Is it permissible to fix the share price for buying and selling shares in the future when liquidity is available? And is Zakat obligatory on selling water? And how can a new, fair distribution of shares be achieved if the father sells land he owns and adds the amount to the well project to develop it using solar panels, knowing that the current number of shares is unequal among the partners?

It is permissible to divide the well into shares. The value of each share is estimated by what the father spent on the land and excavation. Whoever pays money owns shares commensurate with what they paid. Buying and selling among siblings or from the father is permissible by mutual consent. It is not permissible to force anyone to sell what they own or to relinquish their profit. If the father buys for his children at a fixed price lower than the market price, this is a gift in which justice must be observed among the children, especially if there are minors among them. Profits are distributed according to the number of shares, with the possibility of allocating a percentage to the project manager. If the father develops the project with his own money, he becomes a partner with the shareholders according to what he paid, and he can gift what he developed to his children, provided justice is observed. It is permissible to sell water after owning and possessing it. There is no zakat on what is not intended for sale. Zakat is obligatory on what is intended for sale, such as water, its containers, money, and debts, if it reaches the nisab and a year has passed.