Solving water woes in apartments

“The next world war will be over water” – Ismail Serageldin, former Vice President of the World Bank.

As with any problem, the proper way to manage water is to adopt a holistic approach along the lines of reduce, reuse and recycle and ensure active participation by both individual residents as well as the Apartment Owners Associations.

The Central Public Health and Environmental Engineering Organisation (CPHEEO) guidelines state that the average water consumption per person, in megacities is 150 liters per day (lpd). For an average household of 4 persons, that works out to 600 lpd.

Try to figure out the average household consumption for your building, and the chances are the figure will be significantly higher. For my building – a 14-storied building with 190 apartments – for example, the figure works out to be a huge 860 lpd, 43% higher than the CPHEEO guidelines!

Water demand and supply gap chart in Bangalore. Source: BWSSB

Meanwhile, as urban populations grow explosively, the gap between supply and demand keeps increasing. In Bangalore, for for example, BWSSB supplies 705 million litres per day (MLD) as opposed to a demand of 840 MLD. The shortfall is met from groundwater sources – rampant proliferation of bore wells results in a depletion of groundwater resources and a sinking of water table levels (source:

So, despite the grim situation and looming crisis, why do we continue to consume more than we should? The causes are different, and related to both us as individuals and the way builders construct buildings.

1. Lack of awareness and / or apathy: As individuals, we tend to bury our heads in the sand and pretend a problem will go away if we don’t look at it. So, as long as there’s water flowing out of the tap, we tend not to worry about its future availability and blissfully continue with our water-wasting habits.

water supply in apts

Typical water supply to apartments in a multi-storied building.

2. Inability to monitor individual apartment consumption: The starting point of conservation is accurate monitoring of consumption. Studies have suggested that 20% of the apartments consume 80% of the water – therefore, individual monitoring, had it been possible could be a very effective tool in identifying high-water usage apartments and taking necessary action to curtail the same. Unfortunately, in most apartment buildings, the way the water system is architected, any kind of monitoring (except, of course, at the overall building level) is virtually impossible.

Take my building for example – each bathroom has an independent supply from the overhead tank. One pipe from the overhead tank supplies water to bathrooms of all floors in one column (see illustration) and each kitchen has two independent supplies (one for general water, one for drinking water). Therefore, my 3 bedroom, 3 bathroom apartment has 5 inlet sources that would have to be monitored. At an approximate meter cost of about Rs. 1000, plus installation, you can figure out how expensive it would be to monitor my water consumption accurately. Moreover, the administrative overhead of taking 5 readings for one apartment mean that this is just not a feasible option for any building like mine, where there are 190 apartments.

Why do builders layout the piping in this manner? Simple, it’s much cheaper for them to run a single pipe servicing an entire column of bathrooms, than to run one pipe for each apartment and then branch out to different bathrooms.

3. Range of users with different awareness, education and socio-economic backgrounds: In India today, a typical apartment building is a microcosm of an economy which includes not only the residents, but their domestic help (maids, drivers, etc.) and the building staff (gardeners, housekeeping staff, etc.).

In fact, a significant portion (if not a major portion) of water is actually consumed by non-residents: maids for washing utensils and cleaning apartments, drivers and car wash persons for washing cars, gardeners for watering plants and housekeeping staff for cleaning common areas. A lot of these persons are simply unaware of basic water conservation practices.

4. Lack of efficient plumbing networks: Again, taking my building as a typical example, we have one inlet per bathroom (as mentioned earlier), that provides water for everything – the sink, the shower and the toilet flush. In our case, we depend almost entirely on BWSSB for water (i.e. Cauvery water) and so, the same water that we use in the kitchen for washing vegetables and cooking, is the same water we use for flushing the toilet. Even if we implement a grey water recycling system, we cannot use the water recovered for flushing (which is the single largest use of individual apartment consumption) without a significant redesign of the building’s plumbing system.

