general escape hatch, and the substandard-building standard it points at is a real one.
The words that decide the invoice
- Impact fee
- A development fee within the meaning of Government Code section 66000(b), as applied by Government Code section 66311.5(c)(2) — which then excludes connection fees and capacity charges from the term for the purposes of the ADU waiver. If a charge is a connection fee or a capacity charge, the 750-square-foot waiver does not touch it. Retrieved 2026-09-05.
- Capacity charge
- A charge for the utility capacity a new user consumes, imposed under Government Code section 66013. Where section 66311.5(e) permits one on an ADU it must be “proportionate to the burden of the proposed accessory dwelling unit … based upon either its square feet or the number of its drainage fixture unit values.” Note the alternative: square feet or fixture units, not both, and not per-dwelling.
- Permitting agency
- “Any entity that is involved in the review of a permit for an accessory dwelling unit or junior accessory dwelling unit and for which there is no substitute, including, but not limited to, applicable planning departments, building departments, utilities, and special districts.” Government Code section 66313(k). The definition exists so that a water district cannot impose what a planning department could not.
- Interior livable space
- The measure the 750-square-foot and 500-square-foot thresholds are drawn against in section 66311.5(c)(1). It is not the same as gross floor area, and the difference — wall thickness, mechanical closets, a stair — can be the difference between a waived fee and a proportional one. Confirm which measure your building department applies before you draw to the line.
- Drainage fixture unit
- A plumbing-code loading value assigned to each fixture, used to size drains and, under section 66311.5(e), as one of the two permitted bases for a proportionate sewer capacity charge. A one-bedroom ADU carries far fewer fixture units than a house, which is precisely why the statute offers it as an alternative to a flat per-dwelling charge.
Where the licensed professional is not optional
Everything on this page is about who may charge what. None of it is about how to do the work, and this page will not tell you how to do the work.
Connecting a dwelling to an electric service, a gas main, a water main or a sewer lateral is licensed work in California. Electrical service and panel work is the province of a licensed C-10 electrical contractor; water, gas and sewer connections belong to a licensed C-36 plumbing contractor; the utility’s own crews do the work on their side of the point of delivery.
The failure modes here are not inconvenient, they are lethal or catastrophic: back-feeding an unbonded neutral, an unpurged gas line, a cross-connection between potable and non-potable water, a lateral tied into a storm drain. A homeowner who wants to save money on an ADU should save it in the design, not in the trench.
HyreADU recommendation: book the utility’s own service-planning appointment before you commission drawings. Most utilities will tell you what capacity exists at your address at no cost, and that answer reorders a project’s economics more than any fee waiver on this page.
What we could not verify
Adopted fee schedules for the five HyreADU permit jurisdictions. The page contract names published municipal permit, plan-check, school, park, traffic and utility connection fee schedules as a primary dataset.
We did not retrieve them on this date and this edition therefore publishes no fee amounts. This is a stated gap, not an oversight, and it is the first thing the next edition should close.
Filed tariff rules beyond PG&E. We read PG&E Electric Rule 16 in full from the filed tariff PDF.
We did not read the equivalent rules for Southern California Edison, San Diego Gas & Electric, LADWP, SMUD, or any water or sanitation district.
The apparent tension we report between section 66311.5(d) and Rule 16.B.3.a may resolve differently under a different utility’s rules, or may not arise at all.
How any agency actually resolves that tension. We found no CPUC decision, HCD letter or published guidance addressing the interaction directly, and hcd.ca.gov returned HTTP 403 throughout this retrieval so we could not check HCD’s technical assistance material.
We therefore report the tension and stop. We do not tell you that your utility’s meter requirement is unlawful, and you should be suspicious of any page that does.
Whether a given jurisdiction measures “interior livable space” the way you do. The 750-square-foot threshold is statutory; the measuring convention applied at a counter is local practice. We have not surveyed it.
Questions
Are ADU utility connection fees waived in California?
Does an ADU need its own water meter?
Does an ADU need its own electric meter?
How is an impact fee calculated on an ADU over 750 square feet?
What about a sewer capacity charge — can it be charged per dwelling?
I have an unpermitted unit from before 2020. What do I pay?
Which Government Code section should I cite for ADU fees?
Can I do the utility connection work myself to save money?
