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Single Family ResidenceResidential
$80,789$98 / ft²
TopHap EstimateOur estimate of what this home would sell for today, based on nearby sales, the home's size and features, and local price trends. It is a starting point, not an appraisal.· confidence 86How well the pricing models agreed with each other on this home. Higher means the estimate rests on stronger, more consistent data.· as of Oct 21, 2026

518 WILLIAM ST

ALTON, IL 62002
2
Beds
1
Baths
826 ft²
Living AreaTotal finished area of the structures, from county records. Some counties include shared space like hallways or a building gym, so it may not match a listing.
2,430 ft²
Lot SizeThe size of the land the home sits on, from county records.
1950
Year BuiltThe year the home was originally built, according to county records.
1
StoriesHow many floors the home has above ground.
5
RoomsThe total room count in county records. Counties differ on which rooms they count, so compare it loosely.

Valuation

$81K
$70K low$92K high

Tax & Assessment

Property TaxThe property tax billed for this tax year. It usually pays for schools, roads, and local services.$1,528 (2025)
Assessed ValueThe value the county assigns to this home to calculate property tax. It is often lower than what the home would sell for.$25,090 (2025)
Assessed LandThe share of the county's assessed value that comes from the land itself, not the buildings.$530
Assessed ImprovementsThe share of the county's assessed value that comes from the buildings and other structures on the land.$24,560
Previous AssessedThe county's assessed value from the year before, useful for seeing how the assessment changed.$22,700
Assessor Market ValueThe county assessor's own opinion of market value. It is separate from our estimate and updates on the county's schedule.$75,270

Climate Risk

Overall riskThe average of the five hazard scores below, on a 0 to 100 scale. Higher means greater projected risk over the coming decades.34
1
FloodProjected flooding risk from rivers, heavy rain, and storm surge, scored 0 to 100. Higher is riskier.
14
WildfireProjected wildfire risk, scored 0 to 100, based on how much land burns in a typical year. Higher is riskier.
83
HeatProjected heat risk, scored 0 to 100, based on how many extremely hot days a year are expected. Higher is riskier.
70
StormProjected risk from heavy rainstorms, scored 0 to 100, based on how often extreme rainfall is expected. Higher is riskier.
4
DroughtProjected water shortage risk, scored 0 to 100. Higher means more strain on the local water supply.

Scores 0–100; higher = greater projected risk.

Property Facts

Property TypeThe broad category the county puts this property in, such as residential or commercial.Single Family Residence
StyleThe architectural style of the home, such as ranch or colonial.Conventional
CountyMADISON
Lot (acres)The size of the land the home sits on, from county records.0.06
ConstructionThe main material the home's frame and walls are built from.Frame (Unspecified)
HeatingThe type of heating system in the home.Yes
CoolingThe type of cooling or air conditioning in the home.Central
PoolWhether the property has a pool, and what kind, such as in-ground.No
FeaturesExtra features found in county records. Records are not complete everywhere, so a missing feature does not always mean the home lacks it.Shed · 150 ft²

Assigned SchoolsThe public schools this address is zoned for. Boundaries change, so confirm with the district before you count on it.

M
Alton Middle SchoolD
Middle · Grades 6–8 · 2.0 mi
E
Gilson Brown Elementary School
Elementary · Grades KG–1 · 3.0 mi
H
Alton High SchoolD+
High · Grades 9–12 · 3.4 mi

District: Alton Community Unit School District 11

Neighborhood · ZIP 62002These are comparison scores, not percentages. 100 equals the national average, so 150 means about 50% above average.

CrimeLocal crime compared with the rest of the country, where 100 is average. It reflects things like population density, income, and how crime gets reported.135
Air pollutionOverall air pollution compared with the rest of the country, where 100 is average. Lower is cleaner.85
EarthquakeEarthquake risk and likely building damage compared with the rest of the country, where 100 is average. Scores can run far above 100.125

Index scale: 100 = US average (tick). Lower is better.

