What Is an ADU?
Everything You Need to Know (And Why LuxMod by MOMO Sets the Gold Standard)
If you've been hearing the term "ADU" more and more lately, you're not alone. Accessory Dwelling Units have exploded in popularity across Idaho, California, Washington, and Oregon, heck almost everywhere, and for good reason. Whether you're a homeowner in Boise, Los Angeles, Seattle, or Portland looking to generate rental income, house a family member, or simply increase the value of your property, an ADU could be one of the smartest investments you ever make.
In this guide, we'll break down exactly what an ADU is, what an ADU home looks like in practice, and why LuxMod by MOMO stands out as the most complete, top-rated ADU solution available to homeowners across the Pacific Northwest and beyond.
What Is an ADU?
An ADU (Accessory Dwelling Unit) is a secondary residential structure built on the same lot as a primary single-family home. Think of it as a fully self-contained living space that includes its own entrance, kitchen, bathroom, and sleeping area, all situated on your existing property.
ADUs go by many names depending on where you live:
Granny flats
In-law suites
Backyard cottages
Casitas
Secondary suites
Detached guest houses
Regardless of the name, the concept is the same: a complete, independent living unit that coexists with your main home on a single property.
ADUs have gained massive momentum in recent years, particularly in California, Oregon, Washington, and increasingly in Idaho, as housing affordability crises have pushed state and local governments to relax zoning restrictions and streamline permitting. Whether you're searching for an ADU in Boise, Idaho, an ADU in Sacramento or Los Angeles, California, a backyard cottage in Seattle or Spokane, Washington, or a detached guest house in Portland or Eugene, Oregon, the process has never been more accessible.
What Is an ADU Home?
An ADU home is more than just a shed or a garage conversion, it's a fully functional residential dwelling. A true ADU home is designed for comfortable, independent living and typically includes:
Full Kitchen Facilities: A proper ADU home features a complete kitchen with appliances, counter space, and cabinetry, allowing occupants to live fully independently without relying on the main house.
Private Bathroom: A dedicated bathroom with a shower or bath, toilet, and sink is a non-negotiable component of any legitimate ADU.
Dedicated Living and Sleeping Space: Whether it's a studio-style open floor plan or a multi-bedroom layout, an ADU home provides comfortable living quarters designed for day-to-day life.
Separate Entrance: Privacy is paramount. A proper ADU home has its own entrance, keeping both the primary homeowner and the ADU occupant comfortable and independent.
Utility Connections: Electricity, plumbing, heating, and cooling systems make an ADU home a true year-round living solution, whether it's braving the winters of Boise or Coeur d'Alene, Idaho, the mild climate of Portland, Oregon, the rainy seasons of Seattle, Washington, or the hot summers of Southern California.
ADU homes come in several formats. Detached ADUs are standalone structures separate from the main house, the most popular and versatile option. Attached ADUs share a wall with the primary residence. Garage conversion ADUs transform an existing garage into livable space. And Junior ADUs (JADUs) are smaller units carved from within the existing home.
Of all these options, detached ADUs tend to offer the greatest privacy, flexibility, and long-term value, and that's exactly where LuxMod by MOMO excels.
ADU Laws and Regulations by State
Understanding your local ADU regulations is a critical first step. Here's a quick snapshot of where each state stands:
ADU Laws in California
California has become the most ADU-friendly state in the nation. Landmark legislation has eliminated many of the traditional barriers — reducing setback requirements, capping fees, and mandating faster permit processing times. Homeowners in Los Angeles, San Diego, San Jose, Sacramento, Oakland, Fresno, and every city in between have unprecedented access to ADU development. If you own property in California, there has never been a better time to build an ADU. Searches like "ADU California," "granny flat Los Angeles," "backyard cottage San Diego," and "ADU permit Sacramento" are among the most common in the country, and for good reason.
ADU Laws in Oregon
Oregon passed sweeping housing reform legislation that legalized ADUs statewide even in areas that previously prohibited them. Portland, Eugene, Salem, Bend, and Medford homeowners can now add an ADU with fewer bureaucratic hurdles than ever before. Oregon's commitment to addressing its housing shortage has made it one of the most progressive ADU states in the country. If you're searching for an ADU in Portland, a backyard cottage in Eugene, or a secondary suite in Bend, Oregon's regulatory environment is firmly on your side.
