ADU builders
ADU utility connection: who does what
By the HyreADU research desk. Last checked .
The short answer
An ADU utility connection brings water, sewer and power to the unit.
In California an ADU is not a new residential use for connection fees and capacity charges unless built with a new house (Gov. Code § 66311.5(b)).
For by-right ADUs, the agency cannot require a new separate connection (Gov. Code § 66323). The trench and lines are still real work.
What the law waives, and what it does not
Impact fees are barred on an ADU of 750 square feet or less, but the statute says that does not cover connection fees or capacity charges. Those are a separate line.
For the by-right ADU types in § 66323, the agency may not require a new or separate utility connection between the unit and the utility. For other ADUs, a separate connection may be required with a fee proportionate to the burden.
PG&E’s filed electric tariff says each residential unit must be individually metered, which sits in tension with the statute. Ask the utility early. See ADU utility connections.
Who does the work
A plumber or general contractor runs water and sewer lines. A C-10 electrician runs power and any subpanel. Trenching may be a separate trade. The utility itself does work on its side of the meter. Make sure the contract says who applies to each utility.
Why it breaks budgets
Distance, slope and what is under the yard decide this line, not the size of the ADU. Keep it as its own line in the ADU cost calculator.
What to do next: read the questions to ask an ADU builder, check what decides ADU cost, then tell us about your project. Matching is not live yet, so we reply with information, not a quote.
Get ADU optionsQuestions
Does an ADU need a separate water meter?
Not for by-right California ADUs, unless the agency fits a narrow exception. Ask your water provider.
Can I share the main house’s sewer line?
Often, if it has capacity. See ADU sewer lateral.
Are connection fees waived for small ADUs?
No. The 750 square foot waiver covers impact fees, not connection or capacity charges.
Who pays the utility’s own charges?
Usually the owner. Get them in writing from each utility.
Sources
- Gov. Code § 66311.5 (ADU fees and utility connections). Checked September 5, 2026.
- Gov. Code § 66323 (by-right ADUs, utility connections). Checked September 5, 2026.
- PG&E Electric Rule 16 (service extensions). Checked September 5, 2026.
HyreADU is a publisher. It does not design, permit or build ADUs, has no partner builders, and gives no legal, tax or engineering advice. Rules vary by state and city; California rules are labeled as such.