An overarching issue is that as a society, India is much less organized than say, the developed western countries. In these countries, the government has a formal way of dealing with water shortages – a multi-tiered system of water usage restrictions with corresponding trigger levels. In Melbourne, Stage 3 water restrictions (triggered when reservoirs are about 35% full), for example, mean that citizens cannot wash cars at home and watering of plants is restricted to certain days and times only. The system works, because almost all the citizens comply with these rules voluntarily – something that has probably no chance of happening in India.

The solution lies in looking at the problem holistically – reducing per household consumption, reusing water from alternate sources like rainwater and recycling some amount of waste water. Here are some strategies the Apartment Owners Associations can employ to help manage water better.

Ways for individual residents to conserve water:

1. Plug all leaks, no matter however small.
2. Use individual outlet controls (normally located below the sink) where possible to reduce the water flow.
3. Personal water-usage related habits: don’t keep taps running while brushing, take short showers or bucket baths, avoid use of bathtub completely.

4. Install low-flow taps and shower-heads and water-saving flushes.

5. Reuse certain types of waste water within the apartment, for example, washing machine waste water for flushing. This, of course, will require significant plumbing work.

1. Education and awareness campaigns: This is probably the single most effective strategy, even though measuring its impact is most difficult. Campaigns should be run continuously, should target all water users – residents, domestic help, staff and so on and should be creatively conceived to grab the attention and interest of all. Taking the help of children to propagate the message is usually quite effective, as their enthusiasm is quite infectious. See the box for a list of obvious, but often neglected, strategies an individual resident can employ to help conserve water. Strategies with a visual impact for example putting up a running count of water consumed on a daily basis, in a prominent place – can also be effective in spreading the message.

2. Water pressure optimisation: The higher the water pressure supplied to the end outlets, the higher the water flow and wastage. Water pressure in all applicable supply pipes to individual apartments should be optimized to provide just enough pressure to ensure an adequate supply. This exercise needs to be carried out in a thorough manner, as pressure varies by floor and time of day (depending on usage).

3. Optimise frequency of cleaning activities: Work with residents to determine an optimal frequency of all cleaning activities relying on common water usage, for example, car cleaning can be restricted to alternate days to save a significant amount of water. Cleaning of common areas like the basement and terrace should be restricted to once a week or once a fortnight.

4. Promote water-efficient devices: Tie-up with leading sanitary ware manufacturers and get them to put up a stall in the building, and offer low-flow taps/shower heads and water-saving flushes to the residents, if possible at a discount. Offer free labour (from the Association) to replace existing fittings with water-efficient ones, as an added incentive.

5. Optimise water used for gardening: Ensure plants are watered early in the morning, when there’s little or no direct sunlight, reducing evaporation losses. Use an effective drip irrigation system, rather than a standard garden hose. Plant more plants that require less water to thrive, for example, create a rock garden with cacti.

6. Implement rainwater harvesting: This has anyway been made mandatory by the Government. Implementing rainwater harvesting with the storage option (as opposed to ground water recharge) can provide an additional source of water supply to meet some of the requirements for uses like car cleaning and gardening. One must, however, be realistic as to the amount of water that can be harvested.

7. Implement grey water recycling: Grey water refers to waste water from the kitchen and the sink / shower area of the bathroom (excluding the toilet). Grey water can be treated relatively easily and the resultant treated water used for non-potable uses like car washing, gardening etc.

In summary, there are a number of ways for both individual homeowners and owner associations to become more water efficient and help bring down the combined usage of the apartment building. The CPHEEO guideline of 150 lpd per person should be treated as the ultimate goal and both residents and the association should continuously strive to bring their per capita consumption as close to that figure as possible.   ⊕


  1. A nice description of the situation of water in urban areas, the problems and possible solutions !

    A good complementary piece to the above is Mr. Shiv Shankar Ranganathan’s article on Water Security for Residents of apartments and gated communities:

    With best wishes,
    India Water Portal

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