The Water Efficiency Label Scheme (WELS) provides a standardised rating system for water-using plumbing fixtures sold in the UK and Europe, allowing consumers to compare the water efficiency of taps, showers, toilets, and other fittings before purchase. This guide explains how WELS ratings work, what the labels mean, and how to use efficiency ratings when selecting plumbing fixtures for a London property.
What Is the Water Efficiency Label Scheme?
The Water Efficiency Label (WEL) scheme, developed by the European Water Label and adopted for use in the UK and across Europe, provides a voluntary but increasingly widely adopted labelling system that rates the water consumption of plumbing products on a scale from A to G, with A representing the highest efficiency and G the lowest. The scheme covers taps, showers, toilets, urinals, and some other water-using fixtures, and the labels are designed to allow consumers, architects, and specifiers to make informed purchasing decisions based on comparable consumption data.
In the UK, the scheme is overseen by the Water Efficiency Label organisation, which works in conjunction with the Water Regulations Advisory Scheme (WRAS) and with the major trade bodies including the Bathroom Manufacturers Association (BMA) and the Heating and Hotwater Industry Council (HHIC). Although the Water Efficiency Label is voluntary, an increasing number of UK manufacturers and importers register their products and display the label, particularly at the higher-efficiency end of the market where it serves as a selling point.
How Tap Efficiency Is Rated Under WELS
Taps are rated under the Water Efficiency Label based on their maximum flow rate in litres per minute at a reference pressure of 3 bar. An A-rated tap delivers 6 litres per minute or less at 3 bar, while a G-rated tap delivers more than 12 litres per minute. The label also distinguishes between pressure-compensating taps, which maintain a consistent flow rate across a range of supply pressures, and non-compensating taps, which deliver more water at higher pressures.
For London homeowners and landlords selecting taps for a property renovation or new installation, choosing A or B-rated taps rather than D, E, or F-rated products of similar appearance and price can significantly reduce annual water consumption with no impact on the user experience. Most major UK bathroom and kitchen tap manufacturers now offer A-rated options at comparable prices to standard products, and the difference in purchase price between an A-rated and a D-rated tap of similar quality is frequently negligible.
Toilet Flush Ratings and the Flush Volume Standard
Toilets are assessed under the Water Efficiency Label based on the full flush volume and, for dual-flush models, the half flush volume. The UK Water Supply (Water Fittings) Regulations 1999 set a maximum full flush volume of 6 litres for new toilet installations, meaning that any toilet installed after 1999 in a new build or renovation project must flush with no more than 6 litres. However, there is no minimum flush volume, and some high-efficiency models designed for commercial and sustainability-focused applications use as little as 3 to 4 litres for a full flush.
Under the Water Efficiency Label, toilets are rated from A to G based on their average flush volume across a standardised mix of full and half flushes for dual-flush models. An A-rated toilet achieves an average flush volume of 3 litres or less, while current standard close-coupled dual-flush toilets typically achieve ratings of B or C with average flush volumes of 3 to 4.5 litres. For London developers and landlords specifying new toilets in rental properties, selecting A or B-rated models is consistent with meeting the Part G water consumption target under the Building Regulations, which requires that new dwellings have a calculated water consumption of no more than 125 litres per person per day.
Shower Ratings Under the Water Efficiency Label
Shower products are rated under the Water Efficiency Label based on their nominal flow rate in litres per minute at the reference test pressure. An A-rated shower delivers 6 litres per minute or less, a B-rated shower delivers 6 to 8 litres per minute, and the ratings continue up to G for products delivering more than 14 litres per minute. The label also indicates whether the product is an aerating type that mixes air into the water stream or a non-aerating type.
Power showers, which use a pump to boost the flow rate for use with low-pressure gravity-fed hot water systems, typically carry D or E ratings reflecting their high flow rates of 12 to 20 litres per minute. While power showers are valued for their perceived comfort and rinsing effectiveness, they are among the most water-intensive plumbing products in common domestic use, and London households with power showers on metered supplies can make significant savings by replacing them with a lower-flow thermostatic shower valve and an A or B-rated showerhead, provided that the water pressure at the property is sufficient for the replacement product.
Using Water Efficiency Ratings in London Renovation Projects
For London homeowners and landlords undertaking bathroom or kitchen renovations, using the Water Efficiency Label to guide product selection adds a relatively small amount of time to the specification process but can reduce the long-term water bill of the property significantly. A comprehensive bathroom with A-rated basin taps, an A-rated toilet suite, and an A-rated showerhead will use approximately 40 to 50 percent less water than the same bathroom fitted with G or F-rated products of equivalent visual quality.
Prestige Engineers can advise on water-efficient product selection when specifying plumbing fixtures for London renovation projects and can supply and install Water Efficiency Label-rated products across all product categories. For landlords looking to reduce water costs across a property portfolio, a systematic programme of replacing the highest-consumption fixtures with rated equivalents can be structured as a rolling replacement programme to spread the capital cost while delivering progressive reductions in water bills.