Golden State ADUs is a design-build company specializing in one thing: the accessory dwelling unit (ADU). We serve Pleasant Hill homeowners with architectural design, structural and civil engineering, permitting, and construction handled in-house. We know the City of Pleasant Hill Building Division issues your building permit and conducts your inspections, and that qualifying Class 2 units can reach 1,200 square feet, attached to the main house or standing on their own in the backyard.
We are licensed and bonded (LIS. #1125656), trusted by 100+ happy customers, and every project carries a 10-year structural integrity warranty and a 1-year fit-and-finish warranty. You keep your house and add real value to it.
Start with a free 1-hour project walkthrough. Call (916) 909-2387 or book a consultation.
Our ADU Design, Permitting and Construction Services in Pleasant Hill
Design, engineering, permits, and construction live under one contract with one accountable team. Here is what that covers on a Pleasant Hill property.
Detached ADUs and Backyard Bungalows
Detached ADUs are the most requested build here, and the 800-square-foot line shapes the design. Pleasant Hill exempts units of 800 square feet or less from lot-coverage and floor-area-ratio calculations and treats qualifying detached units at that size as Class 1. The City also publishes free pre-approved plans for a 350-square-foot studio, a 636-square-foot one-bedroom, and a 798-square-foot two-bedroom. Call them granny flats, backyard cottages, or backyard bungalows; we design to those thresholds deliberately, or above them when your lot justifies it.
Garage Conversions, Attached ADUs and Above-Garage Units
If your home already has a garage, that footprint is often the most affordable construction path on an older lot. We convert garages into self-contained living space, build above-garage units, and design attached ADUs that extend the house itself. Attached ADUs and detached units over 800 square feet are Class 2, and Class 2 exterior materials and colors must match the primary residence. Our architects design to that matching rule from the first sketch so it never becomes a correction later.
Custom ADUs, Retirement Units and Outdoor Living
Tailored layouts from studio through three bedrooms, including efficiency-focused tiny homes and retirement ADUs for aging parents on the same lot. Some owners want rental income and long-term tenants. Others want family close without family underfoot. Both get a space planned around the life lived inside it, with patios, pathways, and outdoor living areas drawn into the site plan instead of left over. Interior design bundles are available if you want the finishes curated too.
Permitting and Outside-Agency Coordination, Done for You
Permits, paperwork, compliance, done for you. We prepare a fully compliant drawing set, submit through the PHill Online Permit Service Center, complete the forms, pay fees, and schedule inspections. We also chase the clearances that stall projects: the City identifies Contra Costa County Fire Protection District, Central Contra Costa Sanitary District, and the applicable water district as possible outside-agency participants. Pleasant Hill also requires an estimated annual rent on each ADU or JADU application, which we handle with you at submittal.
Why Pleasant Hill Homeowners Choose Golden State ADUs
The ADU builder you hire should carry the whole project instead of handing pieces to three firms that point at each other. Most builders subcontract design and engineering. We do not. Our in-house arm, Golden State Design & Engineering, produces the architectural, structural, and civil work, and our own crews build it. The benefits of streamlining that coordination are simple: one process, no handoff gap, and dollars spent on finishes instead of rework.
We are licensed and bonded (LIS. #1125656), carry insurance and workers’ compensation, and back every build with a 10-year structural integrity warranty and a 1-year fit-and-finish warranty. With 100+ happy customers and 18 Google reviews, our clients hold us to responsiveness: calls and emails answered quickly, updates sent without being asked.
Plain fact: our office is in the Sacramento area, not Contra Costa County. Pleasant Hill is a Bay Area market we travel to, and we would rather say so. What we bring instead of a local storefront is a permitted-project record and current expertise in Pleasant Hill’s ADU standards.
Get a free estimate for your Pleasant Hill ADU. Let’s connect.
How Your Pleasant Hill ADU Construction Project Works, From Concept to Completion
- 1. Free 1-hour walkthrough. Our professionals walk your parcel, read setbacks, utilities, slope, and access, and tell you what will actually fit.
- 2. Design and engineering. Collaborative design plus a line-item estimate separating design, city fees, outside-agency fees, utility installation, site work, and allowances. No hidden costs.
