Seabrook Island is 372 homes with a $530,394 median market value and a top of the range at $1.31 million. A 3.2 times spread inside one subdivision is not a market you can price off a median, and that is the single most important thing to understand before you list or buy here. In a neighborhood this small, every sale sets a comp that gets quoted back to you for a year and a half. Luxury marketing in Seabrook Island is not about a glossier flyer. It is about defending a number that the public record does not yet support.
Why the tax roll is the wrong starting point for a Seabrook Island price
Here is the gap that decides most listings in this neighborhood. The median appraised value works out to $140.75 per square foot. Homes are actually selling at $171.36 per square foot. Buyers are paying roughly 21.7 percent above what the appraisal district carries, which means any pricing conversation anchored to a tax statement starts about a fifth of the way underwater.
| Pricing input | Seabrook Island figure | What it tells you |
|---|---|---|
| Median appraised price per sq ft | $140.75 | What the appraisal roll currently carries |
| Median sold price per sq ft | $171.36 | What buyers are actually paying |
| Gap | About 21.7% above roll | The roll lags the market here |
| Median market value | $530,394 | The middle, not the target |
| Price range | $408K to $1.31M | Pricing is per property, not per median |
| Active listings | 8 | Thin supply, so each comp carries weight |
| Recent sales | 83 | Enough depth to build a defensible case |
The working rule is that in a 372-home neighborhood you do not price from averages, you price from the four or five genuinely comparable closings and then argue the differences in writing. That written case is what survives an appraisal review, and in a market selling 21 percent above the tax roll, the appraisal review is the part of the transaction most likely to kill your number.
Seabrook Island by the numbers
| Measure | Seabrook Island (Seabrook 77586) |
|---|---|
| Single-family homes | 372 |
| Median square footage | 3,514 |
| Median lot size | 10,560 sq ft |
| Median year built | 2003 |
| Median appraised value | $494,611 |
| Median market value | $530,394 |
| Median sold price per sq ft | $171.36 |
| Price range | $408K to $1.31M |
| Active listings | 8 |
| Recently sold | 83 |
| Average beds and baths | 4.02 / 3.81 |
| School district | Clear Creek ISD |
| County | Harris |
A 3,514-square-foot median on a 10,560-square-foot lot tells you what this neighborhood is: substantial houses on suburban lots, built mostly in the early 2000s, rather than estate parcels. That shapes the buyer. The person paying above the roll here is usually trading up within the Clear Lake and Bay Area employment corridor, not arriving from out of state, and that buyer already knows the comps. Figures reflect current public subdivision records and shift with the market.
Eight active listings is the number that should change how you market a house here. With that little supply, your listing is not competing against forty others, it is competing against the memory of the last three closings and against inventory in Clear Lake Forest, Lake Cove and the Kemah waterfront a few minutes south. That makes reach matter in a specific way: the buyer for a $900,000 Seabrook Island house is often already in the area, working at NASA Johnson Space Center, the Bayport industrial corridor or a Clear Lake employer, and is comparing you to a neighborhood rather than to a list. Marketing that only casts a wide net misses them. Marketing that speaks to what Seabrook Island offers that Clear Lake Forest does not is what actually moves the needle.
The factors that actually move a Seabrook Island sale
| Factor | Why it decides price, not just marketing |
|---|---|
| Harris County, not Galveston County | Different appraisal district, different taxing units, different protest calendar than the Galveston County mainland |
| Windstorm coverage and WPI-8 | Coastal construction certification is a per-property question that affects insurability and buyer financing |
| Flood zone and elevation per lot | Position matters lot by lot in this corridor, so pull the current map and any elevation certificate |
| Water access and frontage | Confirm per parcel rather than per neighborhood, since access varies within the subdivision |
| MUD 373 obligation | A utility district line most buyers do not price in until closing |
| Hwy 146 corridor position | Access and noise exposure differ noticeably by street |
| 2003-era systems | Roofs, HVAC and water heaters from that vintage are now at or past replacement age |
Pull the windstorm documentation before you go to market, not after you are under contract. In coastal Harris County, a missing WPI-8 certificate on post-construction work is one of the quietest ways a $900,000 contract falls apart in week three, and it is entirely preventable with a phone call made early.
The tax stack, line by line
| Taxing entity | Rate |
|---|---|
| Clear Creek ISD | 0.9690% |
| City of Seabrook | 0.4552% |
| Harris County | 0.3853% |
| Harris County MUD 373 | 0.1800% |
| Harris County Hospital District | 0.1635% |
| Harris County Flood Control District | 0.0490% |
| Port of Houston Authority | 0.0062% |
| Harris County Department of Education | 0.0048% |
| Combined | about 2.2130% |
On the $530,394 median that is roughly $11,738 a year before any homestead exemption, and MUD 373 alone accounts for about $955 of it. At the $1.31 million top of this range the same stack runs close to $29,000. Buyers in that tier are financing the tax bill as much as the house, so a listing agent who can present the entity list cleanly removes a very common objection before it is raised. Confirm the entity list for the specific address, since configurations vary.
Tradeoffs worth naming
| Option | Upside | Trade-Off |
|---|---|---|
| Seabrook Island, Seabrook | Large early-2000s homes, Clear Creek ISD, thin active inventory that favors a well-marketed listing, and quick access to Kemah, Clear Lake and NASA Johnson Space Center | A 2.2130% combined rate including a MUD, coastal insurance diligence, and a tax roll so far behind the market that pricing requires real work |
| Galveston County mainland luxury | A different appraisal district, often a lower combined rate, and a larger pool of comparable homes | Longer drives to Clear Lake employers and a different windstorm and coastal insurance picture |
| Clear Lake waterfront with direct boat access | Frontage and moorage you cannot replicate inland at any price | Materially higher entry cost, bulkhead and dock maintenance, and a narrower resale buyer pool |
None of these is better in the abstract. The right one depends on whether you are buying for the commute, the water or the resale, and those three answers rarely point at the same street.
Why Client for Life, not "best agent"
Mandie McMillan has 26 years in this business and 50 years in this area. She was born and raised in La Marque, the center of Galveston County, and has lived in her League City home for the last 18 years. On the luxury side she holds the CLHS Certified Luxury Home Specialist designation alongside SRS, and she is a RE/MAX International Hall of Fame inductee and a repeat RE/MAX Chairman's Club and Platinum Club honoree. She served as 2017 President of the Bay Area chapter of the Women's Council of Realtors and as 2018 Texas District Vice President, and the team is ranked among the Top 250 RE/MAX teams in Texas.
In 2025 The Mandie McMillan Team closed 75 sides and $22,127,458 in volume with six producing agents, and Mandie personally closed 30 sides and $11,676,748. Roughly 12.5 sides and $3.7M per agent is depth, not headcount, and in a 372-home neighborhood where one bad comp sets the tone for eighteen months, depth is the thing you are actually hiring.
If you are buying or selling in Seabrook Island, call The Mandie McMillan Team at RE/MAX Coastal. We will build the written comp case, pull the windstorm and flood documentation, and price your house against what buyers are paying rather than what the roll says.