Homes occupiedThe share of homes here that someone lives in. The rest sit empty, including vacation and for-sale homes.89%
Bachelor's or higherThe share of adults 25 and older whose highest degree is a bachelor's degree.16%
Poverty rateThe share of people whose household income falls below the federal poverty line, which varies by family size.19%
UnemploymentThe share of men 16 and older who are out of work and actively looking. Only men are counted in this figure.1.1%
PopulationHow many people live in this area.28,813
DensityPeople per square mile. Higher numbers mean a more crowded, urban area.738 / mi²
Median incomeThe middle household income here — half of households earn more, half earn less.$61,207
Average incomeThe average household income. It runs higher than the median when a few high earners pull it up.$78,082
Average tempThe average temperature here across a full year.55°F
Annual precipHow much rain and melted snow falls here in a typical year.39 in
SunshineThe share of daylight hours that get direct sun in a typical year, counting cloud cover.59%

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Data by ATTOM. Valuations are automated estimates, not appraisals. Photos from Google Street View and may not depict the current property state.

How this home compares

518 William St measured against every home in its neighborhood, its ZIP code and its county, using county assessor records refreshed nightly. A home can stand out in one of those areas and look ordinary in another, because each one holds a different mix of homes.

  • Worth less than 86% of homes in Madison County
  • Costs less per square foot than 82% of homes in Madison County
  • Smaller than 84% of homes in Madison County
  • Among the smallest lots in Madison County
  • Older than 68% of homes in Madison County

What homes are worth in Alton 62002

Each bar is how many homes fall in that price range. The marker is this home.

This home
$29K$461K

This home is worth more than 33% of homes in Alton 62002.

How it measures up in Alton 62002

The dot is this home. The mark in the middle is the typical home in Alton 62002.

Estimated value$80,789
CheaperTypical $107,229Pricier

Pricier than 33% of homes nearby

Price per ft²$98
CheaperTypical $106Pricier

Pricier than 44% of homes nearby

Living area826 ft²
SmallerTypical 1,008 ft²Bigger

Bigger than 24% of homes nearby

Lot size2,430 ft²
SmallerTypical 0.19 acBigger

Smaller than almost all homes nearby

Year built1950
OlderTypical 1948Newer

Newer than 57% of homes nearby

How 518 William St ranks against every home in each area.
MeasureThis homeAlton 62002Madison County
Estimated valuepricier than$80,78933% of homes14% of homes
Price per ft²pricier than$9844% of homes18% of homes
Living areabigger than826 ft²24% of homes16% of homes
Lot sizebigger than2,430 ft²almost no homesalmost no homes
Year builtnewer than195057% of homes32% of homes

About 518 William St

How much is 518 William St, Alton, IL worth?

The TopHap Estimate for 518 William St, Alton, IL is $80,789 as of Oct 21, 2026. The likely range is $69,720 to $91,858. The estimate is modelled from recorded sales, assessments and the property's own characteristics — it is not an appraisal.

When did 518 William St, Alton, IL last sell?

518 William St, Alton, IL last sold on Jan 1, 1900, according to the county's recorded deed.

How big is 518 William St, Alton, IL?

518 William St, Alton, IL has 2 bedrooms, 1 bathrooms, 826 square feet of living space and a 0.06-acre lot.

When was 518 William St, Alton, IL built?

518 William St, Alton, IL was built in 1950, making it 76 years old. It is a conventional home. The building has 1 story.

What schools serve 518 William St, Alton, IL?

518 William St, Alton, IL is assigned to Alton Middle School (middle), rated D; Gilson Brown Elementary School (elementary); Alton High School (high), rated D+. All sit in Alton Community Unit School District 11. Attendance boundaries change — confirm with the district before relying on an assignment.

How does 518 William St, Alton, IL compare to other homes in Alton 62002?

Among the 12,598 homes in Alton 62002, it is worth more than 33% of them ($80,789 against a typical $107,229), its price per square foot is higher than 44% of them ($98 against a typical $106), it is bigger than 24% of them (826 ft² against a typical 1,008 ft²), its lot is bigger than almost none of them (2,430 ft² against a typical 0.19 ac) and it is newer than 57% of them (1950 against a typical 1948). Measured against all of Madison County, it is worth more than 14% of homes there. These shares are recounted nightly from the full county assessor record for each area, not from active listings.

What are the property taxes on 518 William St, Alton, IL?

The 2025 property tax bill for 518 William St, Alton, IL was $1,528. The county assessed it at $25,090.

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