603 S William St, Mount Prospect, IL 60056 Property Records

Cook County property record for 603 S William St, Mount Prospect, IL 60056

Property Summary

Property Type	Single Family Home
Details	3 bd · 2.5 ba · 1,586 sqft · built 1956
Lot Size	0.209 acres (9,112 sqft)
Owner	Individual Name on File
Last Sale	$432,500 (Jul 2018)
Tax Bill	$11,054 (2023)
Deeds & Mortgages	Oct 2025 Mortgage Oct 2020 Mortgage + 2 more
Flood Zone	Zone X (minimal risk)
APN	`08-12-411-024`

Property Details

APN / Parcel Number

Primary APN	`08-12-411-024`
Alternative APN	`08-12-411-024-0000`

Interior

Bedrooms	3 Beds
Full Baths	2.5 Baths
Half Baths	1 Half Bath
Total Rooms	6 Rooms
Stories	1 Story
Building Area	1,586 sqft Living Area
1st Floor Area	1,586 sqft
Fireplaces	1 Fireplace
Fireplace	Fireplace

Exterior

Year Built	Built 1956
Effective Year Built	Effective 1957
Architectural Style	Bungalow
Exterior Material	Brick/Stone
Construction Type	Masonry / Concrete Block
Roof Material	Asphalt
Lot Area	9,112 sqft (0.209 acres)
Garage Type	Detached
Parking Spaces	2 Parking Spaces

Utilities, Heating & Cooling

Cooling System	Central
Heating System	HVAC

Location & Zoning

Street Address	603 S WILLIAM ST
City	MOUNT PROSPECT
State	IL
Zip	60056-3956
Property Category	Residential
Property Type	Residential > Single Family > Home
Legal Range	11E
Legal Township	41N
Legal Section	12
Legal Subdivision	PLEASANT HEIGHTS MOUNT PROSPECT
Legal Block	6
Legal Lot Number	20,21
Jurisdiction	COOK IL
Township / Civil Division	ELK GROVE
Census Block Group	3
Census Block	3010
Census Tract	804901

Owner

603 S William St is owned and occupied by an individual who bought it in July 2018.

Source: Cook County records, as of May 27, 2026

Owner of Record	Individual Name on File
Mailing Address	603 S WILLIAM ST, MOUNT PROSPECT, IL 60056-3956
Occupancy	Owner Occupied
Owner Type	Individual

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

Date	Document
Oct 17, 2025	Deed of Trust, Mortgage · FHA Mortgage LOANDEPOT.COM LLC
Oct 29, 2020	Deed of Trust, Mortgage LOANDEPOT.COM LLC
Jul 29, 2019	Deed of Trust, Mortgage LOANDEPOT.COM LLC
Jul 2, 2018	Warranty Deed, Transfer · Conventional with PMI LOANDEPOT.COM LLC

Assessor's Deed Record

Deed Names	Name on Deed
Last Sale	Jul 2, 2018 · Amount on File
Deed Sale	Jul 2, 2018 · Amount on File
Deed Document Number	201833128
Prior Transfer Date	Aug 8, 2012
Prior Transfer Doc	0000039111
Record Updated	Oct 29, 2026

October 2025: Deed of Trust, Mortgage

Document Type	Deed of Trust
Jurisdiction	COOK IL
Property Address	603 S WILLIAM ST, MOUNT PROSPECT, IL 60056-3956
Transaction Type	Mortgage
Record Updated	Nov 5, 2025
Title Company	FIDELITY NATIONAL TITLE

Transferred To (Grantee/Buyer)

Name	Verified Name
Address	603 S WILLIAM ST, MOUNT PROSPECT, IL 60056-3956

Mortgage

Document Number	0029020471
Date	Oct 17, 2025
Instrument	2529020471

Lender

Name	LOANDEPOT.COM LLC
Type	Mortgage Company
Address	IRVINE, CA 92618

Agreement

Type	FHA Mortgage
Amount	Amount on Record
Term	361 Months
Due	Nov 1, 2055

Interest

Rate	6.62%

October 2020: Deed of Trust, Mortgage

Document Type	Deed of Trust
Jurisdiction	COOK IL
Property Address	603 S WILLIAM ST, MOUNT PROSPECT, IL 60056-3956
Document Number	2033349071
Instrument Date	Oct 29, 2020
Transaction Type	Mortgage
Record Updated	Dec 14, 2020
Title Company	FIDELITY NATIONAL TITLE

Transferred To (Grantee/Buyer)

Name	Verified Name
Relationship	Tenants by the Entirety
Address	603 S WILLIAM ST MOUNT PROSPECT IL 600563956, MOUNT PROSPECT, IL 60056-3956

Mortgage

Document Number	2033349071
Date	Nov 30, 2020
Instrument	33349071

Lender

Name	LOANDEPOT.COM LLC
Type	Funding / Finance Company
Address	FOOTHILL RANCH, CA 92610

