AGrannio

ADU Guides

Everything you need to plan an ADU — real costs, state rules, financing and the trade-offs between unit types.

How Much Does an ADU Cost in 2026? Real Numbers by Type and State

What an ADU actually costs in 2026 — by construction type (detached, garage conversion, JADU, prefab) and by region, plus the hidden soft costs people forget.

7 min read

Garage to ADU Conversion Cost: What You'll Actually Pay

Converting a garage is the cheapest way to add an ADU. Here's what a garage-to-ADU conversion really costs in 2026, what drives the price up, and when it beats a detached build.

6 min read

California ADU Rules in 2026: Size, Setbacks & Parking

A plain-English guide to California's statewide ADU law in 2026 — the 800 sq ft guarantee, 4 ft setbacks, the transit parking exemption and the 60-day approval rule.

8 min read

ADU vs JADU: Which Backyard Unit Should You Build?

ADU vs JADU explained — the size limits, cost difference, owner-occupancy rules and rental potential of a junior ADU versus a full accessory dwelling unit.

5 min read

How to Finance an ADU: 6 Ways to Pay for a Backyard Home

Six ways to finance an ADU in 2026 — HELOC, cash-out refinance, renovation loans, construction loans, ADU-specific loans and contractor financing — with the pros and cons of each.

7 min read

Prefab ADU Cost: Is a Modular Backyard Home Actually Cheaper?

What a prefab or modular ADU costs in 2026, how it compares to a site-built unit, and the site-work and delivery costs people forget to budget for.

6 min read

The ADU Permit Process: A Step-by-Step Guide for 2026

How the ADU permit process actually works in 2026 — from feasibility and design through plan check, approval and inspections — and how long each stage takes.

7 min read

ADU Rental Income & ROI: Do Backyard Units Actually Pay Off?

How much rental income an ADU generates, how to estimate payback period and ROI, and the factors that make a backyard unit a strong or weak investment.

6 min read

How Long Does It Take to Build an ADU?

A realistic ADU timeline for 2026 — from feasibility and design through permitting and construction — and how prefab and garage conversions can cut months off the schedule.

5 min read

Washington ADU Law (HB 1337): What Homeowners Need to Know

Washington's HB 1337 (2023) requires cities to allow two ADUs per lot. Here's what the law guarantees on size, parking and owner-occupancy — and what it means for your build.

6 min read

Washington State ADU Rules: What Homeowners Can Build in 2026

Washington's 2023 ADU law (HB 1337) requires cities statewide to allow ADUs on single-family lots. Here's what the law mandates and what you can actually build.

5 min read

Oregon ADU Laws: Statewide Rules That Override Local Restrictions

Oregon's SB 1051 (2017) and HB 2001 (2019) make it one of the most ADU-friendly states. Here's what you can build, how large it can be, and what cities can no longer restrict.

5 min read

ADU Regulations in Texas: A City-by-City Breakdown

Texas has no statewide ADU legislation, so the rules depend entirely on your city. Here is the ADU landscape in Austin, Houston, Dallas, San Antonio and other Texas markets.

5 min read

ADU Setback Requirements: How Close to the Property Line?

ADU setbacks determine how close to the property line your unit can sit. California mandates a maximum 4-foot setback for most ADUs. Here is how other states and cities compare.

4 min read

ADU Size Limits by State: Maximum Square Footage Rules Explained

State ADU laws set a floor for maximum allowed ADU size. California allows up to 1,200 sq ft; Oregon up to 900 sq ft on smaller lots. Here are the rules by state.

5 min read

Container Home ADU: Is a Shipping Container ADU Cheaper or Legal?

Shipping container ADUs look striking — but are they actually cheaper to build, and are they legal in your jurisdiction? An honest look at the trade-offs.

5 min read

ADU Building Codes: Key Requirements for Safety and Permitting

ADUs must meet the same building codes as primary homes — electrical, plumbing, structural, fire and energy. Here are the key requirements to plan around.

5 min read

ADU Rules in Florida: What Homeowners Need to Know in 2026

Florida has no statewide ADU mandate — rules are set by your city or county. Here's how Florida ADU zoning works and what to check before you build.

5 min read

ADU Parking Requirements: Are You Required to Add a Parking Space?

California dropped ADU parking requirements near transit, and many states followed. Here's how ADU parking rules work and how they affect your project's feasibility.

4 min read

ADU Impact Fees: What They Are and How to Reduce Them

Impact fees are one-time charges on new construction. California exempts most ADUs under 750 sq ft. Here's how impact fees work for ADUs and how to reduce them.

5 min read

Building an ADU for Aging Parents: The Complete Planning Guide

An ADU lets aging parents live nearby while maintaining independence. This guide covers planning for accessibility, permitting, cost and financing a family ADU project.

6 min read

ADU Zoning Laws: How Zoning Affects What You Can Build on Your Lot

ADU zoning rules control where, how large and how dense ADUs can be on a given parcel. Understanding your zoning designation is the first step in any ADU project.

5 min read