Drinking water supply under gst plz assist

Normally registered buyer is required to raise  tax invoice under reverse charge mechanism for purchases from unregistered person and take credit where available.  However, yesterday Govt has announced that supplies upto Rs.5,000 per day  will be exempt from RCM and a consolidated invoice can be raised for whole month for supplies above this limit.

Thank you Sir. So purchase upto 5000 from a non registered person (Per Month?) will be excempted from RCM, right Sir. For us total is less than it for a month even for water 

so I trust we will be excepted from GST RCM on this case

One of me client is engaged in supplying waste water to builders to be used in construction. Builders are asking him for his GST number. Now, under what head will he be registered under GST - Goods/Services. Also, Kindly tell me the HSN code for the same

20 L water cans have 12% GST which was recently revised. The manufacturer has to pay that regardless of his eligibility to pay tax.

I manufacture packaged drinking water in 20 L water cans and give bill to consumers which has 12% GST element in it.