Quartz Construction & Remodeling

Quick Answer: Quartz Construction & Remodeling adds bathrooms to homes throughout Antioch, CA 94509. A half bath (powder room) addition costs $12,000–$28,000; a full bathroom addition runs $28,000–$65,000; a luxury master ensuite costs $60,000–$120,000+. All bathroom additions require plumbing, electrical, and building permits from the City of Antioch. Call (650) 749-7436 for a free estimate.

Bathroom Addition Cost in Antioch, CA — 2025 Pricing

Bathroom Addition Process in Antioch

Antioch homeowners add bathrooms to increase home functionality, accommodate growing families, and add resale value. Quartz Construction manages the full bathroom addition process from permit drawings through final inspection.

• Step 1 — Feasibility assessment: Locate existing drain stack, supply lines, and electrical panel capacity
• Step 2 — Design: Floor plan layout, fixture selection, tile and finishes
• Step 3 — Permit drawings: Plumbing, electrical, and framing plans prepared for Antioch Building Division
• Step 4 — Permit approval: 4–10 weeks for City of Antioch plan review
• Step 5 — Construction: Rough plumbing, rough electrical, framing, waterproofing, tile, fixtures, and finishes
• Step 6 — Inspections and sign-off: Plumbing, electrical, and final building inspections

Where Can I Add a Bathroom in My Antioch Home?

The best locations for bathroom additions in existing homes are spaces close to existing plumbing stacks to minimize pipe run costs. Common options in Antioch homes include:

• Large hallway closet: A 5×8 ft closet can accommodate a full bathroom — the most cost-effective option
• Under-stair space: Can fit a powder room (toilet + sink) with ceiling height tapering
• Bonus room or den conversion: Ideal for creating a new ensuite adjacent to a master bedroom
• Garage or laundry room partial conversion: Shares a plumbing wall, reducing drain rough-in costs
• Room addition (new construction): Full control over size and layout; costs $50,000–$120,000+ for the addition itself

Frequently Asked Questions — Bathroom Addition Antioch

How long does a bathroom addition take in Antioch? A bathroom addition in Antioch takes 3–6 months total: 2–4 weeks for design, 4–10 weeks for permit approval, and 6–10 weeks for construction. Luxury master ensuite additions may take longer due to special-order fixtures and custom tile work.

Does adding a bathroom increase home value in Antioch? Yes — adding a bathroom in the Bay Area typically delivers 60–80% ROI at resale. A home that jumps from 2 to 3 bathrooms in Antioch can command significantly higher prices, as 3/2 homes are the minimum expectation for most buyers in the current market.

Do I need a permit to add a bathroom in Antioch? Yes — adding a bathroom always requires plumbing, electrical, and building permits in Antioch. There are no legal exemptions for bathroom additions since they involve new drain lines, supply connections, venting, and electrical circuits that must be inspected for safety and code compliance.

Get a Free Bathroom Addition Estimate in Antioch

Quartz Construction & Remodeling (CSLB #1003436) specializes in bathroom additions throughout Antioch and the entire Bay Area. From powder rooms to luxury master ensuites, we manage design, permits, and construction under one roof. Call (650) 749-7436 or visit our office at 1570 The Alameda Suite 101, San Jose, CA 95126.

Service area: Antioch, CA 94509 and surrounding Bay Area communities | License: CSLB #1003436 | Phone: (650) 749-7436