Q: How do I write a problem statement for my thesis on 'Productive uses of domestic water supply in rural households'?

Detailed Question -

As per policies, the supply is meant only for domestic uses, but people use it for activities beyond domestic use.

1 Answer to this question

Conceptually, a problem statement has to discuss three things: the present state regarding the problem, the desired or ideal state, and the solutions or remedies you will suggest through your study in attaining the ideal state.

Coming to your topic, the present challenge is that people in rural households are putting domestic water supply to uses other than the original intent. So, you need to think about things like: Is there a surplus supply? Will the extraneous use lead to a shortage in the future? If they have a surplus (which seems rather unlikely, due to water management being a global challenge), could it be put to better use?

The ideal state could be two-fold: they use it for the original purpose, or if there is surplus, they think of better ways of utilization (in case they are not presently).

Finally, possible solutions could be incentives for appropriate use (or disincentives for inappropriate use), storage in the case of a surplus, and rationing in the case of a shortage.

Of course, these are only (our) examples. You would know your topic better, and thus be able to work through to your problem statement better. For which, you may find the following resources useful:

Hope this helps. And all the best for your thesis!