Drinking water: do not drink the water. Ask for bottled water at restaurants and make sure to confirm ice is filtered water. Most tourist places will be on the look out for this, but best to check. We were told to not even brush your teeth with sink water so we made sure to have bottles on hand in the room as well. On that note: being hydrated helps prevent altitude sickness, while Lima is sea level if you’re planning on going up to Machu Picchu it’s best to start hydrating early.
Restrooms: different places have different rules but most restrooms in Peru like you to throw your toilet paper in the trash can and not the toilet. While this can be gross the city doesn’t have the type of sewer system we’re used to in America, so it’s best to follow the rules. I carried tissue and hand sanitizer in my bag everywhere, but if you just stick to using the restroom at restrains you eat it you’ll be fine. Never pass a free potty.
Spanish speaking: the language of Peru is Spanish but I will say I was surprised by how many people spoke English well. While we had to bumble our way through some conversations (especially with directions) but drinking was easy as we just stuck to pisco sour. Also, having friendly bilingual hotel staff was very helpful.
A note on taxi drivers: on the way back from Ollyantambo we had the best taxi driver who told us all about the sacred valley and some of the history of Peru. He recommended that we stop in Chinchero at 13,000 feet and see how the traditional textiles were made. This was amazing. The ladies showed us how they shave the llamas, then pull the fur into thread. After that the thread is dyed using natural herbs, flowers and berries. They then hand weave into textiles.
Along the way we also saw some alpacas and had to stop for a photo. Alpaca photos are easy to come by, but the people will expect you to tip them, 1 or 2 sol is fine.
If you’re looking for the same taxi experience (which I suggest) call Ricardo, he drives a nice car, speaks great english and is from sunny California!