How to design a water efficient home
Early design considerations
There are many ways to implement water conservation measures in both new and existing homes. However, it is more cost effective to integrate water efficiency measures early on in the design and construction phase of buildings when one can consider how design features would relate to the water distribution network and other water supporting systems. It certainly is considerably more cost-effective to integrate a rainwater harvesting system during the build process rather than at the post construction stage.
Whoever you intend to use to design your home, you should ask them to incorporate water-conserving devices/systems within the specification, most of which will come at little or no additional cost when incorporated as part of the initial build, providing immediate cost savings once you move into your green home.
Overview of key water conservation measures
- Taps account for more than 15% of indoor household water use.
- Tap aerators should replace all taps that run around 15 L of water per minute as they could reduce the flow rate to as little as 6 L per minute.
- By reducing the average length of a shower by two minutes, a family of four can save up to 60 000 L of water in a year.
- Simple and inexpensive timers are available to alert users of the time spent in a shower.
- In an ordinary shower cycle, as much as 50% savings can be achieved by turning the water off while shampooing your hair or washing your body.
- Low flow showerheads are also a great way to reduce water usage. Showerheads should use less than 10L of water per minute and can go as low as 6L per minute.
- Toilets are by far the main source of water use in the home, accounting for nearly 30% of residential indoor water consumption, making them attractive targets for water efficiency improvements.
- There are a number of high-efficiency toilet options, including dual flush technology. Dual flush toilets have two flush volumes: a full flush for solids and a reduced flush for liquids only.
- If you are on a tight budget, plastic bottles filled with water (and carefully placed inside the cistern) and the so-called toilet dam (a barrier placed inside the cistern, creating a dry compartment) can serve a similar purpose as both reduce the amount of water used in each flush, saving up to 3 L of water per flush.
- Greywater reuse in toilets is a further possibility but it requires additional pipes, pumps, a storage unit and a simple treatment unit. It can be costly to retrofit so include this measure during the design phase.
- Water-rating labels help consumers choose more efficient washing machines.
- Greywater from laundry operations can be subjected to basic treatment and made suitable for reuse. It can be reused to flush toilets. It can also be used for outdoor irrigation. Therefore, plans to capture and reuse greywater from laundry operations should be considered during the design phase of new buildings.
- Water leakage from toilets, faucets, or plumbing fixtures can be responsible for as much as 30% of water losses. Therefore, detecting and repairing leaking fixtures forms a good starting point for efficiency improvements in existing buildings.
- By conducting regular checks and routine maintenance, considerable amounts of water can potentially be saved.
- Smart leak detectors placed on your incoming water line can be a great addition. These devices can detect slow insidious leaks, as well as catastrophic burst pipes, and shut your water off and thus alerting you of the problem
Optimization irrigation systems
- When choosing an irrigation set-up, drip irrigation systems should be prioritised over above ground sprinkler systems to minimise evaporation.
- In addition, synchronising irrigation to changes in soil moisture content is more efficient than relying on pre-set frequencies. Obtaining a simple device to continuously monitor the soil moisture content can result in significant efficiencies.
- All irrigation systems should as a minimum have a rain sensor attached to prevent watering during rain showers. Integrated weather monitoring systems can also reduce irrigation usage by up to 30%.
- Harvesting rainwater from roofs and storing it in rainwater harvesting tanks for future use rather than allowing it to runoff into storm water drains or create urban floods, is not only an eco-friendly alternative but will also save you money as you will not be using expensive municipal water.
- Rain is a FREE water source and stored rain can be used for most household cleaning, watering the garden, flushing toilets and washing cars and filling up pools and fish ponds.
- Greywater is the generic term given to waste water from showers, baths, washing machines and wash-hand basins in your home.
- Simple greywater systems can be installed to immediately distribute the water to the garden for irrigation. Properly treated and stored, this water can also be recycled and reused for flushing toilets.