Do I need an RO water purifier?

Only if your input water needs it. RO is necessary for dissolved contaminants such as fluoride, nitrate, arsenic, uranium and high salinity. On low-TDS treated municipal supply, a UV or UV+UF purifier handles the microbial risk without stripping minerals or wasting 2 to 3 litres per litre purified.

Govt CGWB 2024 + 2025 data

What's in your district's groundwater? Look it up.

Q: What does a contaminant flag mean?

A flag means a CGWB Annual Ground Water Quality Report (2024 or 2025) lists at least one monitored location in the district above its threshold: EC over 3000 microsiemens per cm, fluoride over 1.5 mg/L, nitrate over 45 mg/L, iron over 1.0 mg/L, arsenic over 0.01 mg/L, uranium over 30 ppb, manganese over 0.3 mg/L, lead over 0.01 mg/L, or zinc over 15 mg/L. The 2024 and 2025 rounds are shown side by side. It does not mean every source in the district is affected, and absence from the list is not a clean-water certificate.

Q: Where does this data come from?

Every flag is extracted from the Central Ground Water Board's Annual Ground Water Quality Reports 2024 (NHS 2023-24, 15,259 monitoring locations) and 2025 (pre-monsoon 2024 location annexures), with the year cited on each contaminant. The 2025 release added manganese, lead and zinc. The dataset is refreshed with each annual CGWB release.

Look up any district to see what the government's CGWB groundwater reports found in its water: fluoride, nitrate, arsenic, uranium, iron, salinity and now manganese, lead and zinc from the 2025 release, checked against the BIS drinking-water limits. It is the same official data, made readable, so you know what is actually in the water where you live.

…

districts flagged

15,259

CGWB monitoring wells

contaminants tracked

11,721

location-level readings

India's groundwater, in 3D

Drag to look around, double-click or scroll to zoom, and click any district to open its report. Switch to "By contaminant" and tap a contaminant below to highlight only the districts where it was found.

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India's most affected states

Interactive ranking from the CGWB 2024 and 2025 reports. Switch contaminants, then click any state to browse its districts. .

Water quality by state & district

CGWB 2024 and 2025 groundwater findings for every monitored district in India. Tap a state to expand.

Andaman & Nicobar Islands2 flagged

Andaman & Nicobar Islands groundwater quality by district from the CGWB 2024 and 2025 reports (2 of 4 monitored districts flagged):

North & Middle AndamanNorth & Middle Andaman water quality: flagged for iron, manganese in 2025 (not monitored in 2024) South AndamanSouth Andaman water quality: flagged for high salinity, fluoride, iron, manganese in 2025

Andhra Pradesh26 flagged

Andhra Pradesh groundwater quality by district from the CGWB 2024 and 2025 reports (26 of 26 monitored districts flagged):

Arunachal Pradesh3 flagged

Arunachal Pradesh groundwater quality by district from the CGWB 2024 and 2025 reports (3 of 25 monitored districts flagged):

ChanglangChanglang water quality: flagged for iron in 2024; iron, manganese in 2025 Papum ParePapum Pare water quality: flagged for fluoride, iron, manganese in 2025 TirapTirap water quality: flagged for iron in 2024

Assam29 flagged

Assam groundwater quality by district from the CGWB 2024 and 2025 reports (29 of 36 monitored districts flagged):

Bihar37 flagged

Bihar groundwater quality by district from the CGWB 2024 and 2025 reports (37 of 38 monitored districts flagged):

Chandigarh1 flagged

Chandigarh groundwater quality by district from the CGWB 2024 and 2025 reports (1 of 1 monitored districts flagged):

ChandigarhChandigarh water quality: flagged for manganese in 2025

Chhattisgarh23 flagged

Chhattisgarh groundwater quality by district from the CGWB 2024 and 2025 reports (23 of 31 monitored districts flagged):

Dadra & Nagar Havelino flagged

Dadra & Nagar Haveli groundwater quality by district from the CGWB 2024 and 2025 reports (0 of 3 monitored districts flagged):

Delhi11 flagged

Delhi groundwater quality by district from the CGWB 2024 and 2025 reports (11 of 12 monitored districts flagged):

Goa1 flagged

Goa groundwater quality by district from the CGWB 2024 and 2025 reports (1 of 2 monitored districts flagged):

North GoaNorth Goa water quality: flagged for nitrate, manganese in 2025

Gujarat34 flagged

Gujarat groundwater quality by district from the CGWB 2024 and 2025 reports (34 of 39 monitored districts flagged):

Haryana22 flagged

Haryana groundwater quality by district from the CGWB 2024 and 2025 reports (22 of 23 monitored districts flagged):

Himachal Pradesh9 flagged

Himachal Pradesh groundwater quality by district from the CGWB 2024 and 2025 reports (9 of 13 monitored districts flagged):

Jammu & Kashmir8 flagged

Jammu & Kashmir groundwater quality by district from the CGWB 2024 and 2025 reports (8 of 22 monitored districts flagged):

Jharkhand24 flagged

Jharkhand groundwater quality by district from the CGWB 2024 and 2025 reports (24 of 27 monitored districts flagged):

Karnataka33 flagged

Karnataka groundwater quality by district from the CGWB 2024 and 2025 reports (33 of 34 monitored districts flagged):

Kerala17 flagged

Kerala groundwater quality by district from the CGWB 2024 and 2025 reports (17 of 17 monitored districts flagged):

Ladakhno flagged

Ladakh groundwater quality by district from the CGWB 2024 and 2025 reports (0 of 2 monitored districts flagged):

Lakshadweepno flagged

Lakshadweep groundwater quality by district from the CGWB 2024 and 2025 reports (0 of 1 monitored districts flagged):

