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Grundy County, Illinois

Single-family vs. condo trends, market pressure signals, and 5-year price history. Source: Redfin.

Median Sale Price
$323,300
+34.7% YoY
Active Inventory
157
Days on Market
50 days
Price Drops
18.5%

Single-Family vs. Condo

Source: Redfin (property-type breakdown)
Single-Family Median
$343,500
-3.5% YoY
Condo / Co-op Median
$259,000
+12.1% YoY
SFR vs. Condo YoY Gap
-15.6%
condos outperforming SFR
DOM: SFR vs. Condo
53d / 33d
SFR / Condo

Buyer vs. Seller Market Indicators

Latest month — Redfin
Months of Supply
2.4 mo
Seller market

Inventory ÷ monthly sales. Below 3 = strong seller market; 3-6 balanced; above 6 = buyer market.

Sale-to-List Ratio
99.2%
At asking

Median closing price ÷ original list price. Above 100% = homes routinely closing above asking.

% Sold Above List
39%
Mixed

Share of closed sales priced above asking. The single cleanest read on bidder competition.

What does your sqft target cost in Grundy County, Illinois?

$193/sqft median (Redfin)
+$0 adj
+$0 adj
optional
Estimated price
$385,927
Above median (+19% vs median)
Region median
$323,300
all homes
Price-tier reverse lookup — what sqft does each price band buy?
$600,000
≈ 3,109 sqft
$1,200,000
≈ 6,219 sqft
$2,000,000
≈ 10,365 sqft
$5,000,000
≈ 25,912 sqft

Estimate = (median $/sqft × your sqft) + bed/bath/lot adjustments. Bed and bath adjustments use Appraisal Institute / Fannie Mae standard rules of thumb (~$15K/extra bedroom, ~$20K/extra bathroom vs. a 3bd/2ba baseline; half-bath = half adj). Lot premium is a $1.50/sqft heuristic beyond a 6,000 sqft baseline — accuracy varies sharply by urban infill vs. acreage market. Quality, condition, year built, and HOA are not modeled here. For a deeper county-level hedonic AVM, see AVM Lite.

Rent + invest vs. buy + own — backtested

15-yr rolling history · S&P 500
Property type:
Upfront capital committed (both paths): $74K = 20% down + 3% closing on a $323K home
BUY + OWN
Median ending wealth $284K $173K real
Net gain on $74K upfront: $210K
Range: $284K → $284K
Wealth = home value (appreciated at 3%/yr) − remaining mortgage − 6% selling cost. Gain = wealth − upfront. Leveraged appreciation on full $323K asset comes from the 20% down.
RENT + INVEST
Median ending portfolio $611K $412K real
Net gain on $201K contributed: $410K
Range: $282K → $1.64M
Same upfront cash + each year's (own − rent) surplus invested in S&P 500 at actual annual returns. Median renter contributed $201K total.
Median wealth delta: $327K in favor of RENT + INVEST
What if you'd started in a recent year? (most-recent 15yr window: 2011–2025)
WindowBuy wealthBuy gainRent wealthRent gainWealth delta
2011–2025$284K$210K$913K$712K$629K rent
2010–2024$284K$210K$933K$732K$649K rent
2009–2023$284K$210K$901K$700K$617K rent
2008–2022$284K$210K$604K$403K$320K rent
2007–2021$284K$210K$780K$579K$496K rent
2006–2020$284K$210K$669K$468K$385K rent
2005–2019$284K$210K$599K$398K$315K rent
2004–2018$284K$210K$494K$293K$210K rent

Educational tool, not investment or real-estate advice. Past performance does not guarantee future results. Backtests use actual annual total returns including dividends from S&P 500 (Damodaran (NYU Stern) annual total return (with dividends), 1957-present.).

Buyer model: 30-yr fixed mortgage, P&I + property tax + insurance + maintenance (1% of value/yr) + HOA. Selling cost = 6%. Investor model: down payment + annual cashflow surplus invested in the chosen index at that calendar year's actual return.

