Is rainwater harvesting mandatory for your building?
Answer four questions about your plot. You get the rule for your state, the size it starts at, the law it comes from and what to do next.
When each state makes rainwater harvesting mandatory
The size limit in each state's building rules, from the sources on its rules page. Pick a state for its own checker and examples.
| State | Rule | Covers |
|---|---|---|
| Andaman and Nicobar | Mandatory for plots larger than 100 sq m (Port Blair Municipal area). | residential, commercial, government |
| Andhra Pradesh | Mandatory for plots of 200 sq m and above (new and existing). | residential, group housing, commercial |
| Arunachal Pradesh | Mandatory for residential plots over 2,000 sq m; non-residential plots over 1 hectare (2009 byelaws draft). | residential, non-residential, government |
| Assam | Mandatory for every building (2022 bye-laws); earlier Guwahati rule: buildings of 100 sq m and above. | residential, commercial, government |
| Bihar | Mandatory for plots of 1,000 sq m and above (2006 Act); draft 2026 bye-laws propose 100 sq m and above. | residential, commercial, government |
| Chandigarh | Mandatory for residential plots of one kanal and above; industrial plots above one kanal. | residential, group housing, commercial, institutional, industrial |
| Chhattisgarh | Mandatory for roof area over 500 sq ft (municipal corporations such as Raipur). | residential, commercial |
| Dadra and Nagar Haveli and Daman and Diu | Mandatory for buildings on 1,000 sq m and above (Dadra and Nagar Haveli). | residential, commercial, government |
| Delhi | Mandatory for plots of 100 sq m and above. | residential, group housing, commercial, institutional, government |
| Goa | Mandatory for residential complexes/apartments on 2,000 sq m+; commercial on 1,500 sq m+; industrial on 10,000 sq m+. | group housing, commercial, industrial, government |
| Gujarat | Mandatory for plots of 500 sq m and above (older GDCR); Surat: high-rise or plots over 4,000 sq m. | group housing, commercial, public buildings, government |
| Haryana | Mandatory for rooftop area of 100 sq m and above. | residential, group housing, commercial, government |
| Himachal Pradesh | Mandatory for all urban buildings; NGT (2017) first applied it to buildings over 5,000 sq ft floor area. | residential, commercial, government, industrial, institutional |
| Jammu and Kashmir | No state-wide rule found for Jammu and Kashmir. | not stated |
| Jharkhand | Mandatory for plots of 300 sq m and above (Ranchi). | residential, group housing, commercial |
| Karnataka | Mandatory for sites of 1,200 sq ft (about 111 sq m) and above for new buildings; 2,400 sq ft (about 223 sq m) and above for existing buildings (Bengaluru). | residential, commercial, group housing |
| Kerala | Mandatory for residential: floor area 100 sq m+ and plot 200 sq m+; other occupancies: all new buildings. | residential, commercial, institutional, industrial |
| Lakshadweep | Not mandatory in Lakshadweep. | not stated |
| Madhya Pradesh | Mandatory for plots over 140 sq m. | residential, commercial, group housing, government |
| Maharashtra | Mandatory for plots of 300 sq m and above (urban areas); Mumbai: 500 sq m and above. | residential, group housing, commercial |
| Manipur | Mandatory for plots of 100 sq m and above (existing and new buildings). | residential, commercial, government |
| Meghalaya | Mandatory for buildings above 100 sq m. | residential, commercial, government |
| Mizoram | Mandatory for all buildings (Aizawl; no size threshold). | residential, commercial, government |
| Nagaland | Mandatory for plots of 100 sq m and above. | residential, commercial, government |
| Odisha | Mandatory for Bhubaneswar: plots of 300 sq m and above. | residential, commercial |
| Puducherry | Mandatory for all new buildings (no size threshold found). | residential, commercial, institutional, industrial, government |
| Punjab | Mandatory for buildings above 119 sq yd (about 100 sq m). | residential, commercial, institutional |
| Rajasthan | Mandatory for plots over 300 sq m (municipal areas). | residential, commercial, industrial, public buildings |
| Sikkim | Not mandatory in Sikkim. | not stated |
| Tamil Nadu | Mandatory for all buildings (no size threshold). | residential, commercial, government, group housing |
| Telangana | Mandatory for premises of 200 sq m and above. | residential, group housing, commercial |
| Tripura | Mandatory for new buildings with plinth area over 300 sq m; all group housing. | residential, group housing, commercial |
| Uttar Pradesh | Mandatory for new buildings above 300 sq m (CM directive of Oct 2025: above 100 sq m). | residential, group housing, commercial, government |
| Uttarakhand | Mandatory; no size limit given in the sources. | residential, commercial, government |
| West Bengal | Mandatory for all buildings (2007 rules). | residential, commercial, government |
How the check works
Each state's rule is read from its building bye-laws, government orders and city notifications (sources on the state's rules page). The checker compares your plot, roof or floor area with the limit the rule uses, checks that the rule covers your kind of building, and says when a rule is only for one city, still a draft, or written for new buildings. Leave the roof blank and it takes 70% of the plot.
Frequently asked questions
Is rainwater harvesting mandatory in India?
There is no single national law. Most states make it mandatory in their building bye-laws for new buildings above a plot or roof size, from every building in Tamil Nadu and West Bengal to plots of 100 m² in Delhi and Haryana and 300 m² in Maharashtra and Rajasthan. The checker above has the rule for 35 states and union territories.
Which plot size needs rainwater harvesting?
It depends on the state: commonly 100 m² (about 120 sq yd or 1,076 sq ft), 200 m² or 300 m². Some states measure the plot, some the roof and some the floor area, so the checker asks for all three.
Do existing buildings need rainwater harvesting?
Usually the rule is for new buildings. A few states, such as Andhra Pradesh and Manipur, and cities such as Bengaluru, also cover existing buildings above a size, and most authorities ask for it when a building is rebuilt, extended or applies for a new water connection.
What happens if a building does not have rainwater harvesting?
Penalties vary by state: in Haryana the occupation certificate is withheld; in Delhi properties of 500 m² or more pay 1.5 times the water bill; in Bengaluru homes pay 25% extra on the water bill, rising to 50%; and Delhi, Bengaluru and Tamil Nadu withhold new water connections until it is built.
How is 1 gaj or 1 sq yd converted to square metres?
1 sq yd (gaj) is 0.836 m² and 9 sq ft. A 100 gaj plot is about 84 m² and 900 sq ft; 120 gaj is about 100 m².