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$2,400,000 New to Website

  • For Sale
  • Active
  • Single Family
  • 7 Beds
  • 5 Full Baths
  • 2 Partial Baths
  • 5,291 Sq. Ft.
  • 2 Car Garage
  • Updated 1 day ago
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Welcome to this stunning custom home offering walkable convenience and refined living, complete with a finished basement and fully independent ADU. Move-in ready with designer blinds and mature landscaping. Step out the back door to Whole Foods, Super Target, the McCaslin RTD station, and the newly rebuilt Founder's Park. From the front, enjoy Downtown Superior and miles of open space trails. Located on a corner lot, the home features an open floor plan, seamless indoor-outdoor living, and mountain views. Generous rooms, sweeping windows, and 10-foot ceilings throughout fill the home with natural light. The main level includes rich wood flooring, a great room with fireplace, and a chef's kitchen that includes a large island and striking countertops. Between the home and garage, a secluded landscaped courtyard patio with privacy fencing creates a blissful outdoor retreat. A custom floating staircase leads to two spacious upstairs bedrooms that are in addition to the primary suite---each with its own bath, plus a laundry room and sitting area opening to a covered balcony. The primary suite offers a five-piece bath with soaking tub, Porcelanosa-tiled walk-in shower, and expansive walk-in closet. A main-level ensuite bedroom provides flexible living and use options. The finished basement adds a rec room, wet bar, gym space, and two bedrooms.The detached two-car garage includes a finished ADU with bedroom, bath, full kitchen, washer/dryer, and balcony---ideal for guests, office, or rental use. Extras include fire sprinkler suppression system, indoor and outdoor EV charging, and hot tub. Turnkey home with quick access to Highway 36, Boulder, Denver, and DIA!

Full Property Details for 403 W William St

General

  • Price: $2,400,000
  • Taxes: $9,899 (2025)
  • Status: Active
  • Type: Single Family
  • Source: IRES
  • MLS ID: 1053262
  • Updated: 3/15/2026
  • Added to Site: 1 day(s) ago

Interior

  • Interior Features: Eat-In Kitchen, Open Floorplan, Pantry, Walk-In Closet(s), Wet Bar
  • Fireplace: Yes
  • Fireplace(s): Gas, Living Room
  • Appliances: Gas Range, Dishwasher, Refrigerator, Bar Fridge, Washer, Dryer, Microwave

Rooms

Bathrooms

  • Total Bathrooms: 7
  • Full Bathrooms: 5
  • 3/4 Bathrooms: 1
  • Half Bathrooms: 1
  • Main Floor Baths: 1
  • Basement Baths: 1

Bedrooms

  • Total Bedrooms: 7

Additional Information

  • Security/Safety: Fire Sprinkler System, Fire Alarm

Exterior

  • Exterior Features: Sprinkler System, Balcony, Hot Tub, Carriage House
  • Porch/Patio/Deck: Patio

Parking

  • Garage: Yes
  • Attached garage: Yes
  • Garage Spaces: 2
  • Parking Features: Attached
  • Garage Description: Attached

Location

  • Area: Superior
  • County: Boulder
  • Subdivision: Superior West

School Information

  • School District: Boulder Valley Dist RE2
  • Elementary School: Monarch
  • Middle School: Monarch
  • High School: Monarch

Heating & Cooling

  • Cooling Type: Central Air, Wall/Window Unit(s)
  • Heating Type: Forced Air, Heat Pump

Utilities

  • Gas: Yes
  • Gas: Xcel
  • Sewer: Public Sewer
  • Water: City
  • Utility Description: Natural Gas Available, Electricity Available

Structural Information

  • Architectural Style: In-Law Area
  • Builder: Colson Builders
  • Model: custom
  • Construction: Frame, Metal Siding, Composition
  • Exterior Const.: Frame, Metal Siding, Composition
  • Basement: Yes
  • Basement Desc.: Partially Finished
  • Roof: Composition
  • Windows: Window Coverings
  • Square Feet: 5,291
  • Sq. Ft. Source: Other
  • Living Area: 5,185 Sq. Ft.
  • Year Built: 2023

Lot Features

  • Property View: Mountain(s), Hills, Plains View
  • Mountain views: Yes
  • Lot Size (Acres): 0.16
  • Lot Size (Sq. Ft.): 6,884
  • Fence: Yes
  • Lot Features: Corner Lot, Level, House Faces South, Street Light, Alley
  • Potential Use: Single-Family, Multi-Family, Additional Units
  • Zoning: RL
  • Fencing (Description): Fenced, Wood

Green Features

  • Energy Efficient: Windows, High Efficiency Furnace, Thermostat

Financial Considerations

  • Tax Amount: $9,899
  • Tax Year: 2025
  • Terms: Cash, Conventional

Disclosures and Reports

  • Special Conditions: Licensed Owner
  • Exclusions: Seller's personal property.
  • Property ID: R0617502

Listed by Buyers' Slice Realty (303) 376-6111

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Listing agent

— 403 W William St —

  • Buyers' Slice Realty

    303-376-6111

3033766111

Get Pre-Approved Today

Be ready to buy your new home!

with our affiliated lender
NMLS#: 1598647

Get Pre-Approved

Be ready to buy your new home!

with our affiliated lender
NMLS#: 1598647

Get Pre-Approved

Schools serving 403 W William St

School District:Boulder Valley School District Re-2
NameGradesDistance
Monarch K-8 School
263 Campus Drive, Louisville, CO 80027
6-81.4 mi
Monarch High School
329 Campus Drive, Louisville, CO 80027
9-121.5 mi
Disclaimer: School attendance boundaries provided by ATTOM Data Solutions and are for reference only. Contact the school directly to verify enrollment eligibility.

Price & Sales History for 403 W William St Get Price Alerts and Save Property

Date
Details
Price
Change
Source
3/15/2026
Listed
$2,400,000
42.5%
MLS
2/22/2024
Sold
$1,684,250
—
Public Record
Get Price Alerts and Save Property
Disclaimer: Historical sales information is derived from public records provided by the county offices. Information is not guaranteed and should be independently verified.

Tax History for 403 W William St

Year
Property Taxes
Change
Tax Assessment
Change
2025
$9,899
31%
$89,082
23%
2024
$7,534
—
$72,708
—
Disclaimer: Historical tax information is derived from public records provided by the county offices. Information is not guaranteed and should be independently verified.

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*These costs are estimates, and the interest rates assume exceptional credit standing.

Be ready to buy your new home!

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NMLS#: 1598647

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Listed by Buyers' Slice Realty (303) 376-6111

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403 W William St, Superior, CO 80027 (MLS# 1053262) is a Single Family property with 7 bedrooms, 5 full bathrooms and 2 partial bathrooms. 403 W William St is currently listed for $2,400,000 and was received on March 15, 2026. Want to learn more about 403 W William St? Do you have questions about finding other Single Family real estate for sale in Superior? You can browse all Superior real estate or contact a Coldwell Banker agent to request more information.

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