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Voluntary Water Efficiency Labelling Scheme on Water Closets

WELS on Water Closets

WELS on Water Closets is a voluntary scheme. It adopts a grading type labelling system.

The water closets applying for registration under the scheme will be tested to confirm its compliance with the performance requirements specified in the scheme. These include flush volume for reduced flush (for dual flush only), solid discharge for maximum flush, paper discharge for reduced flush volume (for dual flush only), liquid contaminant dye retention and drain line transportation distance. The flushing valve of water closet, if applicable, shall be tested in accordance with the relevant requirements as specified in the Waterworks Regulations (Cap. 102A) and comply with the standards specified for the flushing valve of water closet by the Water Authority. In addition, the water closets will be produced/manufactured according to a recognised international quality system (such as ISO 9001 or equivalent).

For a product of toilet suite or combination of a water closet pan and cistern, the water efficiency of the product will be rated to different grades according to the water flush volume of the water closet cistern as shown in Table 1 provided that the accompanied water closet pan shall also fulfill all performance requirements.

For water closet pan alone, it will be rated to different grades according to their minimum water flush volumes required to fulfill performance requirements. For water closet cistern alone, it will be rated to different grades according to their water flush volumes as shown in Table 1.

Grade 1 is the most water efficient whereas Grade 4 is the least water efficient.

Table 1: Conversion of Water Consumption to Water Efficiency Grades for Water Closets

Water flush volume
for full flush:
fF(litres/flush)
Water flush volume
for reduced-flush:
fR (litres/flush)
Water Efficiency Grade Symbolic Presentation on
the Water Efficiency Label
fF ≤ 4.8 fR ≤ 3.2

Grade 1

(Dual Flush)

1 water droplet water droplet.
 fF ≤ 3.2 Not specified

Grade 1

(Single Flush)

4.8 < fF ≤ 6.5 fR ≤ 3.5

Grade 2

(Dual Flush)

2 water droplets water droplet. water droplet.
3.2 < fF ≤ 3.5 Not specified

Grade 2

(Single Flush)

3.5 ≤ fF ≤ 6.5 Not specified Grade 3 3 water droplets water droplet. water droplet. water droplet.
6.5 < fF  Not specified Grade 4 4 water droplets water droplet. water droplet. water droplet. water droplet.

If a water closet has an integral basin or a basin directly connected to it, and the water from that basin is used to flush the toilet, the water saving merit will be shown on the Water Efficiency Label for public information and description of the merited function will be shown in the registration certificate.

The testing methodology is described in Annex 1 of the scheme document with reference to testing conditions and requirements specified in the BS EN  997:2018 – WC Pans and WC Suites with Integral Trap or other equivalent international standards approved by the Water Supplies Department. Details of the testing methodology and technical standard are shown in Annex I of the scheme document.

Commencement of Registration to the Scheme

Registration to the scheme commences on 25 May 2018. No application fee will be charged.

Further Information

WELS on Water Closets is detailed in its scheme document.

Any enquiry on the scheme can be referred to the Water Supplies Department Enquiry Hotline or by fax or by e-mail.

Sample Labels

Sample Label (full version).
Sample Label (full version)