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Notes on Selection of Suitable Showers

• Details of the showers registered under the WELS on showers for bathing are uploaded to the website of the Water Supplies Department for public information. The details include the nominal flow rate data together with the water efficiency grading of the showers. The information can facilitate consumers or other relevant parties to select showers suitable for their plumbing systems.
• Before choosing water efficient showers (such as that with Grade 1 water efficiency rating), consumers are advised to check whether their existing showers are operating at low flow condition. This condition may be due to the low water pressure in their premises, e.g. a premises situated at the top 3 floor of a building without pressurisation installation. If such condition exists, consumers should choose suitable showers which generally allow larger water flow in low pressure condition. This can avoid affecting the operation of the water heater. One should note that showers which are operated under low water pressure could also be water-saving. Should there be any queries about choosing showers, please contact relevant retail shops or water heater suppliers.
• To check the maximum flow rate of your existing shower before purchasing a water-efficient shower, you may wish to adopt the following simple method:
  
      Tool
  • a bucket (of at least 10 litres capacity);
  • a one-litre measuring container with calibration marks accurate to at least 0.5 litre (i.e. 500 c.c.) or other appropriate volume measuring devices; and
  • a watch that shows seconds (preferably with stop-watch function).
    
    Procedures
  • fully turn on the cold water tap of your shower outlet and wait until the water flow is steady;
  • quickly put the bucket below the shower outlet for 10 seconds (ensure that all the discharged water is collected by the bucket during the 10 seconds of testing time);
  • quickly move away the bucket from the shower outlet;
  • turn off the water tap;
  • measure the volume of the water collected (Q litres) by using the measuring container; and
  • calculate the flow rate (f) (in litres per minute) by multiplying the volume of the water collected (Q) by six, (i.e. f = Q x 6 ).

The water efficiency grading of the WELS showers is:

If the measured flow rate of your shower is below 9 litres per minute, the performance of your shower is already comparable to that of a Grade 1 WELS shower.