Water management for gated communities in Bangalore

1. Install internal water meters

It is possible to track and ration household water usage by installing smart water metres in individual flats. When water is metered and a clear tariff is established, the entire community can become more aware of its water consumption, conserve water and lower its water costs. Water meters are known to reduce water consumption by 35 – 40 percent. The cost of installing water meters in your society varies based on the vendor and includes the meter costs based on their lifespan and capabilities, civil work involved, ease of maintenance, and the billing system.

In short, a meter costs between Rs. 5000 and Rs. 7000. If your apartment community has 50 flats, the estimated cost is Rs. 2 lakh. This seems like a huge upfront capital cost but over 5-6 years, you will not just make up the money spent on tankers but also save water by encouraging individual households to be more responsible in their use of water.

Smart metres allow for billing based on actual usage and could generate additional revenue to cover the society’s water-related expenses.

2. Treat and reuse wastewater

A 2014 BWSSB regulation mandated that all apartment complexes with 20 or more dwelling units must own and maintain a sewage treatment plant (STP) on their premises to treat the wastewater from toilets, baths, showers, kitchens, and sinks draining into the city’s sewers. Treated STP water that is free of foul odour and colour at Vakil Whispering Woods R1 in Chandapura is supplied to household flush tanks and for use in landscaping, says resident Satish Rangamuthu.

Salarpuria Sattva Greenage goes a step further and uses treated water for cleaning of common areas without compromising on residents’ health and comfort. Says Mr. Hitesh, RWA board member of Greenage, “Our community has even come together to make conscious use of RO reject water for the cleaning of common lobbies and for washing cars.” There are also a few instances of residential communities that send their excess treated wastewater to neighbouring parks for groundwater recharge.

3. Harvest rainwater

The BWSSB Act (2009) made rainwater harvesting systems mandatory for all buildings constructed since 2009 measuring 1200 feet and more and buildings built before 2009 measuring 2400 feet and more. By ensuring that your apartment’s RWH systems are functioning well, and effectively and consistently harvesting as much of the rain falling on your premises as possible, including that received during the summer months, your apartment can attain water self-sufficiency. Rainwater harvesting in apartment complexes could include:

A. Digging recharge pits: Unlike borewells which only draw water from underground, recharge wells revive groundwater sources by allowing surface water to percolate into and recharge the groundwater table. These are structures (typically of 3-6 foot diameter and 15-20 foot depth) that can be used to carry rainwater from catchments (rooftop, garden, driveway) into the ground. Recharge pits in an apartment’s premises serve a dual purpose:

• When it rains, runoff water from paved areas, gardens, rooftops, driveways or stormwater drains enters the recharge well, percolates into the shallow aquifer and prevents flooding
• When located close to a borewell and connected to cleaned, filtered run-off from rooftops and terraces, it can recharge the borewell and improve its yield

On average, a recharge well costs between Rs 35,000 – 40,000 to construct, occupies little real estate, and can be constructed in a day. They can be retrofitted or integrated into any real estate development. Recharge wells are a highly impactful, cost-effective and low maintenance measure that every apartment complex can take up to harvest the rain falling on its property, recharge groundwater, and prevent flooding during heavy rains.

B. Direct storage and reuse: With this technique, rainwater collected from the building’s roof and other open areas is directed to a tank with the help of pipes or gutters where it is filtered and stored. In apartments such as Whitefield-based SV Legacy, this is implemented using a dual sump system – one that stores borewell water and another that stores rainwater. Separate overhead tanks are used to store pumped water from these two sumps. Says Sumit Chowdhury, former RWA member of SV Legacy, “In a good rainfall year, this system cuts down our dependence on water tankers by 40 percent of what it is during summer months.”

C. Reviving open wells: If your apartment is fortunate to have an open well on its premises, it could serve as an excellent source of water as well as a point of shallow aquifer recharge when cleaned and connected to rooftops or terraces to channel runoff.

4. Ration water supply

Some communities are tiding over the water crisis with the help of timed water supply on certain days of the week while others are reducing household water supply and even levying monetary penalties on residents who misuse drinking water. Says a resident of a Bommanahalli-based apartment complex, “Our society has started a process of phased water rationing for kitchens in a block wise manner.”

5. Manage common amenities

There are examples of societies temporarily shutting down their swimming pools as a way to prevent wastage of potable water in non-essential uses. Even stricter measures have been adopted in other complexes where access to common toilets has been restricted, and facilities such as the gym and in-house cafes have been closed. Several societies have prohibited the use of hose pipes for washing of cars, balconies and yards and others have shut off access to common taps in the basement and parking areas.

6. Strictly monitor overhead tank levels

The BWSSB in 2020 made installation of automatic water level control systems mandatory for all apartment complexes in the state as a way to prevent the overflow of water automatically from the overhead tanks. Some societies are going the extra mile to ensure judicious use of water. Mr. Rangamuthu, “Our overhead tanks have five levels, but since the onset of summer, security staff have been asked to operate them at four level capacity to avoid spillage and wastage in case of motor failure during power outages. Once the tanks are filled to 80 percent capacity, the motors are switched off.”

7. Build water literacy among residents

It is important now to educate residents, staff and other stakeholders of your society about where their water comes from, the actions they can take to use it judiciously and help conserve it, and the impact that individuals can have in contributing to a sustainable city.