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303 W William St, Superior (Louisville), CO 80027 Property Records

Boulder County property record for 303 W William St, Superior, CO 80027

Property Summary

Property TypeSingle Family Home
Details2 bd · 1.75 ba · 1,482 sqft · built 2026
Lot Size0.154 acres (6,716 sqft)
OwnerIndividual Name on File
Last Sale$930,000 (Jun 2026)
Tax Bill$2,273 (2025)
Deeds & MortgagesJun 2026 Sale & Mortgage
Nov 2025 Sale & Construction Loan
Flood ZoneZone X (minimal risk)
APN1577-24-0-08-007

Property Details

APN / Parcel Number

Primary APN1577-24-0-08-007
Alternative APNs
  • R0029307
  • 0029307

Interior

Bedrooms2 Beds
Full Baths1.75 Baths
Half Baths1 Half Bath
Total Rooms5 Rooms
Stories1 Story
Building Area1,482 sqft Living Area
Gross Area2,574 sqft
1st Floor Area195 sqft
Interior WallsWallboard/Drywall

Exterior

Year BuiltBuilt 2026
Effective Year BuiltEffective 2026
Architectural StyleRanch
Exterior MaterialComposition/Composite
Construction TypeFrame
Roof MaterialAsphalt
Lot Area6,716 sqft (0.154 acres)
Garage TypeAttached
Garage Area1,092 sqft
Parking Spaces2 Parking Spaces
PorchPorch
Porch Area56 sqft

Utilities, Heating & Cooling

Cooling SystemCentral
Heating SystemFloor/Wall Furnace

Location & Zoning

Account NumberR0029307
Street Address303 W WILLIAM ST
CitySUPERIOR
StateCO
Zip80027-9647
Property CategoryResidential
Property TypeResidential > Single Family > Home
Legal DescriptionLOT 11 BLK D SUPERIOR
Legal Range70
Legal Township1S
Legal Section24
Legal SubdivisionSUPERIOR & SOUTH - SP
Legal BlockD
Legal Lot Number11
JurisdictionBOULDER CO
Township / Civil DivisionBOULDER
Census Block Group1
Census Block1022
Census Tract60602

Owner

303 W William St is owned by an individual who bought it in June 2026.

Source: Boulder County records, as of September 18, 2026

Owner of RecordIndividual Name on File
Mailing Address109 3RD AVE, SUPERIOR, CO 80027-9662
Owner TypeIndividual
VestingJoint Tenants

Owner names and exact recorded amounts are on file and can be viewed instantly on this page with a free 10-day trial.

Deeds, Mortgages & Sale History

DateDocument
Jun 22, 2026Special Warranty Deed, Transfer · Conventional Mortgage
ZIONS BANCORPORATION NA
Nov 17, 2025Warranty Deed, Construction Loan · Construction Mortgage
FIRSTBANK

Assessor's Deed Record

Deed NamesName on Deed
Last SaleJun 22, 2026 · Amount on File
Deed SaleJun 22, 2026 · Amount on File
Prior SaleNov 17, 2025 · Amount on File
Deed Document Number20264136776
Prior Transfer DateMar 1, 1995
Prior Transfer Doc0001531808
Record UpdatedOct 29, 2026

June 2026: Special Warranty Deed, Transfer

Document TypeSpecial Warranty Deed
JurisdictionBOULDER CO
Recording DateJun 22, 2026
Property Address303 W WILLIAM ST, SUPERIOR, CO 80027-9647
Document Number0004136776
Instrument DateJun 18, 2026
Instrument20264136776
Transaction TypeTransfer
Record UpdatedAug 26, 2026
Title CompanyLAND TITLE

Transaction

AmountAmount on Record
DownpaymentDownpayment on Record
Loan-to-Value (LTV)LTV on Record
Tax$9,393.00
Amount AccuracyCalculated from Transfer Tax
Additional
  • Arm's Length

Transferred From (Grantor/Seller)

NameVerified Name

Transferred To (Grantee/Buyer)

NameVerified Name
RelationshipJoint Tenants
Address109 3RD AVE, SUPERIOR, CO 80027-9662

Mortgage

Document Number0004136777,
DateJun 22, 2026
Instrument20264136777
Lender
NameZIONS BANCORPORATION NA
Agreement
TypeConventional Mortgage
AmountAmount on Record
Term360 Months
DueJul 1, 2056
Interest
Rate TypeAdjustable Rate
Rate5.88%
Initial TypeAdjustable Rate
AdjustableAdjustable Rate Rider
Max Rate-1%

