Sadly, basically, yes, you do have to. It's not very environmentally friendly, so there are ways to get around it. You can boil your water, you can use chlorine tablets (which taste gross, but work), you can use a portable water purifying system, etc. - have a look online to see if you think any of them would suit you. Other than that, though, it's bottled water. It's a bad idea to drink the tap water in India. It's one of the best ways to get sick, particularly if you're only there for a short time. The first time I went, I could drink it at the end of my two month stay, and it was all right, but the next time I was there I cockily had both tap water *and* pani puri after only four weeks there, and I was so sick.