SH 146 and Windstorm Rules: Why Seabrook Is In, Nassau Bay Isn't

A highway number that decides more than your commute

Most people think of State Highway 146 as the road that gets them to the boardwalk in Kemah or the refineries past Pasadena. On the Clear Lake side, it also happens to be the dividing line Texas uses to decide which Harris County homes are eligible for windstorm coverage through the Texas Windstorm Insurance Association, and which ones are on their own. That is not a small distinction if a hailstorm or straight-line wind event ever takes a serious bite out of your roof.

Here is the short version. Galveston County is first-tier territory for TWIA across the board — League City, Dickinson, Kemah, Clear Lake Shores, Bacliff, San Leon, and Santa Fe all qualify, along with the part of Friendswood south of Clear Creek. Harris County is a different story. TWIA's own language limits Harris County eligibility to "parts of Harris County east of Highway 146," and TDI's published list narrows that further to five specific communities: La Porte, Morgan's Point, Pasadena, Seabrook, and Shoreacres.

Why Seabrook makes the list and Nassau Bay doesn't

Seabrook sits mostly east of SH 146, which is why it shows up by name on TDI's windstorm map even though it's a Harris County address. Nassau Bay, El Lago, Taylor Lake Village, Webster, and Clear Lake City all sit west of that line. Same county, same flood risk from the lake, same hurricane exposure off Galveston Bay — but none of them are eligible for TWIA, and the WPI-8 inspection process that goes with it simply doesn't apply there. It's a strange-looking rule until you remember it was drawn around a highway corridor, not a flood zone or a wind-speed map.

There's a wrinkle even within Seabrook. The city's boundary doesn't track the highway perfectly, so a handful of Seabrook addresses actually fall on the west side of 146. If that's your street, TDI's own guidance is to call and confirm rather than assume — their windstorm line is 800-248-6032, and it's a five-minute call that settles the question for good.

How to check which side of the line your address is on

You don't have to guess, and you shouldn't rely on which side of the road feels more "east." Here's how to actually confirm it:

1. Pull your property record from the Harris County Appraisal District and note the recorded address and plat.
2. Check your location against TDI's published windstorm eligibility map, which shows the SH 146 boundary for Harris County directly.
3. If you're inside Seabrook, Shoreacres, Morgan's Point, La Porte, or Pasadena but near the highway, call TDI at 800-248-6032 and ask them to confirm eligibility by address, not just by city name.
4. If you're in Nassau Bay, El Lago, Taylor Lake Village, Webster, or Clear Lake City, treat your roof project as outside TWIA territory and plan your project timeline and materials accordingly — there's no WPI-8 inspection to schedule either way.
5. Keep a copy of whatever TDI tells you with your other property records; it's useful to have on hand if you ever sell or refinance.

For homeowners on the Galveston County side of our service area, this same geography is why a roof replacement built to windstorm code looks different on paper than one done a few miles north. The county line, not the quality of the work, is what determines whether a WPI-8 is part of the job.

What this means when you're comparing quotes

If your address is on the TWIA side of the map — Galveston County, or Harris County east of 146 — a contractor quoting a full roof replacement should be able to speak to WPI-8 inspection steps as part of the process, not as an upsell tacked on later. If you're west of the highway, that conversation doesn't apply, and a straightforward quote for materials, flashing, and code-compliant installation is what you're after instead. Either way, a quote that just says "same as before" without naming which rules apply to your specific address is one worth asking more questions about.

We work across this whole patchwork of jurisdictions, from Seabrook to Nassau Bay, and we start every estimate by confirming which side of the map a property sits on before anyone talks about shingles. You can see the full list of communities we cover, Galveston and Harris County alike, on our service area page.

Knowing whether your address falls east or west of SH 146 takes five minutes and changes what rules actually apply to your roof, so it's worth confirming before you need the answer in a hurry.