Is it safe to drink the tap water?

No. Always drink bottled or filtered water to avoid traveler's diarrhea.

Do I need to speak Spanish?

In major tourist areas, basic English is understood. Learning 'Donde está el baño?' and 'Cuánto cuesta?' will get you much further in rural areas.

Two Weeks in Peru: Beyond the Inca Trail

To see the best of Peru beyond Machu Picchu, split your time between the high-altitude Andes of Huaraz, the colonial streets of Arequipa, and the desert coastline of Paracas. Use a combination of domestic flights and overnight luxury buses to cover the massive distances without wasting daylight hours.

Prioritize acclimatization. Fly directly from Lima to Huaraz (3,000m) or Arequipa (2,300m) to start. Spend your first 48 hours doing absolutely nothing strenuous to avoid altitude sickness; drink plenty of coca tea and avoid alcohol.
Use Cruz del Sur for long-haul travel. For bus travel between Lima, Paracas, and Arequipa, book the 'VIP' or 'Cruzero' seats. They recline to 180 degrees, cost about $40-60, and are safer and more reliable than budget carriers.
Book domestic flights for the long stretches. The bus from Lima to Huaraz or Arequipa takes 8-15 hours. Use LATAM Airlines for domestic hops to save days; book at least 3 weeks in advance to keep prices under $120 per flight.
Hire local guides for trekking. In Huaraz, don't attempt the Santa Cruz trek solo unless you are an experienced alpinist. Use local operators in town; they charge about $150 for a fully supported 4-day trek including food and mules.

Is it safe to drink the tap water?: No. Always drink bottled or filtered water to avoid traveler's diarrhea.
Do I need to speak Spanish?: In major tourist areas, basic English is understood. Learning 'Donde está el baño?' and 'Cuánto cuesta?' will get you much further in rural areas.