Rajakaluve and Lake Buffer Zones: An Encroachment Check for Bengaluru Buyers

In a 2016 drive that shook Bengaluru, bulldozers moved through parts of the city flattening structures that had been built over storm water drains, leaving owners who had paid in full staring at rubble. Many of them had bought in good faith, on layouts that looked legitimate, never knowing their walls stood inside a rajakaluve buffer the law required to stay clear. The flooding that had swamped the city that year had forced the issue. For a buyer today, a beautiful plot by a drain or a lake can carry a risk that no paint or price can hide.

The short answer. A rajakaluve is a storm water drain, and Bengaluru keeps buffer strips clear of construction along drains and around lakes. The buffers that have applied are roughly 50, 35 and 25 metres for primary, secondary and tertiary drains, and about 75 metres around lakes under a 2016 green tribunal ruling, though the exact figures have been litigated and a 2025 proposal may cut them. The trade off is stark: a buffer or lake bed property may look cheap and scenic, but it carries genuine demolition and flooding risk, so verifying the drain and buffer position is not optional.

What is a rajakaluve and why does the buffer matter?

A rajakaluve is a storm water drain, part of the network that carries Bengaluru rainfall away through the city roughly 1,000 kilometres of channels. The law keeps a buffer strip along each drain, and around lakes, clear of permanent construction, so that water can flow, the drain can be maintained, and the natural drainage of the city is not choked. When those buffers are built over, the water has nowhere to go, which is a large part of why Bengaluru floods so badly in heavy rain.

For a buyer, the buffer is not an abstract environmental rule, it is a direct risk to your money and your home. A property that sits inside a buffer or over a drain can be marked for removal and can flood repeatedly, and neither problem is curable once you own it. The scenic plot backing onto a canal or a lake, often sold at a tempting price, is exactly the one that most deserves a hard look at the drainage maps before you believe the view.

How wide are the buffer zones in Bengaluru?

The buffer widths that have applied in Bengaluru scale with the size of the water body or drain, and the table below sets out the figures that have been in force. They derive from directions of the National Green Tribunal and related court orders, applied prospectively rather than to every old structure at once.

Treat these numbers as a guide, not gospel, because the buffers have been fought over in court for years and the figures have shifted between orders. A draft regulation under consideration in 2025 proposes to cut the drain buffers sharply, to as little as 15, 10 and 5 metres, which tells you how fluid this area is. Before you rely on any figure, confirm the buffer that currently applies to your specific property with the BBMP and the latest orders, as reported by outlets such as The South First.

What happens to a building inside a buffer or on a drain?

A structure inside a buffer or over a drain faces two serious and connected threats: demolition and flooding. Authorities in Bengaluru have surveyed buildings near drains and lakebeds and demolished those found to be encroaching, acting on tribunal and court directions, which is what happened in the 2016 drive. A property identified as an encroachment can be served notice and removed, and your registered sale deed does not protect a structure the law says should never have been there.

The flooding risk runs in parallel and is almost guaranteed rather than merely possible. A home built in the path water naturally wants to take will flood when the drain fills, year after year, damaging the structure and your belongings. This is closely related to the risk of building plan deviations we cover in our guide to sanctioned plans and deviations, because a structure in a buffer is, in effect, a deviation from what the city permits on that land.

Are the buffer rules changing?

Yes, the buffer rules are under active review, and that uncertainty is itself something a buyer must factor in. A draft regulation in 2025 proposes to reduce the storm water drain buffers substantially, and separate moves have touched the protection of smaller water bodies. Supporters argue the old buffers sterilised too much land, while activists warn that cutting them will make the city more flood prone. Where that debate lands will shape which properties are safe to build on.

For you, the practical lesson is not to pick a side but to recognise that the rule may differ between the day you inquire and the day a dispute arises. A buffer that is legal today could be challenged tomorrow, and a structure built relying on a reduced buffer could face trouble if the reduction is struck down. The safe path is to stay well clear of drains and lakes rather than to bet on the most permissive reading of a contested rule.

How do you tell if a property is in a buffer or on a drain?

You find out by checking the property against the official drainage and revenue records, not by trusting the seller or the look of the land. Compare the survey number and the plot boundaries with the storm water drain and lake maps and the revenue records held by the BBMP and the revenue authorities, which show where drains and water bodies run. A plot that looks like dry land today may sit on a filled drain or a former lakebed that the records still remember.

Because these overlays are technical, it is worth engaging a local engineer or lawyer to map the drain alignment onto the specific site, especially for a plot or an independent house near any channel or water body. This sits alongside the approval checks in our guide to plot approvals across the BDA, BBMP and panchayat, because a layout approved by the wrong authority or over a drain is the classic trap. If the plot abuts a drain or lake, make the buffer question central.

One revenue record clue is worth knowing by name. Land classified in the records as kharab, and especially B kharab, is land the government historically marked as unavailable for cultivation, often because a drain, tank bund or water channel runs through it. A plot that includes or abuts kharab land is a strong signal to dig deeper, because such land frequently cannot be built on and can overlap exactly with the buffers in question. If you see a kharab notation anywhere near your plot, do not let a seller brush it aside as a technicality.

How should a Bengaluru buyer protect themselves?

Buffer risk is almost entirely avoidable with a few deliberate checks, so build them into your process for any property near water. Work through this seven step checklist.

1. Note whether the property is near any drain, canal, lake or low lying land, which raises the buffer question.
2. Pull the storm water drain and lake maps and compare them against the exact survey number and boundaries.
3. Check the revenue records for any note that the land was a drain, tank or lakebed in the past.
4. Confirm the current applicable buffer with the BBMP, since the figures have changed and are under review.
5. Engage an engineer or lawyer to overlay the drain alignment on the specific plot before you commit.
6. Walk the site after heavy rain if you can, to see where water actually collects and flows.
7. If any part of the structure or plot falls in a buffer or over a drain, treat it as a reason to walk away.

None of this is advice about any particular property or locality; it is the drainage due diligence that separates a safe home from one that can be demolished or flooded. The owners who lost homes in 2016 were not reckless, they simply never checked the one map that mattered. A few hours with the drainage and revenue records, before you pay, is the cheapest flood and demolition insurance a Bengaluru buyer can buy.

Frequently asked questions

What is a rajakaluve and why does its buffer matter?

A rajakaluve is a storm water drain that carries Bengaluru rain runoff, and the law keeps a buffer strip along it clear of construction so water can flow freely. Buying a property built inside that buffer, or over a drain, exposes you to demolition risk and flooding, which is why the buffer is a genuine buyer safety issue.

How wide is the buffer zone around a rajakaluve in Bengaluru?

The buffers that have applied are about 50 metres for a primary rajakaluve, 35 metres for a secondary one and 25 metres for a tertiary drain, with roughly 75 metres around lakes under a 2016 green tribunal ruling. These figures have been litigated and are under review, so confirm the current applicable buffer before you buy.

Can a building inside a buffer zone be demolished?

Yes, it can. Authorities have surveyed and demolished structures that encroached on rajakaluves and lake buffers in Bengaluru, acting on court and tribunal directions. A property inside a buffer or over a drain is not just a flooding risk, it carries a real, documented demolition risk, so it is one of the strongest reasons to walk away.

How do I check if a property is on a drain or in a buffer?

Compare the property survey number and boundaries against the storm water drain and lake maps and the revenue records, which the BBMP and revenue authorities maintain. A local engineer or lawyer can overlay the drain alignment on the site. If the plot abuts a drain or a lake, treat the buffer question as central, not a formality.

Last updated 2026-10-04. PropNewz Team.