700 sq ft ADU Cost in California (2026)

A 700 sq ft ADU is a versatile size that can fit a spacious one-bedroom or even a compact two-bedroom layout. This makes it a great option for families, long-term rentals, or multi-generational living while keeping construction costs lower than larger units.

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Price Range & Line Items

Here’s how the budget for a 700 SF ADU typically breaks down:

Category	Estimated Cost Range
Construction (hard)	$150,000 – $210,000
Site prep & utilities	$15,000 – $35,000
Design & engineering	$10,000 – $18,000
Permits & city fees	$7,000 – $14,000
Total	$175,000 – $270,000+

Most projects of about 700 square feet fall in the $190k–$230k range, depending on site conditions and finish level.

Construction covers framing, roofing, electrical, plumbing, insulation, and interiors.
Site prep may include grading, foundation work, and trenching for utilities.
Design & engineering provide plans, structural review, and Title 24 energy compliance.
Permits & fees vary by city and often rise with unit size.

💡 Tip: A 700-square-foot ADU can provide nearly the same comfort as a small house, making it attractive both for family use and as a rental.

Project Timeline

Timelines for a 700 sq ft ADU are similar to other mid-size builds. Typical California projects follow this schedule:

Design & permitting (3–4 months): Plans, engineering, energy compliance, and city approvals.
Construction (5–7 months): Site prep, foundation, framing, utilities, and full finishes.
Total duration (8–11 months): From design start to move-in ready.

💡 Ataman Studio coordinates each stage — from drawings and permits to construction support — ensuring efficiency and cost control.

Compare ADU Costs by Size

200 sq ft 300 sq ft 400 sq ft 500 sq ft 600 sq ft 700 sq ft 800 sq ft 900 sq ft 1000 sq ft 1100 sq ft 1200 sq ft

Ready to Build a 700 sq ft ADU?

Get Your Estimate

A 700-square-foot ADU offers the comfort of a small home with the flexibility of custom layouts — from a roomy one-bedroom to a compact two-bedroom. Request your tailored estimate today.