C1.2 Water quantity and demand management
Throughout Australia, cities, towns and communities are confronting the reality of water shortages. In some communities, water shortages are seasonal or caused by drought. Others, however, face dire water shortages that threaten the viability and long term sustainability of the community. Wherever there is a shortage of water, it is necessary to look at ways to manage the use of, or demand for, water. This is called ‘demand management’.
In communities where water use is high, children are often blamed for wasting water by leaving taps running. This is not confirmed by water use data collected during Housing for Health projects over a 15-year period and involving over 6,000 houses.
Housing for Health teams do, however, regularly find dripping taps, leaking hot water system pressure relief valves, and leaking toilet cisterns, see B1.3 ‘Taps’. A dripping tap can waste between 100 and 600 litres of water a day, therefore poorly maintained plumbing fittings are a significant cause of water wastage in communities.
From existing survey data, the following calculation indicates the impact of apparently insignificant water wastage. In the example below, based on the real tap failure figures nationally, not only is close to 2 million litres of water wasted daily, much of this water flows into waste water systems causing overloading of the systems or failure.
Example of water wastage caused by tap failure
Number of taps in a house (shower x 2, basin x 2, laundry tub x 2, washing machine x 2, yard x 2, a toilet cistern stop tap and cistern valve, hot water relief valve, hot water stop valve, maybe a hot water system cold water relief valve, maybe bath taps x 2 kitchen sink x 2, isolation valve) 20 Taps
Approximately 25% of taps fail at testing, see B1.3 Water outlets, valves & taps. 5 Failed taps
Assume that only half of these failures result in water leaks as the other failures could be due to handle faults or taps jammed but not leaking. 2.5 Number of leaking taps per house
If each of these taps has a leak of 100 litres per day (or 4 litres per hour) 250 litres will be lost through leaks per day per house
Water wastage every day from approximately 7,500 houses surveyed (before fix work was commenced) 1,875,000 litres of cold and hot water per day wasted
The combination of good housing design, specification and maintenance has a significant impact on water usage. For example, a well designed house will reduce the amount of time that active cooling is needed and this can reduce the water consumption of an evaporative cooling system. The problem of leaking taps is easy to fix. An effective plumbing maintenance program to repair leaks in pipes and replace washers in taps is the first and most important demand management strategy that can be implemented. Using water meters on community supply tanks, and at each house, is a simple way to detect leaks early and to measure water use and demand in the community. Repairs can then be targeted to leaks that are detected through the monitoring program. A regular program to reseat taps and replace washers can also prevent leaks. Reducing the pressure in the supply system can also lessen leaks in pipes and taps.
Providing water efficient appliances such as low flow plumbing fixtures and water efficient washing machines will also save water. Before installing low flow plumbing fixtures, check how the water quality might affect them. Although appliances such as washing machines may not be provided by the housing organisation, it may be cost effective to provide or subsidise high quality, water efficient washing machines rather than building additional water infrastructure.
Community programs that educate residents about water use and ways to save water, such as the Waterwise program in Queensland can assist in managing demand. Charging for water, particularly for excessive water use, has also been used as a strategy to reduce water use. https://www.qld.gov.au/environment/water/residence/use
Rainwater tanks have been proposed elsewhere in this guide as a means of providing potable water to houses. In communities where potable water is readily available, rainwater tanks can be used for watering gardens or for evaporative air conditioners as a way to reduce demand on the potable water supply.
Design and Specification
Consider
When planning housing projects, consider:
- installing water meters to houses
- using water efficient plumbing fittings and appliances
- providing large capacity rainwater tanks to all houses, supplying garden taps and/or an evaporative cooling system
- treating grey water from the laundry and bathroom, and then using it in underground irrigation systems
- planting drought tolerant grasses, shrubs and trees, particularly plants that grow in the local area.
