The answer to your question is, "it depends." Virginia City's Mackay Mansion was built ca. 1861 and claims to have the first indoor flush toilet in the Nevada Territory. Virginia City's Fourth Ward School, opened in 1877, had flush toilets, but they were an innovation for many of the students, so they had a trigger mechanism in the seat that caused it to automatically flush when the student stood up after sitting.

Plumping allowed for drainage in much of the community, dumping sewage far down the ravine (and to the east, down wind!), and many businesses and houses were acquiring flush toilets throughout the 1860s and 1870s, but there was also ample evidence of outhouses, many of which survive (and even more survived into the late twentieth century - and were still in service). I have spoken to many people raised in Virginia City in the 1930s and 1940s who were embarrassed when they made friends with people in nearby Reno, for example, and found that those people had flush toilets. Inviting people from Reno up to their Virginia City houses would have exposed their primitive living conditions, even into the mid-twentieth century.

A source to consider is my book, The Roar and the Silence: A History of Virginia City and the Comstock lode (1998)