Thames Water average bill (2025/26)
The average Thames Water household water and sewerage bill is £639 a year in 2025/26 (serving London & Thames Valley), up £151 (31%) on 2024/25. That is £36 above the England & Wales average of £603, giving a Gera Water Cost Index of 106. Source: Water UK / Ofwat, published January 2025.
Source: Water UK — Annual average bill changes 2025-2026 (echoed by Ofwat). As of . Updated annually · last updated .
2025/26 average bill
£639
per year (water + sewerage)
Change on 2024/25
+£151
31% (from £488)
Gera Water Cost Index
106
100 = England & Wales average
Thames Water serves London & Thames Valley. Its average bill is £36 above the England & Wales average of £603 (GWCI 106). You cannot switch water company — it is set by your address.
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Pick your water company and household to see how your bill compares to the published company average and the England & Wales average for 2025/26.
Estimated annual water + sewerage bill (Thames Water)
£639
- Company average
- £639/yr
- England & Wales avg
- £603/yr
- Gera Water Cost Index
- 106 / 100
Thames Water’s average bill is £36 above the England & Wales average (GWCI 106).
The company average is the real published 2025/26 figure. The household estimate applies an indicative usage multiplier (a rule of thumb, not a company figure) — your actual bill depends on metered usage, property band, and any social tariff. A metered home often pays less; check your supplier’s charges scheme for an exact figure.
Thames Water water bills — FAQ
How much is the average Thames Water bill in 2025/26?
The average Thames Water household water and sewerage bill is £639 a year in 2025/26, up from £488 in 2024/25 — a rise of £151 (31%). This is the average across Thames Water's household customers in London & Thames Valley; your own bill depends on metered usage, property band, and any social tariff. Source: Water UK / Ofwat.
Why did my Thames Water bill go up?
Thames Water bills rose 31% (£151) from April 2025 following Ofwat's 2024 price review, which approved company investment programmes for 2025–2030. Across England and Wales the average rise was 26% — the steepest since privatisation. Thames Water's rise was above that national average.
Is Thames Water expensive compared to other water companies?
Thames Water's average bill of £639 is £36 above the England & Wales average of £603, a Gera Water Cost Index of 106 (where 100 = the national average). You cannot switch away from Thames Water — your water company is set by where you live in London & Thames Valley. Source: Water UK / Ofwat, 2025/26.
Can I switch away from Thames Water?
No. The household water market in England and Wales is not open to switching, so you cannot leave Thames Water for another supplier — it is fixed by your address. You can lower your bill by getting a water meter if you use less than the rateable-value assumption, checking eligibility for a social tariff such as WaterSure, and fixing leaks.
Lower your London & Thames Valley water bill
You can’t switch away from Thames Water, but a fixed leak or a water-efficient install can cut a metered bill. Book a vetted GeraHome plumber to find leaks or fit water-saving taps, showers and toilets.
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Method & sources
The Gera Water Cost Index (GWCI) re-expresses each company’s published 2025/26 average annual household water + sewerage bill as a ratio to the England & Wales average (£603), indexed so that 100 = the national average. GWCI = round(company average bill ÷ £603 × 100). A GWCI of 120 means the average bill in that company’s area is 20% above the national average; 84 means 16% below. It is computed only from the published figures shown on the page, so anyone can reproduce it. It does not adjust for usage, property band, or social tariffs — it compares published company averages, not individual bills.
Average annual household bills are published by Water UK (the industry body) and echoed by the regulator Ofwat. Reproduced here as public-interest reference figures; per-company numbers cross-verified against multiple independent republications on 2026-06-18. Sources: Water UK — Annual average bill changes 2025-2026 · Ofwat — Average bills 2025/26 press statement. Fetched 2026-06-18. Average bill, not an individual bill — your bill depends on metered usage, property band and any social tariff.