- 3. Permit submittal and clearances. We submit to the Building Division at 100 Gregory Lane and drive the fire, sanitary, and water approvals to secure your permit. Pleasant Hill posts a 21-calendar-day first review and a seven-calendar-day resubmittal review, and California law requires a decision on a complete application within 60 days.
- 4. Build through final sign-off. Milestone updates, our project manager on site for the detail work, and every inspection scheduled and attended by licensed contractors.
Typical, not guaranteed: 3 to 5 months for design and permit plans, 3 to 4 months for construction. Our ADU construction crews work inside Pleasant Hill’s residential hours, 7:30 a.m. to 7:00 p.m. weekdays and 9:00 a.m. to 6:00 p.m. weekends, so your neighbors are never surprised.
Building an Accessory Dwelling Unit in Pleasant Hill: Lots, Setbacks and Site Conditions
Pleasant Hill, like most California cities, rewards knowing your class before you draw anything. Class 1 covers qualifying conversions and detached units of 800 square feet or less. Class 2 covers attached ADUs and detached units over 800 square feet, up to 1,200. Staying at or under 800 square feet keeps you out of lot-coverage math, and the City’s 2026 handout states no ADU parking is required at that size. Side and rear setbacks are generally four feet, tighter than owners expect. State ADU law applies everywhere, so the same legislation that opened backyards in San Jose applies on your street.
Nearly half of Pleasant Hill’s homes were at least 40 years old in the certified Housing Element, which counts these units toward affordable housing goals; small ADUs represent real capacity on lots that are already built out. Compared to a remodeling job inside existing walls, a new unit depends on what is underground, so our walkthrough checks panel capacity, sewer and water routing, foundation type, and unpermitted work, whether you are in Gregory Gardens, Poet’s Corner, College Park, Sherman Acres, or near Contra Costa Centre. The City’s pre-approved foundation plans assume a flat lot with less than 10 inches of slope and no highly expansive or liquefiable soils, and the General Plan calls for geotechnical review in liquefaction areas and slope-stability assessment above 15%. Our engineers resolve those complexities in design, not at footing inspection.
Frequently Asked Questions
How much does an ADU cost in Pleasant Hill?
There is no fixed price. Costs vary with size, site conditions, materials, finishes, and utility work, and Pleasant Hill’s FY 2026-27 permit and plan-check charges are valuation-based rather than one flat fee. For context only, a City sample permit lists a 744-square-foot detached ADU with a declared valuation of $200,000, which is a construction valuation, not a contract price. The most cost-effective routes are usually staying at or under 800 square feet, reusing a garage footprint, or starting from a free pre-approved plan on a suitable flat lot. Use our cost estimator for a range, then get a line-item estimate at your walkthrough.
How long does Pleasant Hill take to review ADU plans?
21 calendar days for first review and seven for resubmittal. Those are review windows, not total time to an issued permit, since corrections and outside-agency clearances add time. State law requires agencies to act on a complete application within 60 days.
What is the difference between a JADU and an ADU?
A JADU is a smaller unit created within the existing home’s walls, while an ADU can be attached or fully detached. Pleasant Hill sorts qualifying conversions and detached units of 800 square feet or less into Class 1, and larger or attached ones into Class 2. Either way, rentals are limited to terms of 30 days or longer. Confirm your parcel with the Planning Division.
What is one drawback of building an ADU?
It is a six-figure, multi-month commitment with construction on your property. Not every lot suits every design, and some yards will not support one at all. Our feasibility review catches that early, including telling you honestly when the answer is no.
Do you serve Pleasant Hill and nearby Contra Costa communities?
Yes. We design, permit, and build throughout California, serving Pleasant Hill and the surrounding Contra Costa area.
Start Your Pleasant Hill ADU With a Free Walkthrough
One hour on your property gives you more clarity than weeks of searching: a feasibility read, guidance on whether Class 1 or Class 2 fits your goals, a realistic budget framework, and a clear next step. Done right, an ADU can elevate a property and transform how a family uses it, and the difference is evident the first time someone stays the night.
Call (916) 909-2387, email office@gsadus.com, or book a consultation. We are at 1001 Enterprise Way #100, Roseville, CA 95678, and we would be glad to come to you.
