Water-Must drink mineral water only and many good companies in India have mineral water but don't drink tap water. All five star hotels have good purified water and it is safe for brushing your teeth etc.
Voltage-India has 220 voltage so if you are carrying hair dryers or any electric gadget they need converter and also they need adapter because in India the plugs are all round in shape and in USA they are flat.
Rupee is national currency. You can change the currency in all the hotels or at the airport, There are authorized money changes also in cities, do take a receipt whenever you en-cash any foreign currency. Credit cards are accepted at most places. ATM machines are also available at various places
To carry - Sept and beginning of Oct will be still warm actually hot so carry clothes for summer. We suggest people not to carry expansive clothes as there is so much driving and walking and they get ruined. Carry as much as cotton clothes in summers.
Regarding shorts -you can wear them but please remember that in every city you will be going to either a temple or mosque and these are not appropriate for religious places as you need to cover below the knees. Skirts which are below the knee length, capri, pants and jeans are fine. Shirts with short sleeves are fine as well. Also carry good walking shoes as there is lots of walking in the trip.
Please try to travel light. Also you can carry another folding or light bag so that you can fill that with the items you buy in India
As per the Government of India we don’t need any shots but again please check with your doctor. We do recommend to take malaria pills or repellion as some parts in country still Malaria prone.