Tax model: pre-tax comparison. Toggle "after-tax mode" to apply MID, SALT, LTCG, and the Sec 121 capital-gains exclusion.

This calculator does not adjust for: PMI (assumed 20%+ down), differential transaction costs by state, lifestyle factors (commute, schools, kids), illiquidity / forced-sale risk, or insurance availability constraints (e.g., FL/CA wildfire). Consult a fiduciary advisor and tax professional before acting on any of this.

Market Pressure Signals

Derived from Redfin trend
Inventory vs. Long-Term Avg
+21.1%
surplus — buyer leverage
DOM vs. 24-Mo Avg
+2.1%
currently 50 days
Long-Term Avg Inventory
130
Long-Term Avg DOM
49 days

Mortgage & Price Stress

State HPI + national delinquency
State HPI YoY
+5.8%
positive — appreciating
State HPI vs. Peak
0.0%
at or near peak peak 2026-01-01
National Mortgage Delinquency
1.89%
benchmark — 2026-01-01 county-grain delinquency requires paid data

State-grain HPI YoY + drawdown from peak is the cleanest free price-stress proxy. The national delinquency rate gives the macro mortgage-stress backdrop. True county-level mortgage delinquency lives in paid datasets (MBA NDS, CoreLogic LP).

Value Ratios

Median home price ÷ county median income
Value / Income
3.5×
fair value
Median Household Income
$93,060
Census ACS B19013

Historically affordable markets sit at 3–4× income; over 5× is stretched, over 6× is severely overvalued. Lower ratios point to bargain opportunities.

Housing Stock & Owners

Census ACS 5-year (B19013, B01003, B25002, B25003, B25034, B25007)
Population
52,920
total residents
Total Housing Units
21,324
all units, occupied + vacant
Vacancy Rate
3.8%
tight
Homeownership Rate
75.8%
of occupied units owner-occupied
Boomer Owners (65+)
19.7%
of homeowner households
Millennial / Gen-X Owners (35-54)
10.0%
of homeowner households
Pre-1949 Housing Stock
15.2%
structures built before 1949

When boomer-owner share is high, expect more inventory hitting the market over the next decade as homes transition. High vacancy + high old-stock often signals deferred-maintenance markets where buyers can negotiate.

Net Migration (IRS Tax Returns)

IRS Statistics of Income — Migration Data
Net Migration
+565
gaining people (2022–2023)
Inbound Returns
1,236
2,165 people moved in
Outbound Returns
991
1,600 people moved out
Net Returns
+245
household-filer basis

Top 5 Origins (where movers came from)

  1. Will, Illinois — 710 returns
  2. Cook, Illinois — 150 returns
  3. LaSalle, Illinois — 95 returns
  4. Kendall, Illinois — 86 returns
  5. DuPage, Illinois — 68 returns

Top 5 Destinations (where movers went)

  1. Will, Illinois — 502 returns
  2. LaSalle, Illinois — 138 returns
  3. Cook, Illinois — 124 returns
  4. Livingston, Illinois — 73 returns
  5. Kendall, Illinois — 62 returns

IRS Statistics of Income tracks county-to-county migration via tax-return change-of-address. Net migration uses the exemption count (a proxy for people, including dependents). True net flow can lag by 1–2 years vs. real-time movements.

Who's Moving In (Census ACS)

Source: Census ACS B07001 (5-year)
Inbound Movers (1 yr)
2,886
5.49% of pop. — moved here from outside the county
From Other States
560
1.07% of pop. — interstate inbound
From Abroad
3
moved into the county from outside the U.S.
Same House 1 Year Ago
91%
stable residents

Census ACS asks where people lived 1 year ago, so this counts inbound movers but does not show outbound — true net migration would require IRS SOI parsing.

Trends

Up to 5 years of monthly data

Median Sale Price

Trailing 12 months

Active Inventory

Trailing 12 months

Days on Market

Trailing 12 months

Looking for state-level data? See Illinois statewide stats →

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