November 2025: Warranty Deed, Construction Loan

Document TypeWarranty Deed
JurisdictionBOULDER CO
Recording DateNov 17, 2025
Property Address303 W WILLIAM ST, SUPERIOR, CO 80027-9647
Document Number0004109982
Instrument DateNov 17, 2025
Instrument4109982
Transaction TypeConstruction Loan
Record UpdatedDec 11, 2025
Title CompanyLAND TITLE GUARANTY COMPANY IN, LAND TITLE GUARANTEE COMPANY

Transaction

AmountAmount on Record
Loan-to-Value (LTV)LTV on Record
Tax$41.00
Amount AccuracyFull Amount Stated
Additional
  • Arm's Length

Transferred From (Grantor/Seller)

NameVerified Name
Address303 W WILLIAM ST, SUPERIOR, CO 80027-9647

Transferred To (Grantee/Buyer)

NameVerified Name
Address411 W CHARLES ST, SUPERIOR, CO 80027-9623

Mortgage

Document Number0004109983
DateNov 17, 2025
Instrument4109983
Lender
NameFIRSTBANK
TypeBank
Agreement
TypeConstruction Mortgage
AmountAmount on Record
Term19 Months
DueJun 1, 2027

Tax Assessment & Valuation

The 2025 property tax bill for 303 W William St was $2,273, up 91.2% from the year before.

Source: Boulder County assessment roll, as of September 18, 2026

Property Jurisdictions

TypeName
StateColorado
CountyBoulder County
MunicipalitySuperior Town
Unified School DistrictBoulder Valley School District RE-2 (PK - 12)

Tax Bill & Assessment History

YearTax BillAssessed ValueAssessed Market Value
2026$20,037 (-15.72%) Land $20,037$327,400 (-13.93%) Land $327,400
2025$2,273.00 (+91.17%)$23,775 (+107.03%) Land $23,775$380,400 (+68.02%) Land $380,400
2024$1,189.00 (+1.36%)$11,484 (-24.29%) Land $11,484$226,400 (-) Land $226,400
2023$1,173.00 (+109.46%)$15,169 (+182.9%) Land $15,169$226,400 (+193.45%) Land $226,400
2022$560.00$5,362 Land $5,362$77,150 Land $77,150

Assessed value is set for property tax purposes, not a market price estimate; it is a fraction of this property's market value.

Flood

FEMA maps place 303 W William St in Zone X, an area of minimal flood risk, within 500 ft of a high-risk flood zone.

Source: FEMA National Flood Hazard Layer, effective October 14, 2026 · OpenFEMA NFIP redacted claims and policies, as of September 2026

FEMA Flood ZoneZone X
minimal risk
Nearest Special Flood Hazard AreaZone AE, within 500 ft
Flood Insurance RequirementNot required
lenders may require it
Community Rating SystemClass 5 (25% premium discount)
Nearby Flood Policies3 in force
Nearby Flood Claims1 (2013)
Most Recent ClaimSep 2013 · Severe Storms, Flooding, Landslides, And Mudslides

Values are read at the parcel center point; flood claims are located to the census block group, not this parcel; lenders make the official flood determination.

Wildfire

Wildfire risk around 303 W William St is moderate, ranking above 64% of the US, with a 0.3% annual chance of wildfire.

Source: USDA Forest Service Wildfire Risk to Communities (2nd edition), as of 2024

Wildfire RiskModerate
above 64% of the US · above 55% of Colorado
Wildfire Likelihood0.3% annual chance
ExposureIndirect
within ember reach
Adjoins Burnable LandYes

Values cover an area roughly 900 ft across, not the parcel itself; insurers use their own ratings.

Drinking Water

Source: EPA Safe Drinking Water Information System, as of September 2026

Water SystemSUPERIOR MD NO 1
serves 17,900 people · EPA ID CO0107725
Water SourceSurface water
Last State InspectionFeb 2025
LeadUnder 1 ppb (2023–2025)
action level 15 ppb

Violations Reported to EPA

Water QualityTreatment failure
resolved · Dec 2021
Treatment and ProcedureNone
last 10 years
Monitoring and ReportingNone
last 3 years

Results are for the whole water system, not water tested at this address; lead at the tap also depends on the building's own pipes.

Internet Providers

Source: FCC Broadband Data Collection, based on 225 locations within half a mile, as of December 31, 2025

ProviderMax Down / Up (Mbps)
Xfinity
Cable		2,000 / 2,000
CenturyLink
Fiber · DSL in parts of the area		2,000 / 1,000
LiveWireNet
Fixed Wireless		250 / 100

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