Is $20 a day enough for two people?

Yes, if you avoid alcohol, tourist traps, and private taxis. You will be living a very local lifestyle.

How do I get around cities cheaply?

Use local buses or cycle rickshaws. Always negotiate the price for a rickshaw before you get in.

Can I really drink tap water if I filter it?

Use a specialized purifier like a Grayl that removes viruses and bacteria. Do not just use a standard carbon filter.

Backpacking India as a Couple on a $20 Daily Budget

To stay under $20 total per day as a couple, prioritize sleeper class trains, eat exclusively at local vegetarian 'thali' joints, and book private rooms in budget guesthouses for $8–$10. Stick to secondary cities and avoid Western-style cafes or tourist-oriented bottled water brands.

Choose your transport wisely. Book 'Sleeper Class' trains via the IRCTC website or the ixigo app at least 2 weeks in advance. It is the cheapest way to cover massive distances and doubles as your accommodation for the night.
Master the 'Thali' economy. Eat where the locals queue. A standard unlimited vegetarian thali (rice, dal, vegetable curry, roti) costs $0.75–$1.20 per person. Skip restaurants with English menus.
Vet your accommodation. Use apps like Booking.com or Agoda to filter for guest houses under $10. Call ahead or show up in person to negotiate a 'long-stay' discount if you plan to stay more than 3 nights.
Filter your own water. Do not buy plastic water bottles. Carry a LifeStraw or a Grayl filter bottle to make tap water safe. This saves you roughly $2–$3 per day.

Is $20 a day enough for two people?: Yes, if you avoid alcohol, tourist traps, and private taxis. You will be living a very local lifestyle.
How do I get around cities cheaply?: Use local buses or cycle rickshaws. Always negotiate the price for a rickshaw before you get in.
Can I really drink tap water if I filter it?: Use a specialized purifier like a Grayl that removes viruses and bacteria. Do not just use a standard carbon filter.