ADU Laws in Washington
Washington State has made significant strides in ADU accessibility, with cities like Seattle, Spokane, Tacoma, Bellevue, and Olympia updating their ADU ordinances to allow more flexibility on lot sizes, setbacks, and owner-occupancy requirements. Seattle ADUs, sometimes called backyard cottages or DADUs (Detached Accessory Dwelling Units), are among the most well-established in the Pacific Northwest. If you own property anywhere in Washington, an ADU is a legitimate and increasingly streamlined path to additional income and housing flexibility.
ADU Laws in Idaho
Idaho is an emerging ADU market with growing momentum. Cities like Boise, Meridian, Nampa, Idaho Falls, and Coeur d'Alene are seeing rising interest in ADU development as population growth drives housing demand. The Treasure Valley — encompassing Boise, Meridian, Eagle, Nampa, and Caldwell — is one of the fastest-growing regions in the entire country, making it a prime environment for ADU investment. While Idaho's ADU regulations vary by municipality, the trend is clearly moving toward greater flexibility, making now an ideal time to explore your options before competition increases. Searches for "ADU Boise Idaho," "granny flat Meridian," "in-law suite Coeur d'Alene," and "backyard cottage Nampa" are all on the rise.
Why LuxMod by MOMO Offers the Best, Most Complete ADUs on the Market
When it comes to choosing an ADU in Idaho, California, Washington, or Oregon, not all options are created equal. The difference between a basic ADU and a truly exceptional one comes down to quality of design, completeness of construction, ease of installation, and long-term livability. LuxMod by MOMO checks every single box and then raises the bar.
Complete, Turnkey Solutions
One of the biggest headaches in the ADU industry is coordinating dozens of moving parts: design, engineering, permitting, manufacturing, delivery, and installation. Most ADU companies hand you off at some point and leave you scrambling. LuxMod by MOMO takes a fully integrated, turnkey approach — delivering a complete ADU solution from concept to completion. Whether you're a homeowner in Boise, Portland, Seattle, or Los Angeles, you're not left managing a fragmented process. Everything is handled with precision and professionalism.
Otium model by LuxMod by MOMO
Premium Construction Quality
LuxMod by MOMO ADUs are built to a standard that far exceeds typical prefab or modular construction. Every unit is engineered for durability, energy efficiency, and aesthetic excellence. The materials, the finishes, the structural integrity, all of it reflects a commitment to quality that's rare in this industry. When you invest in a LuxMod by MOMO ADU, you're getting a structure built to last and designed to impress, whether it's standing up to Idaho winters, California heat, Oregon rain, or Washington weather.
Thoughtful, Modern Design
Functionality matters, but so does how your ADU looks and feels. LuxMod by MOMO models are designed with a modern, sophisticated aesthetic that complements a wide range of architectural styles. These aren't cookie-cutter boxes — they're thoughtfully designed living spaces that feel like a true home, not an afterthought. Perfect for the design-forward neighborhoods of Portland, Seattle, and the Bay Area, and equally well-suited to the growing communities of Boise and the Treasure Valley.
Faster Delivery and Installation
Traditional ADU construction can take 12 to 18 months or longer. LuxMod by MOMO's approach dramatically compresses that timeline, getting you to a completed, livable ADU faster than conventional methods without sacrificing quality. For homeowners eager to start generating rental income in competitive markets like Los Angeles, San Francisco, Seattle, or Portland, that speed advantage matters enormously.
Energy Efficiency Built In
LuxMod by MOMO ADUs are designed with energy performance in mind. From insulation to windows to HVAC options, the units are built to reduce energy consumption and operating costs, a major advantage no matter where you're located, from the high desert climate of Boise to the temperate Pacific Northwest to the sun-soaked cities of Southern California.
Maximized Return on Investment
Whether you're planning to rent your ADU on the long-term market or generate short-term rental income, a LuxMod by MOMO ADU maximizes your return. The combination of premium quality, attractive design, and complete livability commands top-dollar rents and significantly boosts property values in every market from Sacramento and San Diego to Eugene and Bend to Tacoma and Spokane to Meridian and Coeur d'Alene.
