Thirlmere
Spread across 32.83 km2 at just 151.9 residents per km2, Thirlmere is one of the more land-rich pockets of the Wollondilly fringe, and the housing reflects it: 90.2% of dwellings are separate houses and 53.3% carry four or more bedrooms. The median house price sits at $907,500, supported by household incomes in the 59.8th percentile nationally. The median age of 38 runs 2.0 years below the national figure, and the suburb skews family-heavy, with couples raising children (1,632 families) outnumbering childless couples. University qualifications reach only 18.3%, which is 11.8 points below national, pointing to a trades and services workforce rather than a professional one.
Population
4,986
Median Age
38.0
Household IncomeiMedian weekly household income (ABS Census)
$1,708/wk
DAs (12 months)iDevelopment Applications lodged in the past year
139
Median House
$908K
2024-2025 (PSI derived)
At a $907,500 median, Thirlmere buys far more space than comparable Sydney-metro prices, because 90.2% of stock is detached housing and 53.3% of dwellings have four or more bedrooms, against just 13.0% with two. Prices have been flat to slightly soft, easing 0.5% from $910,000 in 2024 to $905,000 in 2025, so buyers are not chasing a rising market. The trade-off is leverage: monthly mortgage repayments average $2,300 and the mortgage-to-income ratio is 31.1%, just past the 30% stress threshold, which flags the area as mortgage-stretched despite household income in the 59.8th percentile. With 43.4% of households carrying a mortgage versus 31.9% owning outright, this is a working-family ownership market rather than a cashed-up one.
For Buyers
At a $907,500 median, Thirlmere buys far more space than comparable Sydney-metro prices, because 90.2% of stock is detached housing and 53.3% of dwellings have four or more bedrooms, against just 13.0% with two. Prices have been flat to slightly soft, easing 0.5% from $910,000 in 2024 to $905,000 in 2025, so buyers are not chasing a rising market. The trade-off is leverage: monthly mortgage repayments average $2,300 and the mortgage-to-income ratio is 31.1%, just past the 30% stress threshold, which flags the area as mortgage-stretched despite household income in the 59.8th percentile. With 43.4% of households carrying a mortgage versus 31.9% owning outright, this is a working-family ownership market rather than a cashed-up one.
For Investors
Renters make up 24.7% of households, a smaller pool than inner-city markets, and weekly rent of $420 against the $907,500 median implies a gross yield near 2.4%, modest but typical for detached outer-Sydney stock. The 6.1% vacancy rate is higher than a tight rental market would show, so tenant demand is steady rather than scarce. Development is active, with 129 applications lodged in the past 12 months, many for new dwelling construction, which signals gradual greenfield-style supply rather than density. With rent-to-income at 24.6%, tenants have headroom, but the flat price trend (down 0.5% year on year) means the investment case leans on long-run capital growth and rental cashflow rather than near-term appreciation.
Development Activity
Total DAs
719
Last 12 Months
139
YoY ChangeiYear-over-year change in DA lodgements
+47.9%
Avg DA CostiAverage estimated cost per DA in the past year
N/A
Monthly DA Lodgements
DA Categories
Schools in Thirlmere iICSEA: school advantage index. 1000 = national avg, higher = more advantaged
Thirlmere Public School
K-6 · 401 students
Demographics
The median age of 38 is 2.0 years below national, and the family profile is pronounced: 1,632 couples with children outnumber the 1,172 couples without, who make up 28.7% of families. Only 11.2% of residents were born overseas, which is 10.4 points below the national figure, and ancestry is heavily Anglo, led by English (2,008), Irish (510) and Scottish (460). Non-English languages are negligible, with Arabic (31) and Greek (15) the largest. University qualifications at 18.3% sit 11.8 points below national, consistent with a workforce weighted to trades and services. Average household size is 2.7, which is 0.2 above national, reflecting the larger family homes that dominate the dwelling stock.
Age Distribution
Bedrooms
Dwelling Structure
90.2%
Houses
9.1%
Townhouse
0.4%
Apartment
Tenure
Tenure leans toward leveraged ownership: 43.4% of households hold a mortgage, 31.9% own outright and 24.7% rent. Mortgage holders outnumbering outright owners marks this as a buying-and-paying-down market rather than one of established, debt-free wealth. The stock is overwhelmingly detached at 90.2%, with semi-detached at 9.1% and apartments effectively absent at 0.4%, so larger homes drive the profile: 53.3% have four-plus bedrooms and 29.7% have three. The median house price eased from $910,000 in 2024 to $905,000 in 2025, a 0.5% dip, while monthly repayments of $2,300 push the mortgage-to-income ratio to 31.1%, above the stress threshold. Rent-to-income is more comfortable at 24.6%, a gap that shows ownership costs bite harder than renting here.