If involved in planning a community water supply system or demand management program, consider:
- the expected growth of a community and develop strategies to meet the demand for water from proposed developments without exhausting the available water sources
- installing water meters on mains supply pipes and all buildings, located in an accessible location above ground, and monitor meter readings to target urgent plumbing maintenance
- implementing a local, regular plumbing maintenance program and charging for excessive water use
- providing rainwater tanks to all buildings in the community
- installing sub-surface tanks or developing swales and small dams to collect stormwater run-off in the community
- installing a second reticulation system in the community to provide recycled water to landscape areas and toilets.
Quality control
- water meters have been installed and are easy to find
- COMPLETED DESIGN & SPECIFICATION
DURING CONSTRUCTION
AT HANDOVER
- COMPLETED DESIGN & SPECIFICATION
- if specified, water efficient plumbing fittings and appliances are fitted
- COMPLETED DESIGN & SPECIFICATION
DURING CONSTRUCTION
AT HANDOVER
FINAL COMPLETION
- COMPLETED DESIGN & SPECIFICATION
- pipes are secure and there is no water hammer (movement of unsecured pipes) that could break pipe joints and cause leaks in the wall cavity
- DURING CONSTRUCTION
AT HANDOVER
FINAL COMPLETION
- DURING CONSTRUCTION
- rainwater tanks are correctly installed, see ‘Design and specification’ in B4.1 ‘Quality of drinking water’ for information about installing rainwater tanks
- DURING CONSTRUCTION
AT HANDOVER
FINAL COMPLETION
- DURING CONSTRUCTION
- if specified, grey water fixtures are connected to a treatment system before discharge to an underground irrigation system
- COMPLETED DESIGN & SPECIFICATION
DURING CONSTRUCTION
AT HANDOVER
FINAL COMPLETION
- COMPLETED DESIGN & SPECIFICATION
- there are no water leaks.
- DURING CONSTRUCTION
AT HANDOVER
FINAL COMPLETION
TRADE TEST
- DURING CONSTRUCTION
- water meters have been installed and are easy to find
Maintenance
As part of cyclical maintenance:
- record meter readings and identify leaks in houses or the pipe work between houses in the reticulation system
- Local Maintenance Team, Housing Management
- 3 Months
- check all taps, spouts and shower roses, including yard taps and pressure relief valves, for leaks
- Plumber, Local Maintenance Team
- 12 Months
- check pipes for water hammer and in-ground leaks and repair or replace
- Plumber
- 12 Months
- check pipes for water hammer and in-ground leaks and repair or replace
reseat taps and replace washers in taps every two to three years depending on water quality
- Housing Management
- 24 Months
- check toilet cisterns for leaks and repair, if necessary
- Local Maintenance Team
- 12 Months
- flush out grey water irrigation systems
- Plumber
- 12 Months
- clean the pads in evaporative coolers
- Plumber
- 12 Months
- clean ‘first flush’ diverters and insect screens on rainwater tanks.
- Local Maintenance Team
- 6 Months
- record meter readings and identify leaks in houses or the pipe work between houses in the reticulation system
Standard And References
Department of Water 2006, Report for the Minister for Water Resources on Water Services in Discrete Indigenous Communities. Department of Water, Perth
Remote Area Developments Group 2000, National Assessment of the Colilert field test kit in remote Aboriginal Communities in Australia. Murdoch University, Perth
Anda, M and Ryan, J 1998, Saving water for healthy communities: a workbook for Aboriginal communities, Remote Area Developments Group, Murdoch University, Perth, pp 11
Khalife, MA, Dharmappa, HB & Sivakumara, M 1998, “An Evaluation of Septic Tank Performance in a Remote Australian Village Provides Insight for Optimizing Onsite Treatment Systems”, Journal of Water Environment Research, Edition 4, Volume 10, USA, Water Environment Federation, pp 33 - 36
Pholeros, P 1997, Energy and Water Use Required for Health in Housing on the Anangu Pitjantjatjara Lands North West of South Australia, for UPK Nganampa Health Council Inc., Alice Springs, p 13.
Pholeros, P, Rainow, S and Torzillo, P 1993, Housing for Health, Towards a Healthy Living Environment for Aboriginal Australia, Healthabitat, Newport Beach, pp 39 - 45.