Underdale

An assessment of population growth drivers in Underdale reveals an overall ranking slightly below national averages considering recent, and medium term trends

Based on ABS population updates and AreaSearch validation, the population of Underdale is estimated at around 3,176 as of May 2026. This reflects an increase of 747 people since the 2021 Census, which reported a population of 2,429. The change was inferred from AreaSearch's estimation following examination of the latest ERP data release by the ABS in June 2025 and an additional 34 validated new addresses since the Census date. This level of population equates to a density ratio of 3,113 persons per square kilometer, placing it in the upper quartile relative to national locations assessed by AreaSearch. Underdale's growth of 30.8% since the 2021 census exceeded the state's growth rate of 7.5%. Population growth was primarily driven by overseas migration contributing approximately 89.0% of overall population gains during recent periods.

AreaSearch adopts ABS/Geoscience Australia projections for each SA2 area, as released in 2024 with a base year of 2022. For areas not covered and years post-2032, the SA State Government's Regional/LGA projections by age category are adopted, based on 2021 data released in 2023. Future population dynamics anticipate an increase just below the median of national statistical areas, with the suburb expected to grow by 313 persons to 2041, reflecting a total increase of 9.9% over the 16 years.

Recent residential development output has been above average within Underdale when compared nationally

AreaSearch analysis of ABS building approval numbers in Underdale shows an average of 14 new dwelling approvals per year over the past five financial years, totalling an estimated 71 homes. As of FY-26, 11 approvals have been recorded. On average, 2.9 people move to the area per new home constructed annually between FY-21 and FY-25, indicating healthy demand for property values. The average construction cost value of new homes is $465,000, targeting the premium market segment with higher-end properties.

In this financial year, $9.5 million in commercial approvals have been registered, showing steady commercial investment activity. Compared to Greater Adelaide, Underdale records about three-quarters the building activity per person and ranks among the 81st percentile nationally for building activity, though recent years have seen accelerating growth. The new building activity mix is 67.0% detached houses and 33.0% medium and high-density housing, with a growing variety of townhouses and apartments catering to different price points.

With around 133 people per dwelling approval, Underdale exhibits characteristics of a growth area. According to the latest AreaSearch quarterly estimate, Underdale is projected to add 313 residents by 2041. At current development rates, new housing supply should comfortably meet demand, creating favourable conditions for buyers and potentially supporting population growth beyond current projections.

Underdale has emerging levels of nearby infrastructure activity, ranking in the 21stth percentile nationally

Changes to local infrastructure significantly influence an area's performance. AreaSearch has identified one major project likely impacting this area: Henley Beach Road Visioning Project; Harbour Town Premium Outlets Adelaide Expansion; New Women's and Children's Hospital; North South Corridor. Most relevant projects are listed below.

Professional plan users can use the search below to filter and access additional projects.

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Underdale ranks among the top 25% of areas assessed nationally for overall employment performance

Underdale has a highly educated workforce with significant representation in essential services sectors. The unemployment rate was 3.0% as of December 2025, lower than Greater Adelaide's 3.8%. Employment growth over the past year was estimated at 11.2%, based on AreaSearch aggregation of statistical area data.

As of December 2025, 1,929 residents were employed, with an unemployment rate 0.8% below Greater Adelaide's and workforce participation at 73.5%. Census responses indicated that only 11.3% of residents worked from home, though Covid-19 lockdown impacts should be considered. The dominant employment sectors in Underdale include health care & social assistance, education & training, and retail trade. The area shows strong specialization in finance & insurance, with an employment share 1.4 times the regional level.

Conversely, manufacturing is under-represented, at 5.6% compared to Greater Adelaide's 7.0%. The ratio of workers to residents was 0.7 as at the Census, indicating a higher-than-average level of local employment opportunities. During the year to December 2025, employment levels in Underdale increased by 11.2%, and labour force grew by 10.5%, resulting in an unemployment rate decrease of 0.7 percentage points. This contrasts with Greater Adelaide, where employment rose by 4.2%, the labour force grew by 3.9%, and unemployment fell by 0.3 percentage points. National employment forecasts from Jobs and Skills Australia, released in May-25, project national employment growth at 6.6% over five years and 13.7% over ten years. Applying these projections to Underdale's employment mix suggests local employment should increase by 6.7% over five years and 14.0% over ten years, though these are simple weighting extrapolations for illustrative purposes and do not account for localized population projections.

The area's income profile falls below national averages based on AreaSearch analysis

The suburb of Underdale has an average national income level according to the latest Australian Taxation Office (ATO) data aggregated by AreaSearch for the financial year 2023. The median income among taxpayers in Underdale is $53,661, with an average income of $67,028. This compares to Greater Adelaide's figures of $54,808 and $66,852 respectively. Based on Wage Price Index growth of 10.17% since the financial year 2023, current estimates for Underdale would be approximately $59,118 (median) and $73,845 (average) as of March 2026. According to census data, household, family, and personal incomes in Underdale rank modestly, between the 40th and 55th percentiles. Income distribution shows that the $1,500 - $2,999 bracket dominates with 30.3% of residents (962 people), similar to regional levels where 31.8% occupy this bracket. Housing affordability pressures are severe in Underdale, with only 84.4% of income remaining after housing costs, ranking at the 41st percentile. The suburb's Socio-Economic Indexes for Areas (SEIFA) income ranking places it in the fifth decile.

