Your Complete Guide to Accessory Dwelling Units

Regulations & Permits

ADU zoning laws, permit timelines, and setback rules by state and city — verified against official municipal sources for 2026.

68 articles

Financing

Compare HELOCs, construction loans, cash-out refis, and 203(k) rehab loans for your ADU — with real rates, terms, and qualification tips.

53 articles

Floor Plans

ADU floor plans from 300 to 1,200 sq ft — studio, one-bedroom, and two-bedroom layouts optimized for livability and lot fit.

2 articles

Builder Guide

How to vet ADU contractors, compare bids, manage your build timeline, and avoid the most costly mistakes homeowners make.

54 articles

Design & Interiors

Space-saving ADU design ideas, small-space interior layouts, and aesthetic inspiration for studios through two-bedroom units.

1 article

Featured Guides

Our most popular and comprehensive ADU resources.

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ADU Cost Per Square Foot in 2026: Real Costs by Type & State

See real ADU cost per square foot in 2026 by type, size, and state. Compare detached, attached, garage, and prefab — with worked budget examples.

25 min read

Best Modular ADU Companies 2026: Costs, Code & Scope Matrix

Compare 9 modular ADU companies by code path, service area, and real installed cost — plus a 2026 fit matrix and 20-question vetting checklist.

Regulations & Permits

ADU Fee Waiver Programs 2026: State & City Tracker

ADU fee waiver programs by city: verified permit, impact, SDC & utility fee relief, what's expired, and what to confirm before you pay for plans.

28 min read

1 Bedroom Prefab ADU Costs 2026: 12 Models + Lot Checklist

All-in 1BR prefab ADU costs run $150K–$400K. Compare 12 verified models by price type, scope, and lot fit — plus the lot checklist before you sign anything.

Best 2 Bedroom Prefab ADU 2026: Real Costs, Models & Lot Fit

See the best 2-bedroom prefab ADU models compared by real price, code path, and lot fit — plus the hidden costs that change your total before you quote.

28 min read

Studio Prefab ADU: 2026 Costs, Models & Lot Fit

Studio prefab ADUs run $59K unit-only to $278K+ turnkey. Compare real models by scope, hidden site costs, and lot fit before you pay a deposit.

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Every guide is backed by real project data and current regulations, with sources cited and verification dates on the page. Some links earn us a commission; rankings are never sold, and no partner can pay to change a recommendation.

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Latest Guides

Recently published and updated articles.

Builder GuideEscondido

Best ADU Builders Escondido (2026): Compare & Vet

Compare Escondido ADU builders by project type. PAADU plan status, 2026 costs, CSLB checklist, and a free feasibility check for your lot.

18 min read

Boxabl Casita Review (2026): Unit Price vs All-In ADU Cost

Boxabl Casita lists at $60,000 — that's the unit only. Independent review breaks down the real all-in ADU cost: site prep, foundation, permits, and utilities.

Builder GuideMonterey County

Builder GuideCalifornia

Best ADU Builders Bay Area (2026): How to Choose

No single builder is best for the whole Bay Area. Shortlist by city permit experience, ADU type, and budget — scorecards for SF, Oakland, and San José.

32 min read

Best ADU Builders Monterey County (2026): Permits

How to shortlist the right ADU contractor for Monterey County's coastal vs inland permit paths, covering HCD 2026 updates and coastal checklist rules.

28 min read

Builder GuideSan Luis Obispo

Boxabl vs Abodu: Estimating All-In ADU Cost (2026)

Boxabl vs Abodu isn't a simple price comparison — it's a site, permit, and financing question. Breaks down what each publishes and what's excluded.

32 min read

Best ADU Builders San Luis Obispo (2026): Permits

The best ADU builder in San Luis Obispo knows City vs County rules, 1,200 sq ft max, 4-foot setbacks, and pre-reviewed bid sets — not just construction skill.