Contra Costa County New Construction Homes for Sale
By Matthew Martinez, Founder, CEO & Managing Broker, Diamond Real Estate Group. California DRE #01869679.
New homes in Contra Costa County are built inside its cities and inside the county’s Urban Limit Line, which keeps at least 65% of the county’s land in non-urban use. Most new subdivisions are in the East County cities and southern Antioch, with infill and townhome projects closer to BART, and the largest long-range plan is Concord’s reuse of the former Naval Weapons Station. Before you sign with a builder, check every special tax on the lot, read the public report and HOA documents, and know the warranty and claims rules California’s SB 800 gives you.
This page covers plans, rules and costs only, with no prices or market statistics. For the full county picture, start on our Contra Costa County homes page.
At a glance
| Item | What to know | Source |
|---|---|---|
| Urban Limit Line | Renewal measure extends the ULL and 65/35 Land Preservation Plan through December 31, 2051; expanding it by more than 30 acres needs voter approval | CEQAnet: 2026 ULL Renewal |
| Concord Reuse Project | Area Plan adopted 2012 for the former Concord Naval Weapons Station; over 65% planned as parks, trails and open space | Concord Reuse Project: About |
| Antioch: Sand Creek Focus Area | Southern Antioch, south of Sand Creek and east of Deer Valley Road (formerly FUA-1); new subdivision proposals reviewed there | City of Antioch staff report, Feb. 2024 |
| Mello-Roos notice | Builder must give a signed Notice of Special Tax before you sign; 3 or 5 days to cancel | Gov. Code 53341.5 |
| Builder’s minimum warranty | At least one year on fit and finish items | Civil Code 900 |
| Public report | Must be given to you before you sign the sales contract | DRE: New residential housing FAQ |
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Where to look in Contra Costa County
The Urban Limit Line sets the outer edge. The county’s Urban Limit Line is a boundary in the land use element of its 2045 General Plan. On December 9, 2025, the county approved sending a renewal to voters that would extend the line and the 65/35 Land Preservation Plan Ordinance through December 31, 2051, keeping at least 65% of the county’s land in non-urban uses, according to the county’s CEQA filing. It also notes that moving the line out by more than 30 acres requires voter approval. The measure appeared as Measure A on the June 2, 2026 ballot, and early returns reported by Patch showed it passing; confirm the certified result with the county elections office. For a buyer, it means new subdivisions happen mainly inside existing cities and their planned growth areas, not on open land at the edge.
East County: Brentwood, Oakley, Antioch and Pittsburg. These cities hold much of the county’s subdivision-scale building. In southern Antioch, the city calls the area south of Sand Creek and east of Deer Valley Road the Sand Creek Focus Area, formerly Future Urbanizing Area 1. In February 2024 the Planning Commission reviewed a preliminary development plan there for a 160-acre site, a non-binding step before any entitlement. Newer East County neighborhoods often carry assessments and association dues, so read our Brentwood and Antioch association and assessment cost guides; we have the same guide for each East County city. Browse Brentwood real estate, Oakley real estate, Antioch real estate and Pittsburg real estate.
Concord. The Concord Community Reuse Project plans new uses for the Naval Weapons Station, which closed in 2005. Its Area Plan, adopted in 2012, places single-family homes and townhouses next to existing neighborhoods on the south side and clusters housing, offices and retail around the BART station and along Highway 4. The project page says the city began a new master developer search in May 2023 and expected to prepare a specific plan and EIR with that developer; the page was last updated in July 2023, so check the city for current status. Homes there are a long-range prospect, not something to tour this year. See Concord real estate.
San Ramon Valley and central county. In San Ramon and other central cities, new homes are more often infill, townhomes or smaller subdivisions within planned communities. Our San Ramon association and assessment costs guide covers what newer neighborhoods there can carry. If you are looking at a new townhome or condo, read our condo and townhome reserve analysis.
For how the cities compare on transit, water and rules, see where to live in Contra Costa County.
What to check before you buy
1. Every special tax. New subdivisions may sit in one or more community facilities districts (Mello-Roos), plus landscape, lighting or other assessment districts. Under Government Code 53341.5, the subdivider must furnish a signed Notice of Special Tax before you sign a purchase contract or deposit receipt. You can cancel in writing within three days of in-person delivery or five days after mailing. A missing notice does not undo the sale, but a willful violation exposes the subdivider to your actual damages. Our Mello-Roos guide shows how to read the tax bill.
