Quadplex with Bay
New
For Sale
$750,000
310 Harbor Light, Port Isabel, TX 78578
Residential Income, Port Isabel, TX
Property Size3,508 SF
Price / SF$213.80
Days on Market3
Property Features for 310 Harbor Light
General Information
Property type
Residential Multi Family
Property subtype
Other
Zoning
MF
Bedrooms
5
Bathrooms
5
Full bathrooms
5
Rooms
Bathroom 5, Bathroom 1, Bathroom 2, Bathroom 3, Bedroom 3, Bedroom 4, Bathroom 4, Bedroom 5, Bedroom 1, Bedroom 2
Parking features
Garage - Attached
Patio and Porch features
Patio
Interior features
Cabinets-Manufactured, Ceiling Fan(s), Furnished, Garage Door Opener, Smoke Detector, Storage, Walk-in Closet, Washer/Dryer Hook-up
Exterior features
Patio, Private Yard, Sprinkler System, Storage
Appliances
Dishwasher, Disposal, Microwave, Refrigerator, Washer/Dryer
Subdivision
Original Townsite Port Isabel
Lot features
Interior Lot
Elementary school district
Point Isabel ISD
Middle school district
Point Isabel ISD
High school district
Point Isabel ISD
Standard status
Active
Size
3,508 SF
Taxes and HOA fees
Tax Year
2026
Tax Annual Amount
7500
Building Details
Year built
1989
Floors in Building
1
Number of units
4
Flooring type
Tile, Carpet
Building materials
Block, Brick
Roof type
Composition, Flat
Additional Structures
Storage
Listing Agency:
Pinkerton Realty
(956) 761-2649
Listed By:
Robert N. Pinkerton · License #0678792
(956) 572-0521
Added: Sep 7
Last Checked: Sep 9 at 4:06AM
MLS# 106767
Copyright © 2026 South Padre Island Board of Realtors. All rights reserved. All information provided by the listing agent/broker is deemed reliable but is not guaranteed and should be independently verified.
Investment Insights
Based on property information with market context.
This quadplex includes a primary residence and three individual efficiency cottages, creating four separate living spaces within 3508 square feet. The improvements use block and brick construction and include storage, tile and carpet flooring, ceiling fans, washer/dryer hookups, and furnished interiors. On-site features include an attached garage, patios, a private yard, and a sprinkler system, with appliances including refrigerators, dishwashers, disposals, and microwaves.
The property occupies three individual city lots near Port Isabel’s Historic district and has bay views. A central area between the residences provides additional outdoor space within the existing layout. MF zoning supports the property’s multifamily classification.
The property occupies three individual city lots near Port Isabel’s Historic district and has bay views. A central area between the residences provides additional outdoor space within the existing layout. MF zoning supports the property’s multifamily classification.
Key Highlights
- Main residence plus three efficiency cottages
- 3508 square feet across three individual city lots
- MF zoning
Financial Insights
Estimated NOI and Cap Rate
NOI = area × lease_rate × (100 − vacancy) / 100 × (1 − expense_ratio). Net Operating Income — what the owner takes home each year before mortgage payments and income tax. Effective rent (asking rent minus vacancy losses) minus operating costs (taxes, insurance, maintenance, management).
NOI / Yr
$28,942
Cap rate = NOI / list price × 100. Capitalization rate — annual return on a fully cash purchase, before financing. NOI divided by price. Higher means more income per dollar invested, but usually also more risk or older condition. 5–8% is typical for stabilized commercial property; double digits often signal distressed deals.
Cap Rate
3.86%
Suggested Prices Based on Cap Rates
Cap rates vary significantly by property type, market, and asset quality.
Typical U.S. stable-market ranges:
Multifamily — 4.5% to 6.5% (Class A in primary markets often sub-5%; Class C in secondary markets 6%+)
Industrial / Logistics — 5.0% to 7.0% (compressed heavily in recent years due to e-commerce demand)
Office — 6.5% to 9%+ (wide spread post-2020; CBD Class A vs. suburban Class B varies dramatically)
Retail — 5.5% to 8.5% (grocery-anchored on the low end, unanchored strip centers higher)
Hospitality / Hotels — 7.5% to 10%+ (higher due to operational risk)
Self-Storage — 5.5% to 7.5%
Medical Office — 6.0% to 7.5%
Net Lease (single tenant, credit) — 5.0% to 7.0% depending on tenant credit and lease term
Rules of thumb:
Primary markets (NYC, SF, LA, Boston, DC) trade at lower cap rates than secondary/tertiary markets, often by 100–200 bps (bps, aka basis points; 1 bp = 0.01%).