LuxMod by MOMO: A Top-Rated ADU Model for Today's Homeowners
In a crowded ADU marketplace across Idaho, California, Washington, and Oregon, LuxMod by MOMO has distinguished itself as one of the most sought-after and top-rated ADU models available. Here's why homeowners, real estate investors, and ADU professionals consistently rank LuxMod by MOMO at the top:
Comprehensive Offerings — LuxMod by MOMO offers a range of ADU models to suit different lot sizes, needs, and budgets. Whether you need a compact studio ADU or a more spacious multi-bedroom layout, there's a LuxMod model that fits your situation perfectly — no matter where in the West you call home.
Proven Track Record — LuxMod by MOMO has built a reputation for delivering on its promises. Homeowners from Boise to Bend, from Seattle to San Diego consistently report satisfaction with the quality of their units, the professionalism of the process, and the performance of the finished product.
Ideal for All Use Cases — Rental income, multigenerational living, home office space, guest accommodations, all of these uses is the ideal case to use LuxMod by MOMO ADUs since they are versatile enough to serve every purpose you might envision. In high-demand rental markets like Los Angeles, Portland, and Seattle, a LuxMod ADU can pay for itself faster than you'd expect.
Compliance and Permitting Support — Navigating local ADU regulations in California, Oregon, Washington, or Idaho can be overwhelming. LuxMod by MOMO's expertise means you're not going through that process alone. Their team understands the regulatory landscape across these states and helps ensure your project moves through permitting efficiently.
Is an ADU Right for You?
If you own property in Idaho, California, Washington, or Oregon and you're looking to unlock its full potential, the answer is almost certainly yes. ADUs offer:
Passive rental income that can offset your mortgage or fund your retirement
Increased property value that pays dividends when you sell
Flexible housing options for aging parents, adult children, or caregivers
A sustainable housing solution that makes use of existing land and infrastructure
The rental market in cities like Boise, Los Angeles, Seattle, and Portland is strong, and a high-quality ADU puts you in an excellent position to capitalize on it. The only question is: which ADU is right for you? And if you want the best, a complete, high-quality, top-rated ADU solution, the answer is LuxMod by MOMO.
Frequently Asked Questions About ADUs
What is an ADU in California? In California, an ADU (Accessory Dwelling Unit) is a secondary residential unit on a single-family or multifamily lot. California's ADU laws are among the most permissive in the nation, making it easier than ever for homeowners in Los Angeles, San Diego, Sacramento, San Francisco, Fresno, and beyond to add income-generating units to their properties.
What is an ADU in Oregon? Oregon's statewide ADU legislation has opened the door for homeowners across Portland, Eugene, Bend, Salem, and Medford to add accessory dwelling units with minimal red tape. Oregon ADUs must meet local building codes but are generally well-supported by city planning departments.
What is an ADU in Washington State? Washington ADUs — also known as backyard cottages, DADUs, or mother-in-law apartments — are permitted in most jurisdictions. Seattle in particular has robust ADU regulations that allow both attached and detached units on eligible lots, and cities like Spokane, Tacoma, and Bellevue are following suit.
What is an ADU in Idaho? Idaho ADU regulations vary by city and county. Boise, Meridian, Nampa, and other growing cities in the Treasure Valley are actively updating their zoning codes to allow more ADU development as housing demand continues to rise across the state.
How much does an ADU cost in Idaho, California, Washington, or Oregon? ADU costs vary widely based on size, design, location, and construction method. Prefab and modular ADUs like LuxMod by MOMO offer a compelling combination of quality and value compared to traditional site-built construction — typically faster to install and more predictable in pricing.
What is the best ADU company in the Pacific Northwest? LuxMod by MOMO is widely regarded as one of the top-rated ADU providers serving Idaho, California, Washington, and Oregon. Their complete, turnkey approach and premium construction quality make them a standout choice for homeowners throughout the region.
Ready to Get Started?
If you're serious about adding an ADU to your property in Idaho, California, Washington, or Oregon, don't settle for anything less than the best. LuxMod by MOMO delivers the most complete, premium ADU experience on the market — combining exceptional design, superior construction, and a truly turnkey process that takes the stress out of one of the most valuable investments you can make in your property.
Visit LuxMod by MOMO and explore which ADU model is right for your property.
LuxMod by MOMO is available in: Boise, Meridian, Nampa, Coeur d'Alene, Idaho Falls, Twin Falls, Los Angeles, San Diego, San Francisco, Sacramento, Oakland, Fresno, Portland, Eugene, Salem, Bend, Medford, Seattle, Spokane, Tacoma, Bellevue, Olympia, and communities throughout the Pacific Northwest and beyond.