2. The DRE public report. Under Business and Professions Code 11018.2, a builder needs a Subdivision Public Report from the Department of Real Estate before selling lots in a residential subdivision, and the DRE says you must receive it before you sign.
3. HOA documents. Planned communities and townhome projects usually have an association. Get the CC&Rs, budget and reserve study; see our HOA documents guide.
4. Taxes in year one. Expect supplemental tax bills after closing; see our supplemental tax bill guide. The preliminary title report shows recorded special tax notices and easements.
5. Your own inspection. City inspectors check code compliance, not workmanship. Hire a private inspector before drywall if allowed and before the final walk-through; see home inspections in California.
SB 800 warranties and claims
California’s Right to Repair Act (SB 800), Civil Code 895 and following, sets building standards for new homes and a process the owner and builder must follow before a lawsuit.
| Rule | What it says | Statute |
|---|---|---|
| Fit and finish | At least a one-year written limited warranty on cabinets, mirrors, flooring, walls, countertops, paint and trim | Civil Code 900 |
| Documents at sale | Maintenance recommendations, product and builder warranties, the claims agent’s name and address, a recorded notice on title and a copy of the statute | Civil Code 912 |
| Plans and soils reports | Within 30 days of a written request about structural, fire safety or soils provisions | Civil Code 912 |
| Prelitigation notice | Written notice by certified mail, overnight mail or personal delivery; a customer service request does not count | Civil Code 910 |
| Time limit | Generally 10 years after substantial completion | Civil Code 941 |
On hillside and expansive-soil sites, the right to request grading plans and final soils reports is useful. Keep the warranty and claims documents, and the builder must tell you to pass them to your buyer when you sell. A builder warranty is different from a home warranty contract. Read buying new construction in California for the full process.
Your agent at the builder’s office
Model-home sales staff represent the builder. To have your own agent, bring them on your first visit or follow the builder’s registration policy, which varies. Builder contracts differ from the standard resale form, so have your agent review deposit, timing and incentive terms. Our commissions guide explains how buyer-agent pay works today.
Questions people ask
What is the Contra Costa Urban Limit Line?
A boundary in the county general plan that limits urban development to keep at least 65% of the county’s land in non-urban use. The 2026 renewal measure would extend it through 2051, and expanding it by more than 30 acres needs voter approval.
Where are new homes being built in Contra Costa County?
Mostly inside East County cities such as Brentwood, Oakley, Antioch and Pittsburg, plus infill and townhome projects in central county cities. Check each project’s status with the city.
When will homes be built at the Concord Naval Weapons Station?
No timeline is set on the project page. The city started a new master developer search in 2023 and planned a specific plan and EIR; check with Concord for current status.
Do new homes in Contra Costa have Mello-Roos?
Many newer subdivisions carry CFD taxes or other assessments. Get the Notice of Special Tax and read the tax bill’s direct charges.
Can I cancel a contract after getting a Notice of Special Tax?
Yes, in writing, within 3 days of in-person delivery or 5 days after the notice is mailed, under Government Code 53341.5.
How long can I bring a construction defect claim?
SB 800 generally allows claims for up to 10 years after substantial completion, with exceptions. Start with the written notice under Civil Code 910.
Should I bring my own agent to a new-home sales office?
If you want representation, yes, on the first visit. Follow the builder’s registration rules so your agent is recognized.
Sources & notes
- CEQAnet: Contra Costa County 2026 Urban Limit Line Renewal, NOD (approved December 9, 2025).
- Context, news: Patch: Contra Costa voters back growth limits (early returns, June 3, 2026).
- Concord Community Reuse Project: About (last updated July 6, 2023).
- City of Antioch: Planning Commission staff report, Feb. 21, 2024, item 6-2 (Sand Creek Focus Area).
- Gov. Code 53341.5.
- California DRE: New residential housing FAQ.
- Civil Code 900, 910, 912, 941 (text read on california.public.law mirror).
Notes: The certified Measure A result was not verified; confirm it with the Contra Costa County Elections Division. Specific plans in Brentwood, Oakley, Pittsburg and San Ramon, city CFD lists and the Concord project’s current developer status were not verified. The Antioch staff report was a preliminary review, not an approval.
General information, not legal, tax or lending advice. Updated November 2026. Primary sources are linked in this guide.
Related: Contra Costa County homes · Where to live in Contra Costa County · Buying new construction in California · Supplemental tax bills
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