Madhya Pradesh50 flagged

Madhya Pradesh groundwater quality by district from the CGWB 2024 and 2025 reports (50 of 52 monitored districts flagged):

Maharashtra36 flagged

Maharashtra groundwater quality by district from the CGWB 2024 and 2025 reports (36 of 40 monitored districts flagged):

Manipur1 flagged

Manipur groundwater quality by district from the CGWB 2024 and 2025 reports (1 of 16 monitored districts flagged):

SenapatiSenapati water quality: flagged for iron, manganese in 2025

Meghalaya9 flagged

Meghalaya groundwater quality by district from the CGWB 2024 and 2025 reports (9 of 13 monitored districts flagged):

Mizoram1 flagged

Mizoram groundwater quality by district from the CGWB 2024 and 2025 reports (1 of 10 monitored districts flagged):

MamitMamit water quality: flagged for nitrate in 2025

Nagaland9 flagged

Nagaland groundwater quality by district from the CGWB 2024 and 2025 reports (9 of 14 monitored districts flagged):

Odisha30 flagged

Odisha groundwater quality by district from the CGWB 2024 and 2025 reports (30 of 34 monitored districts flagged):

Puducherry2 flagged

Puducherry groundwater quality by district from the CGWB 2024 and 2025 reports (2 of 5 monitored districts flagged):

KaraikalKaraikal water quality: flagged for fluoride in 2025 PondicherryPondicherry water quality: flagged for nitrate in 2024; manganese in 2025

Punjab22 flagged

Punjab groundwater quality by district from the CGWB 2024 and 2025 reports (22 of 24 monitored districts flagged):

Rajasthan33 flagged

Rajasthan groundwater quality by district from the CGWB 2024 and 2025 reports (33 of 36 monitored districts flagged):

Sikkimno flagged

Sikkim groundwater quality by district from the CGWB 2024 and 2025 reports (0 of 4 monitored districts flagged):

Tamil Nadu45 flagged

Tamil Nadu groundwater quality by district from the CGWB 2024 and 2025 reports (45 of 46 monitored districts flagged):

Telangana39 flagged

Telangana groundwater quality by district from the CGWB 2024 and 2025 reports (39 of 42 monitored districts flagged):

Tripura7 flagged

Tripura groundwater quality by district from the CGWB 2024 and 2025 reports (7 of 9 monitored districts flagged):

DhalaiDhalai water quality: flagged for iron in 2024; nitrate, manganese in 2025 GomtiGomti water quality: flagged for iron in 2024; manganese in 2025 KhowaiKhowai water quality: flagged for iron in 2024; manganese in 2025 North TripuraNorth Tripura water quality: flagged for nitrate, iron in 2024; nitrate, manganese in 2025 SipahijalaSipahijala water quality: flagged for manganese in 2025 South TripuraSouth Tripura water quality: flagged for iron in 2024; manganese in 2025 West TripuraWest Tripura water quality: flagged for nitrate in 2024; nitrate, manganese in 2025

Uttar Pradesh77 flagged

Uttar Pradesh groundwater quality by district from the CGWB 2024 and 2025 reports (77 of 80 monitored districts flagged):

Uttarakhand12 flagged

Uttarakhand groundwater quality by district from the CGWB 2024 and 2025 reports (12 of 13 monitored districts flagged):

AlmoraAlmora water quality: flagged for fluoride, nitrate, arsenic in 2024; fluoride, iron in 2025 BageshwarBageshwar water quality: flagged for nitrate, iron, manganese in 2025 ChamoliChamoli water quality: flagged for iron, manganese in 2025 ChampawatChampawat water quality: flagged for iron in 2024; nitrate, iron in 2025 DehradunDehradun water quality: flagged for nitrate, iron in 2024; iron, manganese in 2025 HaridwarHaridwar water quality: flagged for nitrate, iron, arsenic, uranium in 2024; iron, manganese in 2025 NainitalNainital water quality: flagged for nitrate, iron in 2024; iron, manganese in 2025 Pauri GarhwalPauri Garhwal water quality: flagged for iron, manganese, zinc in 2025 PithoragarhPithoragarh water quality: flagged for nitrate, iron in 2025 Tehri GarhwalTehri Garhwal water quality: flagged for iron in 2024; iron, manganese in 2025 Udham Singh NagarUdham Singh Nagar water quality: flagged for nitrate, iron, arsenic in 2024; iron, manganese in 2025 UttarkashiUttarkashi water quality: flagged for iron in 2024; fluoride, nitrate, iron in 2025

West Bengal22 flagged

West Bengal groundwater quality by district from the CGWB 2024 and 2025 reports (22 of 23 monitored districts flagged):

How this lookup works

Frequently asked questions

Is this my tap water quality?

No. The data comes from CGWB groundwater monitoring wells, not household taps. Municipal piped supply from treated surface water usually tests better. Use this as your district baseline, then confirm your own tap with a TDS meter and, where contaminants are flagged, a lab test.

What does a contaminant flag mean?

It means a CGWB report (2024 or 2025) lists at least one monitored location in the district above the threshold. The two rounds are shown side by side per contaminant. It does not mean every source in the district is affected, and absence from the list is not a clean-water certificate, since monitoring wells are sparse.

Do I need an RO purifier?

Only if your input water needs it: dissolved contaminants such as fluoride, nitrate, arsenic, uranium or high salinity. On low-TDS treated municipal supply, UV or UV+UF handles the microbial risk without stripping minerals or wasting water.

Where does this data come from?

The Central Ground Water Board's Annual Ground Water Quality Reports 2024 (NHS 2023-24, 15,259 monitoring locations) and 2025 (pre-monsoon 2024 location annexures, which added manganese, lead and zinc). Each contaminant shows both years with the year cited. The dataset is versioned and refreshed with each annual release.