Upgrading to a Dual Flush Toilet for Water Savings in London
Toilet flushing accounts for approximately 30 percent of total household water use in London properties. Upgrading from an older single-flush toilet to a modern dual-flush model is one of the single most effective water-saving measures available to London homeowners and landlords, with a typical payback period of two to five years on a metered supply.
How Much Water Does a Toilet Use in a London Home?
In a typical London household, the toilet is flushed between five and ten times per person per day. An older single-flush toilet with a 9-litre cistern uses 9 litres every flush. In a household of two adults and two children flushing a total of thirty times per day, that amounts to 270 litres of drinking-quality mains water used solely for toilet flushing, or approximately 98,550 litres per year. Thames Water charges metered customers for this water at the same rate as water used for drinking and cooking, making toilet flushing one of the most costly elements of a household water bill.
Modern dual-flush toilets use 6 litres for a full flush and 3 to 4 litres for a half flush. If two-thirds of flushes are half flushes and one-third are full flushes, the average flush volume drops to approximately 4 to 4.5 litres, a reduction of more than 50 percent compared with an older 9-litre single-flush toilet. For the same household flushing thirty times per day, the annual toilet water use drops from 98,550 litres to approximately 49,000 litres, a saving of almost 50,000 litres per year.
Types of Dual Flush Toilet Available for London Properties
There are three main types of dual flush toilet available for installation in London homes. Close-coupled toilets, where the cistern sits directly on top of the pan, are the most common type in UK domestic bathrooms and are available in dual-flush configurations from virtually all major UK bathroom brands including Ideal Standard, Armitage Shanks, RAK Ceramics, and Duravit. Back-to-wall toilets, where the cistern is concealed within a wall-mounted frame, are increasingly popular in modern London flat refurbishments and new-build properties, and all current concealed cistern systems are dual flush as standard. Wall-hung toilets, suspended above the floor on a steel carrier frame with a concealed cistern built into a false wall or duct, are the premium option and are also universally dual flush.
For London properties where the existing toilet is a close-coupled single-flush model, the most cost-effective upgrade is either a full close-coupled dual-flush replacement or an internal cistern mechanism upgrade. The full replacement involves removing the old pan and cistern and fitting a new dual-flush unit, which takes a qualified plumber approximately two to four hours. The cistern mechanism upgrade involves replacing only the internal flushing mechanism within the existing cistern with a dual-flush siphon or valve, which is considerably cheaper but is only possible where the cistern is large enough to accommodate a dual-flush mechanism.
The Cost of a Dual Flush Toilet Installation in London
The cost of a dual-flush toilet installation in a London property depends on whether a full replacement or a mechanism upgrade is required. A full close-coupled dual-flush toilet, including a mid-range ceramic pan and cistern, costs between one hundred and fifty and four hundred pounds for the suite itself. Labour for removal of the old toilet and installation of the new one typically costs between one hundred and fifty and two hundred and fifty pounds in London, bringing the total installed cost to between three hundred and six hundred and fifty pounds.
A cistern mechanism upgrade, where the existing pan is retained and only the internal flushing mechanism is replaced with a dual-flush siphon or push-button valve, costs between thirty and eighty pounds for the parts and approximately one hour of plumber labour at London rates, giving a total cost of between one hundred and one hundred and sixty pounds. The saving in water consumption is similar to a full replacement, but the cistern mechanism upgrade is only suitable where the existing cistern volume is compatible with the new mechanism.
Thames Water Toilet Rebate Schemes and Subsidies
Thames Water periodically offers rebate schemes and free devices to help metered customers reduce toilet water use. In past schemes, Thames Water has offered free dual-flush retrofit kits for installation in existing single-flush toilets, and in some periods has offered financial incentives for full dual-flush toilet replacements. It is worth checking the Thames Water website before committing to a toilet upgrade, as these schemes can reduce the payback period considerably. Prestige Engineers can advise on the current availability of rebate schemes and can ensure that any new toilet installation is registered correctly to qualify for any available incentive.
Other Toilet Water Saving Measures
For properties where a full dual-flush upgrade is not immediately practical, there are several lower-cost interim measures. A save-a-flush bag or Hippo device placed inside the cistern displaces approximately one litre of water per flush and can be obtained free from Thames Water. Checking and repairing a running toilet, where the cistern continues to slowly leak water into the pan after the flush has completed, is essential: a running toilet can waste between 200 and 400 litres per day, equivalent to between twenty and fifty pounds per month on a metered supply.
Prestige Engineers carry out toilet installations and cistern mechanism upgrades across all London boroughs. A plumber can inspect the existing toilet, advise on whether a mechanism upgrade or full replacement is the better option for the specific installation, and carry out the work with minimal disruption to the household. For landlords upgrading multiple properties, a schedule of toilet replacements can be arranged to maximise efficiency and minimise call-out costs.