18, WILLIAM STREET, MUMBLES, SWANSEA, SA3 4LJ - £265,000

Based on the January 2025 Price Paid Data (released on 3rd March 2025), the December 2024 House Price Index (released on 19th February 2025), and the January 2025 Energy Performance of Buildings Data (released on 27th February 2025). Sources

18 WILLIAM STREET is a very small detached house of 64m², built sometime between 1996 and 2002. It was last sold for £265,000 in June 2021, which was around 4% below the average June 2021 detached price in the Swansea local authority area. The most recent EPC inspection was October 2016, where the current energy rating was D, and the potential energy rating was B.

18 WILLIAM STREET Sold Prices

Land registry data shows two sales for 18 WILLIAM STREET since 1^st January 1995. The below table shows the price paid for the two sales, along with the average detached price in the Swansea local authority area for the corresponding sale date. One of the two 18 WILLIAM STREET sales was for below the average price, whilst the other was for above the average price. The average price is sourced from the Office for National Statistics' House Price Index (HPI).

Date	Price	HPI Price	Variation from HPI
2021 29 JUN	£265,000	£275,531	4% below HPI
2016 14 DEC	£270,000	£221,209	22% above HPI

18 WILLIAM STREET Price Paid vs. HPI Average

The below graph shows the average detached house price in the Swansea local authority area over time, sourced from the HPI. The two 18 WILLIAM STREET sales from December 2016 and June 2021 have been plotted on the graph. A line has been extrapolated to show what the value of the property might have been over time, following each sale, had it maintained the same margin above or below the HPI (as a percentage). For example, the December 2016 sale was for 22% above the HPI. So the extrapolation line tracks at 22% above the HPI over time, until the June 2021 sale, where it falls to 4% below the HPI. The line then continues to track at 4% below the HPI.

What might 18 WILLIAM STREET be worth now?

18 WILLIAM STREET might now be worth an estimated £308,245.

This is based on house price inflation of 16.3%, between June 2021 and December 2024, for detached houses, in the Swansea local authority area, as calculated by the Office for National Statistics and published in their UK House Price Index (HPI).

The 16.3% inflationary increase is applied to the most recent sale price for 18 WILLIAM STREET of £265,000 on 29th June 2021. For the value to have increased from £265,000 to £308,245 over the two years and six months to December 2024, the following assumptions must hold true:

• The value of 18 WILLIAM STREET has moved in line with the HPI for detached houses in the Swansea local authority area.
• The June 2021 sale price of £265,000 represented a fair market value for the property.
• The size, condition, and specification of 18 WILLIAM STREET has not materially changed since June 2021.

How Large is 18 WILLIAM STREET?

18 WILLIAM STREET is 64m² according to the EPC inspection conducted in October 2016. This puts it in the smallest 10% of detached houses houses in Swansea, based on EPC data. The below chart shows the distribution of detached houses houses by size in Swansea, and where 18 WILLIAM STREET lies on this distribution: 4% of detached houses houses are smaller than 18 WILLIAM STREET, and 96% of houses are larger. Note that EPC data is not available for all properties in Swansea.

18 WILLIAM STREET: Plot and Title Map

18 WILLIAM STREET sits on a plot of roughly 0.012 of an acre, or 47m². The below map shows the location of 18 WILLIAM STREET, an approximate outline of the building(s), and the indicative extent of the property. The plot extent is a Land Registry INSPIRE Index Polygon, and it is important to note that a title may include more than one polygon, whereas only one polygon is shown on the map (the polygon which intersects with the position of 18 WILLIAM STREET). The full extent of the land contained in any registered title can only be identified from the individual title plan. The maps on this page should not be relied upon to establish the extent of a title.

Where is 18 WILLIAM STREET?

18 WILLIAM STREET is located in MUMBLES, in the SA3 postcode district. The below map shows the position of No. 18 on WILLIAM STREET.