please take note that no water tanks can be installed by you your flat 

2)storage of water should only be in society underground and over head tanks 

3) in Mumbai , hoarding "water", in any type of container/tank (or whatever) is illegal and punishable with a fine of Rs. 2500/- AND a continuing offence will lead to revocation of the "occupancy certificate (OC)", to the Society building.

builder is correct in not  making provisions of water tanks inside the flat 

2) most societies in Bombay face water problems . remedy is to opt for boring water in toilets 

3)if you  cancel your flat registration and seek refund builder would levy cancellation charges as per your agreement 

If the project is RERA registered, submit a complaint to RERA authority for deficiency as he has falsely represented that there will be water supply 24/7 as experienced by phase I residents  and seek refund of advance paid with interest. If it not registered under RERA, you can approach District Consumer Commission under new Consumer Protection Act, 2019 under which proceeding are very fast. Even in fist case you can approach District Consumer Commission. Any minor deficiency can be cause of refund and your deficiency is major one. 

There is no provision to provide water tank to store water within the flat.

The water can be stored in the sump located in the ground floor and pumped out to different flats or it can be stored in the over head water tanks located in the terrace. 

it is illegal on part of members to install additional water tanks for storage of water tanks in flats . if any member is aggrieved he can complain to municipal corporation about it . although it is illegal most flats in societies have installed water tanks for storage of water.

However you may note that here is no law which restrict installing such separate tank. 

However since the water connection line is one and common for all the flat owners setting up separate tank for one/two individual flat owners is not allowed by others

Cancellation of the booking of the property can be cancelled by you for the reasons you may rely upon.

However since this reasons is not a valid reason, it will be treated as your own decision to cancel the booking of flat, thereby you may have suffer the loss of deduction of 10# of booking amount as per the conditions of the agreement

Dear Client,

1. 
   Review the Agreement: Review the agreement you signed with the builder carefully. Look for clauses related to possession dates, promised amenities (like 24-hour water supply), and the repercussions for delays or non-compliance.

1. 
   Contact the Builder: Reach out to the builder and express your concerns regarding the water supply and the situation in Phase 1. Seek clarification on their plans to address the water supply issues and inquire about any modifications they might be making to the Phase 2 construction to ensure water availability.

1. 
   Builder's Reputation: Research the builder's reputation, previous projects, and legal history. This could give you insights into their track record in delivering promised amenities and handling similar situations in the past.

1. 
   Approach the Consumer Forums: If you exhaust all negotiations and find yourself in a situation where your rights as a consumer are being violated, you might consider seeking guidance from consumer protection forums.

Regards

Prime Legal

You can cancel the same under rera law without deducting anything 

Hello,

For cancellation of registration and refund you can approach ti MAHARERA authority.