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    Historic Portsmouth Office Building For Sale Title is generated by Realmo AI

    144 Washington Street, Portsmouth, NH 03801

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    For Sale
    $3,300,000

    Commercial For Sale - Portsmouth, NH

    Lot size:
    0.25 Acres
    Added:
    Dec 15, 2025
    Days on Market:
    157
    Last Refresh:
    May 21 at 3:06 pm

    Property Features for 144 Washington Street

    General Information

    Property type
    Commercial Sale
    Property subtype
    Other
    Zoning
    MRO
    Rooms
    Basement
    Basement Y/N
    1
    Standard status
    Active
    Lot size
    0.25 Acres

    Taxes and HOA fees

    Tax Annual Amount
    16937

    Utilities

    Heating system
    Baseboard, Hot Water (Heating), Natural Gas

    Building Details

    Year built
    1747
    Number of units
    9
    Roof type
    Wood
    Architectural style
    Other

    We can help!

    Listing Contact
    Wayne Semprini

    Listing agent Wayne Semprini

    Listing office The Aland Realty Group 175 Market Street., Portsmouth, NH

    Listing date Dec 15, 2025

    MLS# 5072167 Listing URL

    Copyright © 2026 PrimeMLS. All rights reserved. All information provided by the listing agent/broker is deemed reliable but is not guaranteed and should be independently verified.

    HighLights

    • Landmark Federal‑style residence in Portsmouth's historic Puddle Dock area with sweeping views.
    • One of the largest privately owned parcels in Portsmouth's South End with off‑street parking and potential for garage/carriage house.
    • Prime location: five‑minute walk to Market Square, Portsmouth's cultural epicenter.
    • Historic architectural details: genuine moldings, original eight‑panel doors, and distinctive dental moldings.
    • Versatile property suitable for residential or professional use, currently configured as professional offices.
    • Third floor with exposed beams and wide pine floors, ideal for a private office.

    Overview

    The Leonard Cotton House, a Portsmouth landmark with over two centuries of history, is situated in Portsmouth’s historic Puddle Dock area. This Federal-style residence offers views across Strawberry Banke Historic Museum, Prescott Park, and the Piscataqua River. As one of the largest privately owned parcels in Portsmouth’s South End, the 0.25-acre lot includes off-street parking with room to construct a garage or carriage house. Located on the corner of Hancock and Washington Streets, the property is a five-minute walk from Portsmouth’s Market Square. Architectural details include moldings, original eight-panel doors, and dental moldings. The third floor features exposed beams and wide pine floors, creating a private office space. The property has served as law offices for over forty years and is currently configured as professional offices. It is suitable for any business seeking a central Portsmouth location. The zoning is MRO.
    Property Profile Insight Report Location Intelligence

    Current Use by Public Records

    Durbin Law Offices, ... Law Firm Loughlin Peter J Law Firm Colby Gamester Consultant Creed Michael Insurance Agency

    Suggested Use

    Restaurant Law Firm Real Estate Agency Spa & Massage Center Dental Office Hair Salon Nail Salon Food Market Grocery & Convenience Store Pharmacy

    Zoning and permitted uses should be independently verified with local authorities.

    Location Insight

    • Map
    • Local Demand
    City
    Portsmouth
    County
    Strafford
    State
    New Hampshire
    Longitude
    -70.7541535
    Latitude
    43.0747813

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    FAQs

    What type of property is this?
    Office building - Landmark Portsmouth building, ideal for professional offices or business.
    Where is this office building located?
    The property is located at 144 Washington Street Portsmouth, NH.
    What is the asking price?
    The asking price for this property is $3,300,000.
    What are key features of this property?
    This property features: Landmark Federal‑style residence in Portsmouth's historic Puddle Dock area with sweeping views.; One of the largest privately owned parcels in Portsmouth's South End with off‑street parking and potential for garage/carriage house.; Prime location: five‑minute walk to Market Square, Portsmouth's cultural epicenter.
    (603) 490-4400
    We can help!
    Listing Contact
    Wayne Semprini
    Learn More
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    Realmo Value Estimations

    Realmo estimates a property’s market value using a proprietary methodology that incorporates public data and user-submitted information. This cumulative value is generated by integrating a variety of conventional and innovative methods. 

    Disclaimer

    These figures are not official appraisals and should not be used as a substitute for a valuation performed by a licensed appraiser.
    Actual market value may differ due to factors not captured in the data. Estimates are offered for informational purposes only, and users should conduct independent research before making financial or investment decisions.
    By using this feature, you acknowledge that Realmo is not responsible for actions taken based on these estimates.

