Last edited 04 Nov 2020

Passive water efficiency measures


[edit] Introduction

Passive water efficiency measures are those which require no behaviour change by the user.

[edit] Handbasins

  • Water Saving Taps (efficient versions are as low as 1.7 L/min) are often the same price as less efficient models.
  • Appropriate sink sizing. If a sink does not need to be completely filled to use it, then a smaller sink could be specified.
  • Foam soap requires little water to remove, and generally means less soap and water are used providing further cost saving.

[edit] Low flow toilets

[edit] Urinals

Urinals are often set to flush regardless of use, typically 3 times an hour. A number of devices can be used to control flush frequency:

  1. Siphonic Trap. These contain a barrier fluid which the urine passes through.
  2. Deodorising pad / biological cartridge are fitted to break down bio-film.
  3. Air-flush. Individual traps are replaced by a single trap at the drain end. A low wattage DC fan provides airflow down the bowl to prevent odour. There are no chemicals and they are easy to clean.

[edit] Water Efficient Appliances

Typical washing machines use >50 L/cycle, and dishwashers >15L/cycle. Efficient versions use much less (40L/cycle and 10L/cycle), and modern washing machines often have a 'half load' cycle or intelligent monitoring to only use as much water as needed.

NB Passive water efficiency measures may qualify for tax allowances under the ECA Water Scheme.

[edit] Related articles on Designing Buildings Wiki


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