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ADUs & Utilities

There are many things to weigh when adding an accessory dwelling unit (ADU) to your property. In this post, we'll explore the choices you have when it comes to providing power, water, and sewer to your new dwelling unit. We will touch on how some of the costs depend on if you want to have your ADU’s utilities separately metered or connected directly to the mains that run to the house. We will also discuss some of the advantages and disadvantages of each option.

Four main factors need to be considered when making this decision: cost, timeline, planned use for the unit, and convenience as a landlord. If the ADU is intended for housing family or friends, homeowners often prefer to keep costs down by manually dividing bills or using aftermarket meters for accurate tracking of usage. However, if the unit will be rented out to the community, convenience and responsibility for utility usage become important, and homeowners may be willing to invest the time and expense to separately meter the ADU

If you opt for separate metering, you will need to contact PG&E's Building and Renovation Service Center to initiate the process for a new electric meter. It's crucial to start the application process as soon as you receive your new address assignment during the planning approval process, as there can be significant lead times of up to 10 to 16 months or longer. Additionally, infrastructure upgrades to accommodate the additional usage may be required, and those costs can be passed on to the homeowner.

For electrical, a special consideration will be confirming the size of the main panel to see if upgrading is needed to have enough power to supply a 100amp sub-panel to the ADU. An additional issue arises if your existing main electrical panel sits within thirty-six inches of the gas meter. In these cases the main panel will also need to be moved. This additional expense could be an argument for having the ADU separately metered, so you may want to check out both options to see which is the most cost effective alternative.

One of the main costs for utility connections is trenching, either to main lines that connect to existing utilities or out to the street if you choose to have the unit separately metered. For the latter, you will need an encroachment permit to interrupt the flow of traffic.Encroachment permits can have high costs, depending on what’s required to successfully reroute traffic and for how long, and the work involved in connecting to the main and then repairing the street and curb.

For separate water metering you will need to reach out to the water district that serves your community, but be aware that not only will you have to pay for the work involved with connecting to the main, but you will also be required to pay a connection fee. Thanks to new state law, the connection fee is typically based on a usage/fixture calculation instead of flat fees for single-family residential hook ups. Special considerations include verifying that your main water line is big enough to allow the ADU to draw water from the main house without needing to upgrade the line.

For homeowners who wish to make the construction process as fast, simple, and affordable as possible, the recommendation in the industry is to pull utilities off the house and rely on aftermarket metering to track usage if usage tracking is needed. And if you decide to investigate separate metering but find it overwhelming, know your contractor can be a wonderful resource to help you through the process, and there are consultants you can hire to help get you through the process.

We have included a link below to one that works specifically with PG&E, and can take the pressure off you by providing the information PG&E needs and by keeping the process on track. We have also included a handy Fact Sheet from Ace Resources on the new 2023 code requirements for ADUs.

Link to Ace Resources Fact Sheet for the 2022 California Building Energy Efficiency Standards (Energy Code or Title 24, Part 6) includes requirements for single family and multifamily accessory dwellings units (ADUs).

Consulting service that helps homeowners navigate PG&E utility connections if needed -


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