If you build in Cameron County, including Brownsville, Harlingen and San Benito, the house has to be inspected during construction under the Texas Department of Insurance windstorm program and earn a certificate of compliance. Without that certificate, the Texas Windstorm Insurance Association will not insure the home for wind and hail. Hidalgo, Starr and Jim Wells counties sit outside the program’s area.
None of this is a reason to avoid building near the coast. It is a set of steps with a clear order, and the only expensive version is the one where a step gets skipped.
Where does windstorm certification apply?
The Texas Windstorm Insurance Association, TWIA, insures wind and hail along the coast when the private market will not. Its catastrophe area covers the 14 first tier coastal counties plus part of Harris County east of Highway 146, according to TWIA’s fact book. In the Valley, Cameron and Willacy counties are inside it; Hidalgo, Starr and Jim Wells counties are not.
It is not a niche concern in Cameron County. As of March 31, 2026, TWIA carried 11,263 policies and $5.15 billion of insured exposure there.
Why does the certificate matter if I insure with a private company?
Because TWIA stays your fallback only if the house qualifies. State law requires structures in the catastrophe area built or repaired since 1988 to show they meet the applicable building code before TWIA can insure them (Insurance Code section 2210.251), and the proof is TDI’s certificate of compliance.
A private carrier may write your policy today and leave the market tomorrow. With the certificate in hand, you keep TWIA available, and you have a document that coastal buyers and their lenders commonly ask to see when you sell.
Getting certified after the fact is the hard way. Once the walls are closed, the remaining path is an engineer’s evaluation of completed work, and TDI warns that it may cost more. The TDI form that used to cover certain completed work was discontinued in 2020.
How does the inspection process work?
- Apply before construction starts. TDI says state law requires you to apply for a certificate before construction begins. This happens alongside the city or county building permit, not instead of it.
- Inspections during the build. A TDI inspector or a TDI appointed Texas professional engineer inspects the work at key stages, before it gets covered, so connections, fastening and openings can actually be seen.
- The certificate. After the final inspection, TDI issues the certificate of compliance for the structure. Keep it with your closing documents; your insurance agent will ask for it.
Missing an inspection is the classic mistake. If the roof deck is covered before anyone checks the nailing, there is no clean way to prove it afterward.
What changed in 2026?
- A newer code. Effective April 1, 2026, TDI adopted the 2024 International Residential Code and 2024 International Building Code as the minimum construction standards for its windstorm program, replacing the 2018 editions, and added requirements for roof underlayment, according to TDI’s April 2026 bulletin. Your engineer will confirm which edition applies to your project’s dates.
- Flat TWIA rates. TWIA filed no rate change for 2026 policies, and in August 2026 its board voted to file no change for 2027, AM Best reported. The average residential TWIA premium was $2,877.
- New funding rules. 2025 legislation, House Bill 3689, rebuilt how TWIA funds catastrophe losses, replacing public securities with lower interest state financing. A companion bill, House Bill 2518, ended third party premium financing for TWIA policies. If your policy is paid through mortgage escrow, that change does not affect you.
What does it change in the house?
The structure is designed and fastened for the wind speed required at its location, which TDI determines structure by structure. In practice that shows up in the continuous load path from roof to wall to foundation, the nailing of the roof deck, the roof covering and underlayment, and the ratings of windows, exterior doors and garage doors.
Closer to the Gulf, salt air also shortens the life of fasteners, hardware and exterior metal, so the exterior specification changes in Cameron County even where the code would not force it. Our Cameron County page explains how we budget for both.
Who pays for it, and how does it show up in the price?
Two separate lines, both outside the base contract:
| Item | How we handle it |
|---|---|
| Structural detailing the program requires | Built into the Cameron County rate of $120 to $130 per sq ft |
| Windstorm inspections and certification | The one permit not included in our base price; quoted separately |
| Windstorm insurance | Quoted separately, by TWIA or a private carrier |
Engineer inspection fees are set by the engineer, and TDI does not publish a single fee for them, so ask for a quote before construction starts. For the full picture of what the contract covers, see the 2026 cost guide.
On insurance: Texas homeowners premiums rose sharply in 2023 and 2024 and then slowed to a 4.3% average rate change in 2025, the Dallas Fed noted, after TDI data. In September 2026, TDI also encouraged insurers to offer discounts for wind mitigation, including IBHS FORTIFIED roofs, without setting an amount, Fox 26 reported. A new roof built to that standard is worth pricing with your agent.
What should I ask before building in Cameron County?
- Who is the TDI appointed engineer on this job, and what do they charge?
- When will the certificate application be filed, and by whom?
- Which inspections are required, and how will I know each one passed?
- Which wind rated products are specified for the roof, windows, doors and garage door?
- Have I priced insurance, TWIA and private, before closing?
- Where will the certificate be when the house is finished?
Frequently asked questions
Does Hidalgo County require windstorm certification?
No. Hidalgo, Starr and Jim Wells counties are outside the TWIA catastrophe area. Homes there are still built to the wind requirements of the applicable building code; they simply do not go through the TDI windstorm program.
Can a house be certified after it is finished?
Only through an engineer’s evaluation of the completed work, which TDI says may cost more and can be harder to document. Planning the inspections from the start is simpler and cheaper.
Does the certificate lower my insurance premium?
The certificate is about eligibility, not price. Discounts depend on the insurer and on mitigation features such as the roof. Ask your agent which features they credit before your selections are final.
Do barndominiums need windstorm certification in Cameron County?
Yes. The requirement follows the location and the use of the building, not its framing material. Our barndominium builds in Cameron County go through the same program.
Building in Brownsville, Harlingen or San Benito? See our pages for custom home builders in Brownsville, Harlingen and San Benito, or schedule a consultation and we will walk your lot through the windstorm steps before you commit.
