In Tamil Nadu, which has a profusion of tanks, local irrigation institutions have evolved to develop a common code for maintenance, water-sharing and resolution of conflicts. The organisational structure operates, firstly, at a supervisory level as an enforcing authority, and, secondly, at a more menial level involving hard labour. The first level of officials is called nattamaikar (a group of persons representing the entire village) or kavaimaniyam (generally one person). While the kavaimaniyam is an irrigation functionary concerned exclusively with organising maintenance work, nattamaikar organises irrigation-related activities as well as other village functions such as temple festivals.

The nattamai and kavaimaniyam are assisted by irrigation workers called neerkatti , whose major responsibilities are to inspect the inlet channels during monsoon months, and to inform the nattamaikar or kavaimaniyam about breaches or illegal tapping of water by upstream farmers. The neerkattis also watch the bunds and surplus weirs, particularly during floods, irrigate lands as per the directions of the kavaimaniyam or nattamaikar , and protect the crop from cattle. The number of neerkattis varies from one to 10 depending upon the size of the command area. They are paid in kind every season by the farmers of the concerned tank command. Generally, wages are pooled on the basis of the command area cultivated, and shared equally among the irrigation workers.

The nattamai or kavaimaniyam generally call a meeting of the landholders in the command area as soon as a tank starts receiving water through its feeder channels. Neerkattis announce the meeting by beating drums. The meeting decides when to start the maintenance work and the contribution of labour by each landholder. If a landholder fails to contribute his labour, he must provide a substitute with hired labour, failing which he is liable to be fined. In some tanks, the kavaimaniyam maintains a record on the extent of labour involved in maintenance work.