Median House Price Trend
Source: State Valuer-General
Mortgage / mo
$2,300
Rent / wk
$420
HH Size
2.7
Personal Income / wk
$782
Vacancy Ratei% of dwellings unoccupied on Census night (ABS 2021)
6.1%
Unoccupied
114
Rent / IncomeiMedian rent as % of household income. Over 30% = housing stress
24.6%
Mortgage / IncomeiMedian mortgage as % of household income. Over 30% = housing stress
31.1% stressed
Community Profile
Languages Spoken at Home
Ancestry
Household Composition
28.7%
Couples, no children
4,084
Total families
Economy & Employment
The workforce is concentrated in hands-on sectors: Construction leads at 17.3% (258 workers), Healthcare follows at 16.6% (248) and Education at 11.8% (176), with Manufacturing at 8.6% and Public Admin at 7.8%. By occupation, Professionals (334), Clerical and Admin (291) and Managers (288) are the largest groups, a spread that fits the below-average 18.3% university rate, which sits 11.8 points under national. Unemployment is low at 3.8% and the full-time employment rate is 64.8%. Participation reads 52.3%, held down by 1,356 residents not in the labour force, partly reflecting families with a non-working parent. The construction-heavy mix lines up with the 129 development applications lodged locally over 12 months, a sign that building work is both a local industry and a local activity.
Socio-Economic Indexes (SEIFA)iABS index ranking suburbs from 1 (most disadvantaged) to 10 (most advantaged)
Full-time
64.8%
Part-time
31.4%
Participation
52.3%
Employed
2,022
Occupations
Top Industries
University
18.3%
Postgraduate
4.2%
Born Overseas
11.2%
Dwellings
1,757
Transport to Work
Thirlmere is firmly car-dependent: 91.5% of residents drive to work, far above the national norm, while public transport carries just 0.3% and 1.9% walk or cycle, a pattern set by the low 151.9 residents per km2 density and 32.83 km2 of semi-rural land. No schools are recorded inside the suburb boundary in this dataset, so families rely on institutions in neighbouring towns, a practical trade-off for the spacious, large-lot living that 90.2% detached housing provides. Community engagement is present, with volunteering at 12.4%, and 6.5% of residents (303 people) need daily assistance. Crime statistics are not available for Thirlmere in this dataset, so safety cannot be quantified, but the settled profile, with 74.3% of residents staying put, is consistent with a stable residential area.
Drive
91.5%
Public Transport
0.3%
Walk / Cycle
1.9%
Work from Home
N/A
National Ranking iPercentile rank among ~15,000 AU suburbs. 90% = higher than 90% of suburbs
How Thirlmere compares to ~15,000 Australian suburbs
Frequently Asked Questions
Is Thirlmere a good suburb to live in?
Thirlmere suits families wanting space: 90.2% of homes are detached and 53.3% have four or more bedrooms, with a median age of 38, which is 2.0 years below national. The trade-offs are heavy car reliance (91.5% drive) and a mortgage-to-income ratio of 31.1%, just above the stress threshold.
What is the median house price in Thirlmere?
The median house price is $907,500. Prices were broadly flat over the year, easing 0.5% from $910,000 in 2024 to $905,000 in 2025. Weekly rent averages $420 and monthly mortgage repayments run about $2,300, giving a mortgage-to-income ratio of 31.1%.
What schools are in Thirlmere?
No schools are recorded inside the Thirlmere boundary in this dataset, so families rely on schools in neighbouring towns. The suburb is family-heavy, with 1,632 couples raising children and a median age of 38, which is 2.0 years below the national figure.
Is Thirlmere safe?
Detailed crime statistics are not available for Thirlmere in this dataset. As an indirect signal, residential stability is high, with 74.3% of residents staying put and turnover at just 25.7%, and only 6.5% of the 4,986 residents need daily assistance, both consistent with a settled residential area.
Is Thirlmere good for property investment?
Weekly rent of $420 against the $907,500 median gives a gross yield near 2.4%, modest for detached stock, and the 6.1% vacancy rate shows steady rather than scarce demand. With prices down 0.5% year on year, returns lean on long-run capital growth more than yield.
How is Thirlmere's population changing?
Thirlmere has 4,986 residents at a low density of 151.9 per km2, with room to grow across its 32.83 km2. Growth is organic and family-driven: 74.3% of residents stayed put and the median age of 38 sits 2.0 years below national, pointing to settled household formation rather than churn.
How much development is happening in Thirlmere?
There were 129 development applications lodged in the past 12 months, many for new dwelling construction rather than alterations alone. This fits a land-rich suburb at 151.9 residents per km2 where 90.2% of housing is detached, with Construction the top local industry at 17.3% of workers.
How to read these comparisons
Phrases like "above the national average" reference the unweighted median across Australian suburbs with more than 1,000 residents, not population-weighted national figures. Suburb-level medians are more useful for ranking suburbs against each other; ABS census headlines are population-weighted (so dominated by Sydney and Melbourne) and can read very differently.
Current baseline (refreshed 2026-05-10): median age 40, university-educated 30.1%, born overseas 21.6%, average household size 2.5 people.
Data sources: ABS 2021 Census (demographics, income, tenure), state Valuer-General (house prices), Department of Jobs SALM (unemployment), ACARA (school ICSEA), state Crime Statistics agencies (offences), council DA portals (development applications). Population forecasts use a Hamilton-Perry cohort model calibrated to ABS ERP.
Explore Thirlmere on the Map
View parcels, zoning overlays, DA applications, schools and more.
Open Interactive Map