Environmentally-aware developers are now designing the layout of their properties with the aim of conserving water and with a focus on rainwater management. Reducing water consumption and protecting water quality are recognised as key objectives of sustainable design, and certain measures also make excellent economic sense.

There are many ways to conserve water when building a new property, ranging from making architectural decisions that limit domestic water consumption, to landscape designs which use effective water harvesting systems. Water harvesting is the collection and storage of rainwater from paved surfaces, rocks and the landscape features. It usually has direct filtration as its goal. Once collected, harvested water can be stored in tanks above or below ground, or in ponds. Gravity-flow water systems are the most energyefficient way of using harvested water. However it is sometimes impracticable to use this method, as the water is often stored at a level lower than where it is subsequently utilised and pumps are therefore required. Solar power is an effective way to power pumps if they are needed, as it is cheaper to store water than to store electricity.

or drinking water, physical filtration is a popular option. A simple screen or sand filter will remove coarse particles from collected water, while a high-tech ceramic filter will remove bacteria and even viruses. Roof washers are an excellent pre-filter for drinking water harvesting systems. Before allowing water into the storage tank they divert the first few litres of rainwater over the roof surface, removing accumulated dust and contaminants.

Architectural design has a huge impact on levels of domestic water consumption and conservation, so collection and recycling are all important issues for developers. Not all domestic appliances and fittings use the same amount of water. Dual flush toilets, low water-use washing machines and shower heads, and good quality plumbing to reduce leakages, are all effective ways of limiting domestic water consumption and are reasonably easy to source and install.

Materials that are lead-polluting need to be eliminated from a site as they contaminate the water supply. This is especially important when choosing roof tiles. Fitting gutters to the roof and collecting the water in a tank under the house is becoming a popular practice in Thailand. A 200 square metre roof can collect an amazing 4,000 litres of water from just 20mm of rainfall. Pervious paving materials also reduce and filter surface runoff.

Roof water and grey water can be used for various on-site activities. Grey water is water that has been used for activities such as washing. It is no longer suitable for domestic purposes, but can be re-used for watering gardens or washing cars or patios. It is important to remember that collecting and conserving rainwater takes a certain amount of advance planning and the design needs to be incorporated into developments from the beginning.

This article is provided courtesy of Phuket Villas & Homes as part of the company's corporate responsibility programme.