ADU MEP Services | Mechanical, Electrical, Plumbing & Title 24

Residential MEP Plans — Single-Family Homes

Mechanical, Electrical & Plumbing for new construction, additions, and remodels, from $1,495.

Full MEP Package — Mechanical, Electrical & Plumbing

All three disciplines coordinated by one team — the best value for most ADUs, from $2,295.

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What is included in a Full MEP Package? The Full MEP Package is a single, coordinated, permit-ready set covering all three engineering disciplines for your California ADU… Read more Why order Mechanical, Electrical, and Plumbing together? Ordering Mechanical, Electrical, and Plumbing together as the Full MEP Package gives you two things three separate orders cannot:… Read more How much does a Full MEP Package cost? The Full MEP Package starts at $1,495 for an ADU up to 600 square feet and scales with the size of the unit up to $2,595 for… Read more Are city corrections included? Yes. Read more How long does a Full MEP Package take? Our standard turnaround for the Full MEP Package is 5 business days, included at no extra cost, measured from receipt of your… Read more Can I add Title 24 to my MEP order? Yes — a Title 24 energy compliance report is a flat +$240 add-on to any MEP order, including the Full MEP Package, at any ADU… Read more

ADU Mechanical (HVAC) Plans

Heating, cooling, ventilation, and equipment schedules designed to California code, from $995.

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What is a mechanical plan for an ADU and what does it show? A mechanical plan for an ADU is the permit-ready drawing set that documents the complete HVAC and ventilation design — the… Read more What HVAC system is most commonly used in California ADUs? The most common HVAC system in California ADUs is the ductless mini-split heat pump — a two-piece system with one or more indoor… Read more What is a heat load calculation and why is it required? A heat load calculation — performed using the ACCA Manual J method recognized by California building codes — determines the exact… Read more Does California require separate mechanical permits for ADUs? An ADU's mechanical work nearly always requires permitting, but whether it is issued as a separate mechanical permit or rolled into… Read more What are the Title 24 requirements for HVAC in new California ADU construction? Title 24 — California's Building Energy Efficiency Standards — governs the HVAC system in every new ADU. Read more Can multiple mini-split heads share one outdoor unit? Yes. Read more What are the ventilation requirements for a new ADU in California? Every new ADU in California must include a continuous, whole-building mechanical ventilation system meeting ASHRAE 62.2 —… Read more What happens if HVAC is installed differently than shown on approved plans? If HVAC is installed differently than the stamped, approved plans, the work can fail inspection and the permit cannot close until… Read more What is included in a mechanical equipment schedule? A mechanical equipment schedule is the table on the plan set that lists every HVAC and ventilation component with the data a plan… Read more Do I need a mechanical plan for a garage conversion if the garage already has a heater? Almost always, yes. Read more How do all-electric mandates affect mechanical plans? In California cities that have adopted all-electric "reach codes," gas-burning HVAC is prohibited in new ADU construction — meaning… Read more

ADU Electrical Plans

Panels, load calculations, lighting, circuits, and EV-ready provisions, from $995.

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What is included in the electrical plans for an ADU? Our ADU electrical plans are a permit-ready drawing set — typically sheets E-0 through E-2 — that gives your city's plan reviewer… Read more What panel size does an ADU need in California? The honest answer is: whatever a formal NEC Article 220 load calculation says — not a guess based on square footage. Read more What is an electrical load calculation and why is it required? An electrical load calculation — performed under NEC (and CEC) Article 220 — is the standardized method for determining how much… Read more Does my existing main panel need to be upgraded to add an ADU? Maybe — and the only reliable way to know is a formal NEC Article 220 load calculation that adds the new ADU load on top of your… Read more Does California require ADUs to be wired for EV charging? In most California ADU projects, yes — new residential construction, including ADUs, is generally required to provide for… Read more What is GFCI protection and where is it required in an ADU? GFCI — ground-fault circuit interrupter — protection is a fast-acting device that monitors the current going out on the hot… Read more What is AFCI protection and where is it required? AFCI — arc-fault circuit interrupter — protection is a device that detects the unique electrical signature of a dangerous arc (from… Read more Does an ADU need its own separate electrical meter? Usually no — most California ADUs are powered by a subpanel fed from the existing main house panel and share the main meter, which… Read more How is solar handled on electrical plans for an ADU? Solar shows up on ADU electrical plans in one of three ways: a full solar PV system, solar-ready conduit and panel provisions, or —… Read more What are the most common reasons electrical plans for ADUs get plan check corrections? Most ADU electrical corrections come down to a handful of recurring issues — and nearly all of them are avoidable with a complete,… Read more What electrical work is specific to garage conversions vs. new detached ADUs? The code requirements for the finished dwelling are the same — both need a properly sized panel, GFCI/AFCI protection, dedicated… Read more What is battery storage readiness (ESS-ready) and which ADUs need it? Battery storage readiness — often called ESS-ready (Energy Storage System ready) — means the electrical design includes the panel… Read more

ADU Plumbing Plans

Water supply, drainage, sewer, gas, and fixture layouts designed to code, from $995.