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, Advice 7572-E, effective 17 May 2025) retrieved as filed PDF and text-extracted 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 , Key retrieved text: (b) an ADU or JADU “shall not be considered by a local agency, special district, or water corporation to be 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 of interior livable space or less (500 for a JADU); above that, “charged proportionately in relation to the square footage of the primary dwelling unit.” (c)(2) defines impact fee by reference to § 66000(b), excluding connection fees and capacity charges. (d) bars a required new or separate utility connection for the § 66323 categories. (e) permits one otherwise, with a charge “proportionate to the burden.” Added by renumbering § 66324 by Stats. 2025, Ch. 520, Sec. 7 (SB 543), effective 1 January 2026. Retrieved 2026-09-05.
- California Government Code § 66323 — the by-right ADU categories , The four categories that section 66311.5(d) protects: one ADU and one JADU within the proposed or existing space of a single-family dwelling with expansion of “not more than 150 square feet”; one detached new-construction ADU of “not more than 800 square feet of livable space” with four-foot side and rear setbacks; conversions within existing multifamily structures (“storage rooms, boiler rooms, passageways, attics, basements, or garages”), at least one and up to 25 per cent of existing units; and up to eight detached ADUs on a lot with an existing multifamily dwelling, or two with a proposed one. 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 for an accessory dwelling unit or junior accessory dwelling unit and for which there is no substitute, including, but not limited to, applicable planning departments, building departments, utilities, and special districts.” Subdivision (a) defines the ADU itself and expressly includes a manufactured home as defined in Health and Safety Code § 18007. Retrieved 2026-09-05.
- California Government Code § 66311.7 — unpermitted units built before 1 January 2020 , A local agency “shall not deny a permit for an unpermitted accessory dwelling unit or an unpermitted junior accessory dwelling unit that was constructed before January 1, 2020” except where “correcting the violation is necessary to comply with the standards specified in Section 17920.3 of the Health and Safety Code”; inspectors “shall not penalize an applicant”; and the homeowner “shall not be required to pay impact fees or connection or capacity charges except when utility infrastructure is required to comply with Section 17920.3.” Added by renumbering § 66332 by Stats. 2025, Ch. 520, Sec. 9 (SB 543), effective 1 January 2026. Retrieved 2026-09-05.
- California Health and Safety Code § 17920.3 — substandard building , The standard section 66311.7 points at. Subdivision (d) covers “all wiring, except that which conformed with all applicable laws in effect at the time of installation if it is currently in good and safe condition and working properly”; (e) covers plumbing on the same pattern, “free of cross connections and siphonage between fixtures”; (f) covers mechanical equipment including vents; (h) covers fire hazard. Retrieved 2026-09-05.
- California Government Code § 66314 — the maximum standards a local agency may apply , Used here for the size ceilings the fee ladder runs against: an attached ADU’s “total floor area … shall not exceed 50 percent of the existing primary dwelling”, and “[t]he total floor area for a detached accessory dwelling unit shall not exceed 1,200 square feet.” Retrieved 2026-09-05.
- California Government Code § 66321 — size and height standards a local ordinance may not impose , The floor beneath local size limits: no maximum below 850 sq ft of interior livable space, or 1,000 sq ft for a unit with more than one bedroom; and no standard that “does not permit an accessory dwelling unit with at least 800 square feet of interior livable space and with four-foot side and rear yard setbacks to be constructed.” Relevant because the fee ladder and the size floor interact. 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, cancelling Revised Cal. P.U.C. Sheet No. 47819-E; Advice 7572-E, submitted 17 April 2025, effective 17 May 2025. B.3 “Multiple Occupancy”: meters “normally shall be grouped at one central location”. B.3.a “Residential”: “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.” 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.” Retrieved as the filed PDF and text-extracted on 2026-09-05. Retrieved 2026-09-05.
Ask the utility before you draw the plans
The statute settles who may charge you. Only the serving utility can tell you whether the service at your address can carry a second dwelling — and that answer moves budgets far more than any fee waiver on this page.
The feasibility checker asks the questions that surface it, and it will never tell you that you can build.
HyreADU does not design, permit or build accessory dwelling units, does not practice law, and does not perform electrical, gas or plumbing work. This page is informational and is not legal, tax, financial or engineering advice.
It describes California statutory text and one filed utility tariff as retrieved on 5 September 2026; it publishes no jurisdiction’s fee amounts, and it does not tell you that any particular charge on your project is lawful or unlawful.
Utility connection work is licensed work in California — a licensed C-10 electrical contractor for electrical service, a licensed C-36 plumbing contractor for water, gas and sewer.
Nothing here should be read as instruction to perform that work. The useful next steps are the permitting agency and the serving utility, both in writing.