Class A assets trade ~50–150 bps tighter than Class B, and Class B tighter than Class C.
Cap rates move inversely with price — a lower cap rate means a higher price for the same NOI.
Spread to the 10-year Treasury is a common benchmark; historically 200–400 bps over the 10-year.
Cap Rate 5%
$578,840
$578.8K
Cap Rate 7%
$413,457
$413.5K
Cap Rate 9%
$321,578
$321.6K
Market Conditions
NOI Build-Up for 3,508 SF
Vacancy — income lost from leasable area expected to sit empty during the year, subtracted from gross rent.
EGI (Effective Gross Income) — gross rent minus vacancy losses, the realistic income before paying operating costs.
OpEx (Operating Expenses) — recurring costs to operate the property (property tax, insurance, utilities, maintenance, management); excludes financing and capital improvements.
NOI (Net Operating Income) — income a property generates after operating costs but before financing and taxes.
Gross rent
$44.2K $12.60/SF
− Vacancy
−$2.9K −$0.81/SF
EGI
$41.3K $11.79/SF
− OpEx
−$12.4K −$3.54/SF
NOI
$28.9K $8.25/SF
Area
Cameron County, TX
Vacancy
6.46%
Lease Rate
$12.60 /SF/Yr
Expense Ratio
30.00%
Simulate Cap Rate and NOI
Suggested Prices Based on Cap Rates
Cap rates vary significantly by property type, market, and asset quality.
Typical U.S. stable-market ranges:
Multifamily — 4.5% to 6.5% (Class A in primary markets often sub-5%; Class C in secondary markets 6%+)
Industrial / Logistics — 5.0% to 7.0% (compressed heavily in recent years due to e-commerce demand)
Office — 6.5% to 9%+ (wide spread post-2020; CBD Class A vs. suburban Class B varies dramatically)
Retail — 5.5% to 8.5% (grocery-anchored on the low end, unanchored strip centers higher)
Hospitality / Hotels — 7.5% to 10%+ (higher due to operational risk)
Self-Storage — 5.5% to 7.5%
Medical Office — 6.0% to 7.5%
Net Lease (single tenant, credit) — 5.0% to 7.0% depending on tenant credit and lease term
Rules of thumb:
Primary markets (NYC, SF, LA, Boston, DC) trade at lower cap rates than secondary/tertiary markets, often by 100–200 bps (bps, aka basis points; 1 bp = 0.01%).
Class A assets trade ~50–150 bps tighter than Class B, and Class B tighter than Class C.
Cap rates move inversely with price — a lower cap rate means a higher price for the same NOI.
Spread to the 10-year Treasury is a common benchmark; historically 200–400 bps over the 10-year.
Cap Rate 5%
$578,840
Cap Rate 7%
$413,457
Cap Rate 9%
$321,578
Alternative Uses
Best Use
Multifamily LT 5
$413.5K
$361.8K – $482.4K
NOI $28,942 @ 7.0% cap · market cap 3.86%
Second Best
Apartment 5plus
$379.2K
$331.8K – $442.4K
NOI $26,541 @ 7.0% cap · market cap 3.54%
Theoretical Best
Healthcare Medical
$604.0K
$528.5K – $704.7K
NOI $42,281 @ 7.0% cap · market cap 5.64%
Zoning and permitted uses should be independently verified with authorities.
Property Analytics
Property Profile
Current Use
Lease Details
4
Residential units
Location Intelligence
Trade Area within ½ mile
528
Businesses Nearby
Explore this area
Business Placement
Demographics for 78578, TX
10,076
Population
6,391
Households
1.6
Avg Household Size
45
Median Age
24%
College-Educated
83%
High-School Grad
57.0 sq mi
ZIP Area
177
Density / Sq Mi
$52,041
Median Household Income
$36,896
Median Earnings
$763
Median Rent
$193,700
Median Home Value
Market
Vacancy Rate% for Multifamily in South region
Questions? Ask Rey
Realmo’s AI knows this listing — price, zoning, demand, history. Ask anything.
Frequently Asked Questions
What type of property is this?
Quadplex - Four separate residences offer a maintained block-and-brick property with an attached garage, storage, and private outdoor areas.
Where is this quadplex located?
The property is located at 310 Harbor Light Port Isabel, TX.
What is the asking price?
The asking price for this property is $750,000.
What are key features of this property?
This property features: Main residence plus three efficiency cottages; 3508 square feet across three individual city lots; MF zoning