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What is included in the plumbing plans for an ADU? Our ADU plumbing plans are a permit-ready drawing set that documents every part of your unit's water, waste, venting, and (where… Read more How does sewer connection work for a detached ADU? Getting a detached ADU's waste to the public sewer comes down to one of three approaches — a tie-in to your existing lateral, a… Read more Does a detached ADU need its own water meter? Usually no — most California ADUs, including detached units, share the existing water meter and service with the main house, and… Read more What type of water heater is recommended for a California ADU? For most new California ADUs the recommended choice is a heat-pump water heater, because it is highly efficient and aligns with the… Read more What does CALGreen require for plumbing fixtures? CALGreen (the California Green Building Standards Code, Title 24 Part 11) sets mandatory maximum flow rates for every new… Read more What is the DWV system and why must it be shown on plans? The drain-waste-vent (DWV) system is the network of pipes that carries wastewater away from every fixture while keeping the drain… Read more What is backflow prevention and why is it required? Backflow prevention is the set of devices and design practices that stop used or contaminated water from flowing backward into the… Read more What are the unique plumbing challenges in a garage conversion? The defining plumbing challenge in a garage conversion is that the fixtures sit on a concrete slab that has no plumbing under it —… Read more What is a fixture unit count and why does it matter? A fixture unit is a standardized number the plumbing code assigns to each fixture to represent its load on the system — water… Read more What is the minimum plumbing required for an ADU to qualify as a legal dwelling? To qualify as a legal Accessory Dwelling Unit, California Government Code requires that the unit provide complete independent… Read more What are the most expensive plumbing surprises on ADU projects? The plumbing line items that blow up ADU budgets are almost always the ones hidden underground or buried in a utility fee schedule. Read more

Garage Conversion MEP Plans

Full Mechanical, Electrical & Plumbing drawings to convert a garage into a permitted ADU.

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Why does a garage conversion need full MEP plans if the garage already has electricity? Because the electricity a garage already has was designed for non-habitable, non-residential use — and that is not the same thing… Read more What are the most expensive MEP aspects of converting a garage to an ADU? The two costliest MEP variables in a garage conversion are almost always the plumbing — because a complete drain-waste-vent system… Read more What happens to the garage door when it is converted to an ADU? In nearly every garage-to-ADU conversion, the garage door is removed and the opening is framed into a finished, insulated exterior… Read more Do garage conversions need Title 24 compliance in California? Yes — garage conversions require Title 24 energy compliance documentation, but under alteration rules rather than new-construction… Read more Does a garage conversion require a fire separation between the ADU and the main house? Often, yes — but it depends on the configuration. Read more What permits are required for a garage conversion in California? A California garage conversion is permitted as the creation of a legal dwelling, so it requires a building permit and the… Read more How long does it take to permit a garage conversion in California? For a complete, well-coordinated application, California garage conversions generally move through permitting in a matter of weeks… Read more What inspections are required during a garage conversion? A garage conversion is inspected at the same key construction milestones as any ADU, with a few conversion-specific checks built in… Read more How much does MEP planning and engineering cost for a garage conversion vs. a new detached ADU? For MEP plans, a garage conversion costs essentially the same as a new detached ADU — the same flat pricing, scaled by square… Read more What common garage conversion MEP mistakes delay permits? Most garage-conversion permit delays come from a handful of avoidable MEP and energy-code oversights — incomplete electrical… Read more

Title 24 Energy Reports

California energy-compliance reports (registered CF1R) — add to any plan set for $240.

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What is a Title 24 report and what documents does it include? A Title 24 report is the energy-compliance package that proves your ADU's design meets California's Building Energy Efficiency… Read more Is a Title 24 report required for every ADU type in California? In almost every case, yes — if you are building a new ADU or converting existing space into a dwelling, California's energy code… Read more What California climate zone is my ADU in and why does it matter? Your ADU's climate zone is determined by its project address — California is divided into 16 climate zones, and your jurisdiction's… Read more What is HERS testing and when is it required? HERS testing is independent, third-party field verification of certain energy measures by a certified HERS (Home Energy Rating… Read more What changed with the 2025 California Title 24 energy code for ADUs? California revises its Building Energy Efficiency Standards on a three-year cycle, and the 2025 code took effect for permit… Read more What is the solar PV requirement for ADUs in California? It depends on the project. Read more What is the difference between prescriptive and performance compliance? Both are valid ways to prove your ADU meets Title 24, recorded in the same registered CF1R. Read more Why bundle Title 24 with MEP plans? Because the Title 24 report and your MEP plans are tightly interdependent, bundling them prevents the mismatches that are the… Read more What are the most common Title 24 mistakes causing plan check rejections? Most Title 24 rejections come down to a handful of avoidable issues: the equipment on the plans doesn't match the report, the… Read more Do I need Title 24 for a garage conversion that doesn't add new floor area? Yes — in almost all cases. Read more

Permit-Ready ADU MEP Services

Residential MEP Plans — Single-Family Homes

Full MEP Package — Mechanical, Electrical & Plumbing

ADU Mechanical (HVAC) Plans

ADU Electrical Plans

ADU Plumbing Plans

Garage Conversion MEP Plans

Title 24 Energy Reports

Why Choose ADU MEP Plans?

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