Agreement

Amount	Amount on Record
Term	360 Months
Due	Nov 29, 2050

Interest

Rate	2.99%

July 2019: Deed of Trust, Mortgage

Document Type	Deed of Trust
Jurisdiction	COOK IL
Property Address	603 S WILLIAM ST, MOUNT PROSPECT, IL 60056-3956
Document Number	1921849088
Instrument Date	Jul 29, 2019
Transaction Type	Mortgage
Record Updated	Aug 14, 2019
Title Company	FIDELITY NATIONAL TITLE

Transferred To (Grantee/Buyer)

Name	Verified Name
Relationship	Tenants by the Entirety
Address	603 S WILLIAM ST MOUNT PROSPECT IL 600563956, MOUNT PROSPECT, IL 60056-3956

Mortgage

Document Number	1921849088
Date	Aug 6, 2019
Instrument	21849088

Lender

Name	LOANDEPOT.COM LLC
Type	Funding / Finance Company
Address	FOOTHILL RANCH, CA 92610

Agreement

Amount	Amount on Record
Term	360 Months
Due	Aug 5, 2049

Interest

Rate	4.12%

July 2018: Warranty Deed, Transfer

Document Type	Warranty Deed
Jurisdiction	COOK IL
Recording Date	Jul 2, 2018
Property Address	603 S WILLIAM ST, MOUNT PROSPECT, IL 60056-3956
Document Number	1818333128
Instrument Date	Jun 21, 2018
Instrument	18333128
Transaction Type	Transfer
Record Updated	Jul 11, 2018
Title Company	ATTORNEY'S TITLE

Transaction

Amount	Amount on Record
Downpayment	Downpayment on Record
Loan-to-Value (LTV)	LTV on Record
Tax	$432.50
Additional	Arm's Length

Transferred From (Grantor/Seller)

Name	Verified Name

Transferred To (Grantee/Buyer)

Name	Verified Name
Relationship	Tenants by the Entirety
Address	603 S WILLIAM ST MOUNT PROSPECT IL 600563956, MOUNT PROSPECT, IL 60056-3956

Mortgage

Document Number	1818333129
Date	Jul 2, 2018
Instrument	18333129

Lender

Name	LOANDEPOT.COM LLC
Type	Funding / Finance Company
Address	FOOTHILL RANCH, CA 92610

Agreement

Type	Conventional with PMI
Amount	Amount on Record
Term	360 Months
Due	Jul 1, 2048

Tax Assessment & Valuation

Source: Cook County assessment roll, as of May 27, 2026

Property Jurisdictions

Type	Name
State	Illinois
County	Cook County
County Subdivision	Elk Grove Township
Municipality	Mount Prospect Village
Secondary School District	Township High School District 214 (09 - 12)
Elementary School District	Mount Prospect School District 57 (PK - 08)

Tax Bill & Assessment History

Year	Tax Bill	Assessed Value	Assessed Market Value
2025		$49,000 Land $10,934 Building $38,066	$490,000 Land $109,340 Building $380,660
2023	$11,054.00 (+4.27%)
2022	$10,601.00 Homeowner's exemption	$43,000 Land $9,112 Building $33,888	$430,000 Land $91,120 Building $338,880

Assessed value and assessed market value are set for property tax purposes, not market price estimates; both are a fraction of this property's market value.

Flood

FEMA maps place 603 S William St in Zone X, an area of minimal flood risk, though there have been 6 flood claims nearby since 1987.

Source: FEMA National Flood Hazard Layer, effective February 11, 2026 · OpenFEMA NFIP redacted claims and policies, as of September 2026

FEMA Flood Zone	Zone X minimal risk
Flood Insurance Requirement	Not required lenders may require it
Community Rating System	Class 6 (20% premium discount)
Nearby Flood Policies	2 in force
Nearby Flood Claims	6 (1987–2007)
Claims Outside the SFHA	2 of 6
Most Recent Claim	Aug 2007 · Severe Storms And Flooding
Claims by Event	Severe Storms & Flooding, Aug 1987 · 3 claims

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

The area around 603 S William St has no burnable land within ember reach, so its wildfire risk is not rated.

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

Wildfire Risk	Not rated no burnable land within ember reach

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 System	MOUNT PROSPECT serves 41,000 people · EPA ID IL0311980
Water Source	Purchased surface water from NORTHWEST SUBURBAN MUNICIPAL JAWA
Last State Inspection	Aug 2025
Lead	2 ppb (2026–2028) action level 15 ppb

Violations Reported to EPA

Water Quality	None last 10 years
Treatment and Procedure	None last 10 years
Monitoring and Reporting	11 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. The service area is an EPA estimate; the actual supplier may differ.

Internet Providers

Source: FCC Broadband Data Collection, based on 671 locations within half a mile, as of December 31, 2025

Provider	Max Down / Up (Mbps)
AT&T Fiber · DSL in parts of the area	5,000 / 5,000
Xfinity Cable	2,000 / 250
Astound Broadband Cable	1,500 / 50
Verizon Fixed Wireless	1,000 / 75

May also be available: T-Mobile.

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