Underdale displays a diverse mix of dwelling types, with a higher proportion of rental properties than the broader region

Underdale's dwelling structure, as per the latest Census, consisted of 63.6% houses and 36.5% other dwellings (semi-detached, apartments, 'other' dwellings). In comparison, Adelaide metro had 75.2% houses and 24.9% other dwellings. Home ownership in Underdale was 31.1%, similar to Adelaide metro's figure, with the rest being mortgaged (31.1%) or rented (37.9%). The median monthly mortgage repayment in Underdale was $1,786, higher than Adelaide metro's average of $1,562. Median weekly rent in Underdale was $310, compared to Adelaide metro's $320. Nationally, Underdale's mortgage repayments were lower than the Australian average of $1,863, while rents were substantially below the national figure of $375.

Underdale features high concentrations of group households and lone person households, with a lower-than-average median household size

Family households account for 62.4% of all households, including 28.2% couples with children, 24.2% couples without children, and 8.7% single parent families. Non-family households constitute the remaining 37.6%, with lone person households at 31.9% and group households comprising 5.4%. The median household size is 2.3 people, which is smaller than the Greater Adelaide average of 2.5.

Educational attainment in Underdale aligns closely with national averages, showing typical qualification patterns and performance metrics

The area's educational profile is notable regionally with university qualification rates at 35.6%, exceeding South Australia's average of 25.7% and Greater Adelaide's rate of 28.9%. Bachelor degrees are the most common at 23.9%, followed by postgraduate qualifications (9.2%) and graduate diplomas (2.5%). Vocational credentials are also prominent, with 28.9% of residents aged 15+ holding such qualifications, including advanced diplomas (10.7%) and certificates (18.2%).

Educational participation is high, with 26.6% of residents currently enrolled in formal education, comprising 8.1% in primary, 6.5% in tertiary, and 5.6% in secondary education.

Transport servicing is high compared to other areas nationally based on assessment of service frequency, route connectivity and accessibility

Underdale has 14 active public transport stops operating within its boundaries. These stops serve a mix of bus routes, totalling 24 individual routes that facilitate 1,682 weekly passenger trips combined. The area's transport accessibility is rated as excellent, with residents typically located just 153 meters from their nearest transport stop. Being predominantly residential, most Underdale residents commute outward. Cars remain the primary mode of transportation for 81% of residents, while buses are used by 9%. On average, there are 1.3 vehicles per dwelling in the area.

According to the 2021 Census, a relatively low 11.3% of Underdale residents work from home, which may be influenced by COVID-19 conditions. The service frequency across all routes averages 240 trips per day, equating to approximately 120 weekly trips per individual stop.

Underdale's residents are extremely healthy with both young and old age cohorts seeing low prevalence of common health conditions

Analysis of health metrics shows strong performance throughout Underdale.

AreaSearch's assessment indicates low prevalence of common health conditions in both young and old age cohorts. The rate of private health cover is approximately 53% of the total population (~1,698 people), leading that of the average SA2 area. The most common medical conditions are mental health issues and asthma, impacting 6.6 and 6.4% of residents respectively. 74.1% of residents declared themselves completely clear of medical ailments, compared to 67.9% across Greater Adelaide. Working-age residents have low chronic condition prevalence. The area has 18.5% of residents aged 65 and over (587 people). Health outcomes among seniors are particularly strong, with national rankings higher than the general population.

Underdale was found to be more culturally diverse than the vast majority of local markets in Australia, upon assessment of a range of language and cultural background related metrics

Underdale has a high level of cultural diversity, with 33.6% of its population born overseas and 35.5% speaking a language other than English at home. Christianity is the predominant religion in Underdale, making up 49.6% of the population. Notably, the category 'Other' comprises 3.9% of Underdale's population, which is higher than the regional average of 1.8%.

Regarding ancestry, the top three represented groups are English (19.1%), Australian (18.2%), and Other (12.3%). Some ethnic groups have notable representation in Underdale compared to Greater Adelaide: Greek (6.6% vs 2.0%), Italian (10.9% vs 5.2%), and Indian (4.9% vs 2.3%).

Underdale's population aligns closely with national norms in age terms

Underdale's median age is 38, nearly matching Greater Adelaide's figure of 39 and Australia's median age of 38. Compared to Greater Adelaide's average, Underdale has an over-representation of the 25-34 cohort at 16.9%, while the 5-14 year-olds are under-represented at 9.9%. Between 2021 and present, the 65-74 age group has increased from 8.9% to 9.9% of the population. Conversely, the 55-64 cohort has decreased from 13.3% to 11.6%. By 2041, demographic modeling suggests significant changes in Underdale's age profile. The 45-54 age cohort is projected to grow by 80 people (21%), from 374 to 455. Conversely, the 0-4 age group is projected to decrease by 5 residents.