Chennai Metrowater will soon begin issuing notices to owners of large buildings, asking them to install greywater recycling systems in their premises.
The water agency is ready to serve notices to 10,000 buildings, including multi-storied structures, hotels and institutions. It is also preparing a technical advisory on greywater recycling, officials said.
In 2017, Metrowater had issued a circular asking new multi-storeyed and special buildings to make arrangements for separation of bath water for reuse. Now, the water agency has started insisting on greywater recycling in existing buildings too and use reclaimed water for flushing toilets and gardening as per building rules.
The Tamil Nadu Combined Development and Building Rules, 2019 have also specified measures to be taken for greywater recycling to obtain planning building permission. They also describe recycling methods for greywater treatment.
According to the Bureau of Indian Standards IS 1172, on an average, bathing contributes to 28% of the total water consumption at the household level. Potable uses like drinking and cooking contribute to less than 10% of water use, given that a person consumes 135 litres per day.
Experts note that reuse of bath water would go a long way to conserving freshwater sources. Several residential complexes and individual houses are now looking to reuse wastewater. New technologies are also available for domestic consumers.
Sureshkumar Samuel, director (sales), Ecotec Engineers and Consultants, said sewage treatment plants of small capacity to treat a minimum of 1 kilolitre are available and these could be built underground. The cost of these facilities starts from ₹1 lakh. Many individual house owners are now installing such facilities and reusing water, he said.
