Windstorm program
Which Texas Counties Are in the Catastrophe Area
14 counties, plus the part of Harris County east of State Highway 146. Inside that boundary the windstorm program applies. Outside it, none of this does.
The boundary
Fourteen counties and one highway
The designated area is defined by county, with a single exception drawn along a road.
The designated catastrophe area covers Aransas, Brazoria, Calhoun, Cameron, Chambers, Galveston, Jefferson, Kenedy, Kleberg, Matagorda, Nueces, Refugio, San Patricio, and Willacy counties, together with the part of Harris County east of State Highway 146.
That Harris County line is the part people get wrong, and it is the only place in the program where the boundary runs through a populated area rather than along a county line. A property on one side of 146 is inside the program. A property on the other side is not. Nothing about the two buildings has to differ for their obligations to differ completely.
Outside the designated area the windstorm inspection program simply does not apply. There is no certificate to obtain, no WPI-1 to file, and no engineer appointment involved. Wind design requirements still exist in the building code everywhere in Texas, but they are enforced through the ordinary permit rather than through this parallel system.
Why a line exists
The boundary is an insurance instrument
The designation is not a statement about where hurricanes go. It is the boundary of a residual insurance market. Inside it, wind and hail coverage is frequently unavailable in the ordinary market, and the Texas Windstorm Insurance Association exists to write it for property that cannot get it otherwise.
That is why compliance is documented rather than assumed. An association obliged to insure property it did not choose needs a mechanism to know that the property was built to resist the peril it is being insured against. The certificate is that mechanism, which is why it is an eligibility document rather than a code document.
Exposure
Inside the line, position still governs
Being in the designated area is a binary. What the structure has to resist is not.
The boundary decides whether the program applies. It does not decide what the structure must withstand. That comes from the applicable design standard and, critically, from the site's exposure category, which is a property of the ground around the building rather than of the county it sits in.
A house fronting open bay water and a house three miles inland behind mature live oak cover are in different wind environments and can require materially different roof attachment and opening protection, while sitting in the same county, under the same building department, inside the same designated area. Wind design copied from one to the other is a common and expensive error.
This is also why the certificate is not portable between buildings in any sense. It records what was inspected on one structure at one address.
Coverage
Where these counties sit in the state
The designated counties fall across three of the coverage regions this firm is built to serve. Aransas, Calhoun, Kenedy, Kleberg, Nueces, Refugio, and San Patricio are in the Coastal Bend. Brazoria, Chambers, Galveston, Matagorda, and the Harris County strip are in the Greater Houston region. Cameron and Willacy are in the Rio Grande Valley, and Jefferson is on the upper coast.
The regional pages carry the wind, soil, and permitting conditions specific to each, which differ enough along the coast that treating the designated area as one place would be misleading.
Questions
What people ask about this
- Is a property inside the city of Houston in the catastrophe area?
- Only if it lies east of State Highway 146, which is a small part of Harris County and excludes most of the city. The county is not designated as a whole, unlike the other fourteen.
- Does being outside the designated area mean wind design does not matter?
- No. Wind loads are part of the building code everywhere in Texas and are enforced through the ordinary permit and inspection process. What does not exist outside the designated area is the separate windstorm inspection program and its certificate.
Elsewhere in the program
The rest of the windstorm system
Each part of this program is decided by a different party, which is why they are separate pages.
WPI-1 and the inspection sequence
What has to happen before the first nail, and in what order?
Certificates for completed construction
The work is already finished and nobody inspected it. Now what?
The TDI appointment
What is an appointed engineer, and why can't any engineer do this?
The program overview sets out who decides what, and the windstorm capability page covers what this firm is built to deliver once it opens for work.
Start a job
Tell us what the letter is for and we will tell you yes or no
Send the address, what the document is for, and the date it has to be in hand. Some jobs this firm cannot take, and you will hear that in the first conversation rather than after you have paid and waited.