Updated 26 October 2026. An earlier Property Point guide (Flood Prone Areas in Bangalore 2026: Lake Buffer Check Before Buying) said we had found no report that the drain buffer cut was finalised; it was, in October 2025, and the new gazette now restates it. The pages ranking for this search give the 15/10/5 figures but not the new measurement rule, the unmapped-drain rule, the single-line nala rule or the lake tiers now in force. This guide adds them.

Rajakaluve buffer: old vs new

On a plot beside a primary drain, the strip you cannot build on falls by 35 m (our arithmetic). That is why some plots once inside the buffer may now be buildable, subject to everything else being in order.

  • Primary drain: 50 m before, 15 m now (BLR Post; TalkingLands).
  • Secondary drain: 25 m under RMP-2015 (some activists cite 35 m from the NGT era), 10 m now (TalkingLands).
  • Tertiary drain: 15 m under RMP-2015 (25 m in the NGT-era framework), 5 m now (TalkingLands).
  • Drains below tertiary: no fixed buffer; revenue records apply (TalkingLands).

What the 17 October 2026 gazette adds

  • Drains are classed as primary, secondary or tertiary, with buffers of 15, 10 and 5 m on each side (NammaWard).
  • Measured from the edge of the drain as recorded in revenue records (NammaWard). Earlier guides disagreed on whether the old figures ran from the centre or the edge (TalkingLands), so this settles the point for new approvals.
  • Buffers apply even if the land-use map does not show the drain, nala, tank or lake (NammaWard).
  • A single-line nala that joins a secondary drain or a water body is treated as tertiary, so it carries a 5 m buffer (NammaWard).
  • A non-primary drain between two sites does not by itself bar amalgamation, but the buffer must be protected, the nala land stays public and authorities keep access (NammaWard).

Lake buffer zone in Karnataka now

Lake buffers are separate and follow the Karnataka Tank Conservation and Development Authority Act. The amendment, now Karnataka Act No. 19 of 2026, was notified on 18 February 2026 after the Governor's assent on 16 February; it replaces the uniform 30 m buffer with tiers based on size (Propheadlines, 20 February 2026). As described for the bill (SANDRP, 10 February 2026, citing Bangalore Mirror):

  • Lake up to 1 acre: 3 m.
  • 1 to 10 acres: 6 m.
  • 10 to 25 acres: 12 m.
  • 25 to 100 acres: 24 m.
  • Above 100 acres: 30 m.

What is allowed inside a buffer?

In lake buffers, roads, bridges, water lines, STPs, underground drainage and power lines may be built with the Authority's prior approval, provided tank capacity and natural flow are not reduced; commercial, industrial and entertainment uses are barred (Propheadlines). Drain buffers are no-build strips for floodwater, maintenance and access (TalkingLands). A structure on the drain itself remains an encroachment however small the buffer (TalkingLands).

Why the buffer cut is contested

Bengaluru has about 1,000 km of rajakaluves (The South First, 2 October 2025). When the draft was published, citizen groups led by Bengaluru Town Hall called the cut unscientific and warned of more flooding, lower groundwater recharge and loss of green cover, and asked for the notification to be withdrawn (The South First). They also pointed to earlier court rulings that treated 30 m as a minimum buffer (The South First). The same report notes that feeder drains below the tertiary level get no fixed buffer, only what revenue records show.

The state's position, as stated for the lake amendment, is that uniform wide buffers left large areas around small water bodies unusable (Propheadlines). For a buyer, the practical point is that the rule is both new and contested, so a plot that is buildable only because of the cut carries more legal risk than one that clears the old buffer too.

Is the rajakaluve buffer cut final? The High Court case

Not settled. A PIL by Janaadhikara Sangharsha Parishat seeks to quash the October 2025 notification. A Division Bench issued notice to the State, GBA and BDA in early June 2026 and listed the matter for 2 September; no interim order was reported, and TalkingLands found no later reporting as of 13 October 2026. The Federation of Bengaluru Lakes has said it is considering a challenge to the lake buffer change (Propheadlines). If either rule is reversed, larger buffers could return.

Buying near a rajakaluve or lake: checklist

  • Get the drain class in writing from the planning authority. Do not rely on a broker's description.
  • Ask for the buffer line on the sanctioned plan, measured from the drain edge per revenue records.
  • Check the village map and RTC for the drain or kere, even if the master plan map does not show one.
  • For a flat, ask whether any part of the building, basement or compound wall sits in the old buffer that was cut in 2025, and whether the approval relied on the new figures.
  • Ask about flooding history in recent monsoons; a smaller buffer does not change how water moves.
  • Ask your lender's legal team for its view; banks check drain proximity (TalkingLands).