53, WILLIAM STREET, TRETHOMAS, CAERPHILLY, CF83 8FX - £255,000

The information on this page is based on a number of underlying datasets, most of which are updated monthly. We maintain an update schedule which explains which version of each dataset we are currently relying on.

53 WILLIAM STREET is a very small detached house of 81m², built sometime between 1983 and 1990, which could now be worth an estimated £265,353. It was last sold for £255,000 in November 2025, which was around 16% below the average November 2025 detached price in the Caerphilly local authority area. The most recent EPC inspection was June 2025, where the current energy rating was C, and the potential energy rating was B.

53 WILLIAM STREET Sold Prices

Land registry data shows four sales for 53 WILLIAM STREET since 1^st January 1995. The below table shows the price paid for the four sales, along with the average detached price in the Caerphilly local authority area for the corresponding sale date. two of the four 53 WILLIAM STREET sales were for below the average price, and four were 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
2025 12 NOV	£255,000	£304,456	16% below HPI
2005 15 FEB	£173,000	£154,685	12% above HPI
2003 22 AUG	£129,950	£115,053	13% above HPI
2000 8 DEC	£69,000	£78,443	12% below HPI

53 WILLIAM STREET Price Paid vs. HPI Average

The below graph shows the average detached house price in the Caerphilly local authority area over time, sourced from the HPI. The four 53 WILLIAM STREET sales between December 2000 and November 2025 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 February 2005 sale was for 12% above the HPI. So the extrapolation line tracks at 12% above the HPI over time, until the November 2025 sale, where it falls to 16% below the HPI. The line then continues to track at 16% below the HPI.

What might 53 WILLIAM STREET be worth now?

53 WILLIAM STREET might now be worth an estimated £265,353.

This is based on house price inflation of 4.1%, between November 2025 and May 2026, for detached houses, in the Caerphilly local authority area, as calculated by the Office for National Statistics and published in their UK House Price Index (HPI).

The 4.1% inflationary increase is applied to the most recent sale price for 53 WILLIAM STREET of £255,000 on 12th November 2025. For the value to have increased from £255,000 to £265,353 over the one year and six months to May 2026, the following assumptions must hold true:

• The value of 53 WILLIAM STREET has moved in line with the HPI for detached houses in the Caerphilly local authority area.
• The November 2025 sale price of £255,000 represented a fair market value for the property.
• The size, condition, and specification of 53 WILLIAM STREET has not materially changed since November 2025.

How Large is 53 WILLIAM STREET?

53 WILLIAM STREET is 81m² according to the EPC inspection conducted in June 2025. This puts it in the smallest 20% of detached houses houses in Trethomas, based on EPC data. The below chart shows the distribution of detached houses houses by size in Trethomas, and where 53 WILLIAM STREET lies on this distribution: 11% of detached houses houses are smaller than 53 WILLIAM STREET, and 84% of houses are larger. Note that EPC data is not available for all properties in Trethomas.

53 WILLIAM STREET: Plot and Title Map

53 WILLIAM STREET sits on a plot of roughly 0.084 of an acre, or 339m². The below map shows the location of 53 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 53 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 53 WILLIAM STREET?

53 WILLIAM STREET is located in TRETHOMAS, in the CF83 postcode district. The below map shows the position of No. 53 on WILLIAM STREET.