Bore-well usage

Dear Sir,

I am planning to go for bore before start constructing my house. In that area, we can get bore - well water in 400FT. I will have a sump of 5000litres capacity.

In my area, they will provide water, which fulfills one house usage. After 5years, I have a plan to construct 1st floor (another 2 houses).

My question is, If i go for bore-well now, water consumption will be less for 5years. After constructing 1st floor, water consumption will be more (For 3houses).
1. Do I get enough water after 5years? Some persons saying that we couldn't get water after 5years if we not use bore-well regularly.
2. Do I go for bore well now?
3. Please suggest

Regards
Dinesh