Thames Water's 2026-27 charges scheme sets out a three-block water tariff whose top rate, 686.31 pence per cubic meter, is more than four times the 161.83 pence charged on the first block. The Smart Saver tariff is a two-year trial planned for the 2026-27 charging year.
How the blocks work
The first 50 m³ a year costs 161.83 pence per m³ for water, about 59% of the standard metered rate of 273.46 pence. Use between 51 and 250 m³ costs 323.65 pence. Use above 250 m³ a year, about 685 liters a day for the household, costs 686.31 pence, roughly 2.5 times the standard rate.
Participation is by invitation only. Selected households already have a smart meter, cannot opt out and are billed monthly against their annual block limits divided by 12.
Price needs meters
A tariff based on volume only works where homes are metered. Household meter penetration was 61.7% in 2025-26, and the company's 2024 water resources plan targets 72% by 2030. That plan expects innovative tariffs to save 5.21 Ml/d in 2025–2030, about 3% of a 170.13 Ml/d demand management program, and notes that demand may not respond strongly enough to price for tariffs to have a marked impact.
Affordability pulls the other way. Customers on WaterHelp and WaterSure social tariffs rose to 593,987 in FY 2025/26 from 408,670 a year earlier, and WaterSure caps metered water charges at £372 a year for qualifying customers.
What comes next
Per capita consumption rose to 139.2 liters a day in FY 2025/26, against a national goal of 110 by 2050. The trial results will help decide whether rising blocks extend beyond selected homes.
The report sets out how metering, visits, business programs and drought restrictions performed against plan, and which government measures the plan depends on. The full report, Urban Water Security and Demand Management: Thames Water, is available for USD 499 at https://ourfuturewaterintelligence.com/reports/urban-water-security-and-demand-management-thames-water. For a free overview, read the Thames Water Utility Snapshot at https://ourfuturewaterintelligence.com/utilities/thames-water.