    AI approach

    Realmo AI Method estimates property value using machine learning models trained on millions of comparable listings, transactions, and market signals. It analyzes property features, location intelligence data, and current market dynamics to predict the most probable market value in real time.

    Realmo CapRate Calculation

    Realmo calculates the Capitalization Rate (Cap Rate) to help estimate a property's potential return on investment. The Cap Rate is a fundamental metric in commercial real estate that measures the relationship between a property's net operating income and its market value.

    How We Calculate Cap Rate

    Cap Rate Formula:
    Cap Rate (%) = (Net Operating Income / Property Value) × 100

    Net Operating Income (NOI) Formula:
    NOI = Area × Lease Rate × (1 - Vacancy Rate) × (1 - Operating Expense Ratio)

    Components

    Net Operating Income (NOI) represents the annual income a property generates after operating expenses:

    • Area: Building square footage from property records
    • Lease Rate: Annual $/sqft based on market data for the property type and geographic location
    • Vacancy Rate: Percentage of unoccupied space based on market data for the property type and location
    • Operating Expense Ratio: Operating costs as a percentage of income, varies by property type

    Property Value is derived from:

    • Recent sale price (if available)
    • Statistical models using comparable sales
    • AI-powered valuation estimates

    Example Calculation

    For a 100,000 sqft Office Building:

    • Lease Rate: $25.00/sqft/year (market data for Office in this area)
    • Vacancy Rate: 8% (market data for Office in this area)
    • Operating Expense Ratio: 35% (typical for Office properties)
    • Property Value: $15,000,000

    Step 1: Calculate NOI

    NOI = 100,000 × $25.00 × (1 - 0.08) × (1 - 0.35)
    NOI = 100,000 × $25.00 × 0.92 × 0.65
    NOI = $1,495,000/year

    Step 2: Calculate Cap Rate

    Cap Rate = ($1,495,000 / $15,000,000) × 100
    Cap Rate = 9.97%

    Property Type Considerations

    Net Operating Income calculations vary by property type due to different operating expense ratios:

    • Office: Higher expenses (30-40%) for HVAC, utilities, maintenance
    • Retail: Moderate expenses (25-35%) for common area maintenance
    • Industrial/Warehouse: Lower expenses (15-25%) for minimal tenant services
    • Multifamily: Moderate expenses (35-45%) including property management
    • Self-Storage: Lower expenses (25-35%) due to minimal maintenance

    Market lease rates and vacancy rates are specific to each property type and geographic location, reflecting local market conditions.

    Disclaimer

    These calculations are estimates for informational purposes only and should not be used as a substitute for professional financial analysis or appraisal.

    • Cap Rate calculations depend on market data that may change over time
    • Actual operating expenses, lease rates, and vacancy rates may differ from market averages
    • Individual property conditions, lease terms, and tenant quality significantly impact actual NOI
    • Property value estimates are approximations and not official appraisals
    • Cap rates vary widely by market, property condition, and investment risk profile

    Professional Guidance Recommended: Before making any investment or financial decisions, consult with licensed appraisers, commercial real estate brokers, and financial advisors who can evaluate your specific property and circumstances.
    By using this feature, you acknowledge that Realmo is not responsible for investment decisions or actions taken based on these estimates.

    Cap approach

    Capitalization Method calculates value based on estimated net operating income (NOI) and applying a market-based capitalization rate (cap rate), we estimate what a typical investor might be willing to pay for it.

    Comparable approach

    Comparable estimate is based on recent sales of similar nearby properties, adjusted for factors like size, condition, and location.

    Relative

    Relative property class coefficient uses factors that account for typical price differences between various asset types (e.g., retail vs. industrial) to provide a more accurate market-aligned estimate.

    Geo

    Comparable Sales Method, enhanced by Geo coefficients — location-based adjustment factors that reflect differences in price levels across neighborhoods, cities, or regions ensuring a more accurate, market-sensitive valuation.

    Stat Estimate

    This method estimates value based on actual market adjusted recent (~5 years) sales of comparable properties around by location and property type.

    • Ranges - area data calculated by industry standard IQR Outlier Removal Method
    • Range-from: 75% of all similar sales ($/sqft) are above this value
    • Range-to: 75% of all similar sales ($/sqft) are below this value
    AI Estimate

    This method estimates value based on AI market estimation of comparable properties around by location and property type.

    • Ranges - area data calculated by industry standard IQR Outlier Removal Method
    • Range-from: 75% of all estimations ($/sqft) are above this value
    • Range-to: 75% of all estimations ($/sqft) are below this value
    Alternative use

    Estimate considers the property’s potential value if used for a different purpose-based on zoning, demand, and market feasibility.

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