In the case of Ayyaswami Gounder v. Munnuswamy Gounder (1984), the Supreme Court ruled that a co-owner has the right to use common property to their maximum advantage. The only restriction imposed by law is that the user must not prejudicially affect or cause injury to the other co-owner.

2)  In subsequent rulings, such as Jayaraman v. Perunayammal (2007), the Madras High Court explicitly set aside restrictions that limited water usage to specific survey numbers. The court permitted co-owners to draw water from a common well to irrigate newly acquired or alternative lands under a workable rotational turn system, provided the other party's volume/time share remains entirely untouched. 

3) issue legal notice detailing your registered 50% undivided share, the established turning system, and the Supreme Court precedents allowing flexible usage. Warn him that any physical obstruction will attract civil and criminal liability.

4) File a civil suit for a Permanent Injunction in the local Munsif Court to restrain the co-owner from interfering with your water withdrawal on your turn days. Crucially, file an Interim Injunction Application (Under Order 39, Rules 1 & 2 of CPC) alongside it. While the main suit may take time, an Interim Injunction order can often be secured within a few weeks to a couple of months, legally barring the co-owner from stopping you while the case is active

1. Protecting Your Right to Use Your Share of the Water

Under the Indian Easements Act and established Tamil Nadu High Court precedent, a co-owner of a well is entitled to enjoy the common property in the most advantageous manner, provided it does not prejudicially affect the other co-owner's rights. The right to draw water is generally considered co-extensive with the right to irrigate one's land, and the source of irrigation is inseparably connected with the ownership of the land. If you draw only your 50% share on your designated turn days, without causing detriment to the other co-owner's equal share, a court is likely to protect your right and may grant an injunction restraining him from interfering. The legal principle is that each co-owner is entitled to reasonable user of the common property.

2. Securing a Permanent Water Right for Your Sister's Land

This is legally precarious. The consistent view of the Madras High Court is that a co-owner's right to water from a shared well is inseparably connected with the lands originally entitled to irrigation from that source, and it is not open to a co-owner to take water to irrigate any newly acquired or unconnected land. Since your sister's deed does not include a share in the well, her land has no legal nexus to the well. To secure a permanent, legally recognised right for her land, she would need to independently acquire a share in the well or obtain a registered easementary right from all co-owners, which the other co-owner is unlikely to grant voluntarily. A mere pipeline extension from your share is unlikely to withstand a court challenge as a durable right for her plot.

Since  a 50% undivided co-owner of the well, you have an equal right to enjoy the water during your allocated turn. However, co-ownership of a well is generally held to serve the specific dominant tenement (the land parcel for which the well share was created/appurtenant to).

Courts in Tamil Nadu have drawn a distinction between using your allocated turn for your land versus piping/siphoning water to an adjoining property that holds no deeded water rights.

Free agricultural service connections (SC numbers) provided by TANGEDCO are bound by strict terms. Using an agricultural power connection registered for Survey No. A to supply water across survey boundaries to Survey No. B (which lacks a sanctioned water source/connection) can be treated by TANGEDCO as an unauthorized extension or misuse of free power if reported by an opposing party.

Since you and your sister purchased from the same vendor, check the parent title documents. If the vendor originally enjoyed water rights over the entire undivided block before selling 60 cents to your sister and 113 cents to you, an easement by necessity or quasi-easement may exist.

If there is no compromise settlement is sighted, you may plan to file a suit for permanent injunction praying the following

• Declaration of your right to draw water during your 50% turn without restriction on destination, provided it is purely agricultural.

• Permanent Injunction restraining the co-owner from physically obstructing the laying or operation of a pipeline during your turn day.

Before that you may check if the 2018 sale deeds or earlier parent documents reference the common well rights for the entire block prior to division. 

Yo0u can even think about sending a formal legal notice to the co-owner of the well stating that your turn rights are absolute for 1 day out of 2, that drawing water during your turn day causes zero loss or harm to his turn day and also warn him that any physical obstruction will result in civil litigation and administrative actions before the RDO/Police.

Your registered 50% undivided share in the well is an important starting point. However, the extent of your right to use the water must be determined from your sale deed, the documents governing the well, and any established arrangement regarding alternate-day use.

1. Can you supply water to your sister’s adjoining land on your turn day?

Potentially, yes, but it is not automatic. Your co-ownership gives you rights in the well, but it does not necessarily entitle you to change the purpose or geographical extent of its use. The other co-owner may argue that the well and its water rights were acquired specifically to irrigate your own survey number.

Your position would be stronger if the deeds contain no restriction on the destination of water, the proposed pipeline does not interfere with the other co-owner’s use, and the arrangement does not increase the burden on the well or its electricity connection. The fact that your sister’s land is adjoining and the water will be used only for agriculture may support your case, but does not conclusively establish the right.

Before laying the pipeline against the other co-owner’s objection, the relevant documents and the historical usage should be examined.

2. How can you prevent the other co-owner from obstructing your use?

If your documents and the applicable law establish your entitlement, you may seek an injunction from the competent civil court against unlawful interference with your lawful use of the well. If the matter is urgent, interim relief may also be considered.

However, an injunction protecting your existing right to draw water is not necessarily the same as an order authorising you to supply water to a different parcel of land. The relief sought must be framed around the precise right you can establish.

3. How can your sister obtain a permanent water right?

The more durable solution would be to establish an express, legally enforceable right for your sister’s land, rather than depending indefinitely on your personal permission to use your share. Depending on the title documents and the nature of the rights involved, this may require a properly drafted and registered instrument creating an appropriate water-use right or easement, with the consent of the persons whose rights would be affected.

Your own 50% share does not automatically authorise you to burden the other co-owner’s rights or grant your sister a right binding upon him. If his consent is legally necessary and he refuses, a permanent right may require a court determination; it cannot simply be created by describing the arrangement as a family or agricultural arrangement.

4. What about the free agricultural electricity connection?

This point should not be overlooked. The electricity connection may be subject to conditions governing its use, and those conditions should be checked before the proposed arrangement is implemented. The fact that the water is used for agriculture and no commercial activity is involved does not, by itself, establish compliance with every applicable condition.

My recommendation: First establish the precise scope of the water right under the registered deeds and the documents governing alternate-day use. That will determine whether a limited injunction is viable and whether a permanent instrument can be executed without the other co-owner’s consent. This document-based distinction is crucial: otherwise, you could spend money on litigation that protects your existing share but does not secure the permanent right you want for your sister.