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Free check · Bihar · sources up to 2026

Is rainwater harvesting mandatory for your building in Bihar?

Mandatory for plots of 1,000 sq m and above (2006 Act); draft 2026 bye-laws propose 100 sq m and above. Answer a few questions about your plot to see whether it applies to you.

Building

Common buildings in Bihar

The answer for typical plots, new buildings, roof taken as 70% of the plot. Use the checker for your own sizes.

BuildingAnswer
House on a 100 sq yd (gaj) plotNot mandatory
House on a 200 sq yd plotLikely mandatory
House on a 300 sq yd plotLikely mandatory
Villa on a 500 sq yd plotLikely mandatory
Apartment block on 1,500 m²Mandatory
Shop or office on 400 m²Likely mandatory
School on 4,000 m²Mandatory
Factory on 10,000 m²Check locally

For an existing building, tick the box in the checker: most rules are written for new buildings.

The rule in Bihar

Bihar's building bye-laws require rainwater harvesting in buildings, and owners who install it get a 5% holding (property) tax exemption under the Bihar Municipal Property Tax Rules, 2013. An older rule under the 2006 Ground Water Act required RWH in building plans on plots of 1,000 sq m or more. A June 2026 draft of new building bye-laws proposes making RWH mandatory on all plots of 100 sq m or more, but it awaits Cabinet approval.

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Rainwater harvesting cost in Bihar

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Frequently asked questions

Is rainwater harvesting mandatory in Bihar?

Mandatory for plots of 1,000 sq m and above (2006 Act); draft 2026 bye-laws propose 100 sq m and above. Bihar's building bye-laws require rainwater harvesting in buildings, and owners who install it get a 5% holding (property) tax exemption under the Bihar Municipal Property Tax Rules, 2013. An older rule under the 2006 Ground Water Act required RWH in building plans on plots of 1,000 sq m or more. A June 2026 draft of new building bye-laws proposes making RWH mandatory on all plots of 100 sq m or more, but it awaits Cabinet approval.

Is rainwater harvesting mandatory for a 200 gaj house in Bihar?

Most likely yes: rainwater harvesting is required for your building. Bihar Ground Water (Regulation and Control of Development and Management) Act, 2006; Bihar Building Bye-Laws, 2014: plots of 1,000 sq m and above (2006 Act); draft 2026 bye-laws propose 100 sq m and above. It applies from a plot area of 1,000 m² or more; your plot is 167 m².

How do I check if my building in Bihar needs rainwater harvesting?

Enter your plot area, roof area and number of floors in the checker on this page, in square feet, square yards (gaj) or square metres. It compares them with Bihar's rule, Bihar Ground Water (Regulation and Control of Development and Management) Act, 2006; Bihar Building Bye-Laws, 2014, and tells you whether it applies and why.

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