Castlecrag vs Seaforth, true annual running costs compared 2026
Last updated July 2026 · council rates current NSW schedules, ATO 91c/km, Opal & Translink fares, AER electricity benchmarks
Castlecrag (Willoughby rates (OLG) and Seaforth (Northern Beaches rates (OLG) attract comparison from buyers considering suburbs across different council areas at similar distances from Sydney CBD (7.8 km and 8.6 km).
The two sit within $3 a year of each other to run, so running cost is a minor factor here. The decision comes down to schools, risk and lifestyle, all in the free report.
Over 10 years these two cost about the same to run.
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Seaforth
Annual cost breakdown
| Category | Castlecrag | Seaforth | Difference |
|---|---|---|---|
| Council rates Official, 2026-27 | $1,341 | $1,766 | -$425 |
| Water & sewerage Official, 2026-27 | $1,548 | $1,548 | - |
| Commute (driving) Modelled, 2026-27 | $2,460 | $2,682 | -$222 |
| Commute (public transport) Modelled, 2026-27 | $1,920 | $1,920 | - |
| Home insurance Estimated | $2,150 | $1,500 | +$650 |
| Body corporate (unit) Estimated | $2,600 | $2,600 | - |
| Total (driving) | $7,499 | $7,496 | +$3 |
| Total (public transport) | $6,959 | $6,734 | +$225 |
Totals exclude electricity, estimated separately below. Green = cheaper. Commute: ATO 91c/km, 220 working days. Insurance estimated from ACCC premium rates; actual premiums vary. Council rates: average residential rate (NSW, IPART-uplifted).
| Dwelling | Castlecrag | Seaforth | Difference |
|---|---|---|---|
| House | $2,342 | $2,342 | - |
| Unit | $1,909 | $1,909 | - |
Estimated from AER residential benchmarks for each suburb's climate zone at 2026-27 regulated prices for each suburb's electricity network, including supply charge (AER Default Market Offer caps, or the QCA price in regional Queensland; unit ≈ 75% of a house). Get the free report for a breakdown by your exact number of occupants.
Cost breakdown chart
Annual cost breakdown, Castlecrag vs Seaforth (2026-27)
What the numbers show
Castlecrag and Seaforth cost within $3 of each other annually by car. Over ten years with 3% annual growth the gap reaches roughly $35, making running cost a minor factor in the decision.
The biggest single gap is home insurance at $650 per year.
On public transport the gap is $225 per year, $6,959 from Castlecrag versus $6,734 from Seaforth.
Where the difference actually comes from
- Council rates favours Castlecrag by $425 a year, $1,341 against $1,766.
- Water and sewerage is identical at $1,548 a year.
- Driving commute favours Castlecrag by $222 a year, $2,460 against $2,682.
- Building insurance favours Seaforth by $650 a year, $1,500 against $2,150.
They sit in different council areas, so the rates line is set by two different councils. For NSW that figure is the average residential rate reported to the Office of Local Government, uplifted by that council's IPART rate peg.
10-year cumulative cost projection
| Year | Castlecrag cumulative | Seaforth cumulative | Difference |
|---|---|---|---|
| Year 1 | $7,499 | $7,496 | $3 |
| Year 3 | $23,179 | $23,169 | $10 |
| Year 5 | $39,813 | $39,797 | $16 |
| Year 10 | $85,968 | $85,933 | $35 |
Assumes 3% annual cost growth. Excludes purchase price, mortgage, and personal expenses.
Frequently asked questions
Is Castlecrag or Seaforth cheaper to live in?
Seaforth is cheaper to run by car at $7,496 per year versus $7,499 for Castlecrag, a difference of $3 annually. Figures cover council rates, water, commute (ATO 91c/km), and home insurance. Source: SuburbCost 2026 data.
What are council rates in Castlecrag and Seaforth?
Annual council rates for a house are $1,341 in Castlecrag (Willoughby rates (OLG) and $1,766 in Seaforth (Northern Beaches rates (OLG). Water and sewerage adds $1,548 in Castlecrag and $1,548 in Seaforth. Both figures are the average residential rate reported to the Office of Local Government, uplifted by each council's IPART rate peg.
How does the commute cost compare between Castlecrag and Seaforth?
Annual driving commute costs are $2,460 from Castlecrag and $2,682 from Seaforth to Sydney CBD (ATO 91c/km). Public transport costs $1,920 from Castlecrag and $1,920 from Seaforth.
What is the 10-year cost difference between Castlecrag and Seaforth?
At 3% annual cost growth, Castlecrag costs a cumulative $85,968 and Seaforth costs $85,933 over 10 years by car. The cumulative difference is $35 in favour of Seaforth. Excludes purchase price, mortgage, and personal expenses.
Which of Castlecrag and Seaforth suits you better?
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Sources: Willoughby rates (OLG and Northern Beaches rates (OLG rate data, water utility pricing (QLD: Queensland Urban Utilities / Unitywater; NSW: Sydney Water / Hunter Water), ATO 91c/km, and SuburbCost insurance estimates from ACCC premium rates. Data updated July 2026.