Editing Tamil Nadu (section)

=== Water supply ===
[[File:Cauvery_at_Erode.JPG|thumb|[[Kaveri]] river is one of the major water sources in the state]]
Tamil Nadu accounts for nearly 4% of the land area and 6% of the population of India, but has only 3% of the water resources of the country. The per capita water availability is {{convert|800|m3|abbr=on}} which is lower than the national average of {{convert|2300|m3|abbr=on}}.<ref name="WR"/> The state is dependent on the monsoons for replenishing the water resources. There are 17 major river basins with 61 reservoirs and about 41,948 tanks with a total surface water potential of 24,864 million cubic metres (MCM), 90% of which is used for [[irrigation]]. The utilizable groundwater recharge is 22,423 MCM.<ref name="WR">{{cite report|url=https://www.environment.tn.gov.in/Document/archives/Waterresources.pdf|page=1|title=Water resources of Tamil Nadu|publisher=[[Government of Tamil Nadu]]|access-date=1 December 2023|archive-date=10 August 2023|archive-url=https://web.archive.org/web/20230810210339/https://www.environment.tn.gov.in/Document/archives/Waterresources.pdf|url-status=dead}}</ref> The major rivers include [[Kaveri]], [[Bhavani River|Bhavani]], [[Vaigai River|Vaigai]] and [[Thamirabarani River|Thamirabarani]]. With most of the rivers originating from other states, Tamil Nadu depends on neighboring states for considerable quantum of water which has often led to [[Kaveri River water dispute|disputes]].<ref>{{cite web|url=https://tnenvis.nic.in/Content|title=Water resources|publisher=[[Government of Tamil Nadu]]|access-date=1 December 2023}}</ref> The state has 116 [[List of dams and reservoirs in Tamil Nadu|large dams]].<ref>{{cite web|url=https://damsafety.cwc.gov.in/?page=Tamil%20Nadu%20Water%20Resources%20Department&origin=front-end&page_id=94&lang=&tp=1&rn=1|title=Dam safety|publisher=[[Government of India]]|access-date=1 December 2023|archive-date=25 December 2023|archive-url=https://web.archive.org/web/20231225061125/https://damsafety.cwc.gov.in/?page=Tamil%20Nadu%20Water%20Resources%20Department&origin=front-end&page_id=94&lang=&tp=1&rn=1|url-status=live}}</ref> Apart from the rivers, the majority of the water comes from rainwater stored in more than 41,000 [[tanks]] and 1.68 million [[well]]s across the state.<ref name="Agri"/>

Water supply and sewage treatment are managed by the respective local administrative bodies such as the [[Chennai MetroWater Supply and Sewage Board]] in Chennai.<ref>{{cite book|title=Second Master Plan|publisher=Chennai Metropolitan Development Authority|pages=157–159|url=http://www.cmdachennai.gov.in/Volume3_English_PDF/Vol3_Chapter07_Infrasructure.pdf|access-date=28 December 2012|archive-date=4 November 2021|archive-url=https://web.archive.org/web/20211104135527/http://www.cmdachennai.gov.in/Volume3_English_PDF/Vol3_Chapter07_Infrasructure.pdf|url-status=live}}</ref><ref>{{cite book|title=Second Master Plan|publisher=Chennai Metropolitan Development Authority|page=163|url=http://www.cmdachennai.gov.in/Volume3_English_PDF/Vol3_Chapter07_Infrasructure.pdf|access-date=28 December 2012|archive-date=4 November 2021|archive-url=https://web.archive.org/web/20211104135527/http://www.cmdachennai.gov.in/Volume3_English_PDF/Vol3_Chapter07_Infrasructure.pdf|url-status=live}}</ref> [[Desalination]] plants including the country's largest at [[Minjur]] provide alternative means of drinking water.<ref>{{cite web|title=IVRCL desalination plant-Minjur|publisher=IVRCL|access-date=12 August 2023|url=http://www.ivrcl.com/desalination.php|archive-date=25 December 2023|archive-url=https://web.archive.org/web/20231225061124/http://www.ivrcl.com/desalination.php|url-status=live}}</ref> As per the 2011 census, only 83.4% of the households have access to safe drinking water, less than the national average of 85.5%.<ref>{{cite report|url=https://data.gov.in/resources/households-access-safe-drinking-water|title=Households access to safe drinking water|publisher=[[Government of India]]|access-date=11 March 2020|archive-date=19 July 2022|archive-url=https://web.archive.org/web/20220719150926/https://data.gov.in/resources/households-access-safe-drinking-water|url-status=live}}</ref> Water sources are also threatened by [[environmental pollution]] and effluent discharge from industries.<ref>{{cite report|url=https://www.environment.tn.gov.in/Document/archives/Waterresources.pdf|page=12|title=Water resources of Tamil Nadu|publisher=[[Government of Tamil Nadu]]|access-date=1 December 2023|archive-date=10 August 2023|archive-url=https://web.archive.org/web/20230810210339/https://www.environment.tn.gov.in/Document/archives/Waterresources.pdf|url-status=dead}}</ref>