Is Rainwater Harvesting Mandatory in Bangalore? BWSSB Rules for Houses and Flats

Rain in Bangalore adds up to between 900 mm and 1,000 mm a year, and a lot of it flows off roofs and roads into drains. A 1,200 sq ft roof can collect about 90,000 litres over twelve months, which could supply a small family's non-drinking needs for several months. This is the thinking behind a duty that touches most houses and apartment blocks in Bangalore. What follows covers the duty, the penalties and what buyers should ask.

How a System Works

All harvesting systems follow one path. Gutters and downpipes lead water off the roof, a filter screens out leaves and silt, and the cleaned water goes to a storage tank, a well for recharge, or a combination. The paved open ground around a building counts as catchment as well, and not just the roof.

A recharge well is normally a ring well of 3 m depth or more, roughly 0.9 m wide, dug where the plot has open land. BWSSB fixes a minimum capacity that grows as the roof and the paved surface get larger, and owners can satisfy it by storing water, recharging the ground or doing both.

Legal Position

The obligation is created by Section 72A of the BWSS Act of 1964. It came in through a 2009 amendment and a later amendment replaced the original wording, notified by the state in October 2021. The regulations are drafted by BWSSB, which enforces them through water connections.

Both owners and occupiers are bound within the BWSSB service area. If a building lacks a system, even a tenant's bill is affected, and the buyer takes the duty over together with the property.

Which Plots Are Covered

Coverage depends on the area of the plot and not on floor area. Since 2009, every new building on a plot of 30 ft by 40 ft, which makes 1,200 sq ft, or more has needed a harvesting structure. Plots of 60 by 40 ft (roughly 2,400 sq ft) and larger are held to a stricter standard: old and new buildings alike must keep rainwater in storage, use it and feed groundwater.

In the text of the Act, this middle threshold appears as 2,325 sq ft (216 sq m), and the 2021 amendment brought older buildings on such plots fully into the rule. At the top, the threshold is 1,000 sq m (roughly 10,764 sq ft) for old and new buildings. At that size dual piping is compulsory, and stored rainwater goes to uses other than drinking, cooking or bathing. Because apartment projects almost always occupy more than 1,000 sq m, it is this band that covers them.

Consequences of Not Complying

A property with no system has an extra monthly line on its water bill, computed as a portion of what is billed for water and sanitation. The proportion rises after three months, is greater for non-domestic connections, and stays until the system is finished and the Board has been told.

Section 72A also lets the Board construct the structure when an owner does not, and then claim back the cost from whoever owns or occupies the property, using the method for unpaid land revenue. It is rarely the opening move, though the power is there. Rates have changed several times, so the local sub-division office can state today's figure. A BWSSB theme park at Jayanagar 5th Block displays models for plots of different sizes.

Budget and Upkeep

A house needs piping, a filter, a storage sump or tank, and a recharge well. Putting everything in during construction is the cheapest course, since the sump and pipes share labour with plumbing. A later retrofit is dearer, mainly because of excavation and alterations to the downpipes.

Upkeep is modest. Roofs and gutters need sweeping before the monsoon starts, the filter needs a rinse several times a season, and the recharge well needs desilting every year. Keep the season's first shower away from the sump, because it carries dust accumulated in the dry weeks.

If You Are Buyers of Houses and Plots

In an independent house, the system counts towards legal standing, as plan approval and khata are. One visit to the site can settle these questions:

• Is the site at least 1,200 sq ft, or at least 2,400 sq ft? Those are the two sizes that count most for a house.
• Are the downpipes, filter and sump or recharge well in place and joined together?
• Does any of the three latest BWSSB bills include a harvesting surcharge?
• Is the sump clean, and is the recharge well open and free of debris?
• Was BWSSB informed about the system, and does the connection record show it?
• If it is a plot, does the construction budget cover all of these parts?

A system is simple to add when the site has open space and hard when the house covers the full plot, so decide where a recharge well could be dug. The seller should settle any surcharge due before registration.

If You Are Buying an Apartment

In a flat, the whole building shares one system, which the owners' association keeps running. A few questions are best put to the developer or the association. How many recharge wells exist, and what is the sump's size? Do the dual pipes bring rainwater or treated water for flushing and gardens?

Is a surcharge visible on the common-area bill? Who cleans the filters and the wells before every monsoon, and what does that cost per year?

A working system means fewer tankers in summer and less water pooling in basements and driveways when it rains heavily. The monthly maintenance charge reflects both. Projects on borewells benefit most, since recharge wells keep those borewells productive.