This is the second part of a series devoted to the source of San Francisco’s (and much of the Bay Area’s) water: the Tuolumne River.

Since I dipped my toes in the upper Tuolumne River for the first time a few weeks ago, I have felt privileged to drink water daily from such a pristine source.  Every time I turn on the tap in San Francisco, I am connected by pipeline umbilical cord to a clear river running over granite through a meadow in Yosemite National Park.  I am connected to the silvery trout that dart from shadow to shadow and to the land that the river dissolves into it as it flows. I am connected to the tree roots the river scoured free of earth and the momma bear that waded across belly-swelled.

We are lucky. Us Tuolumne drinkers.

And in the spirit of what I mentioned last week, of taking a second to begrateful and knowledgeable about the source of our water, today I will tell the story of the path of the Tuolumne.  There are multiple stories. But today, I will start from the beginning, before there were humans and dams and reservoirs, before the water came to our taps, when the Tuolumne was just a river doing its river thang.

West of Tioga Pass, high up in the Sierras, deep in what is now Yosemite National Park, the Tuolumne has its beginnings. Lyell Fork is its primary source. Where Dana Fork meets Lyell, the river meanders its way through Tuolumne Meadows. Some of you may have been there before. High above Yosemite Valley, at 8,600 feet, the meadow stretches for miles under big blue sky.

As it leaves the meadows, the river drops down sheer granite stairs and falls into its namesake canyon- the Grand Canyon of the Tuolumne.  And now, the stories begin to diverge. For this pre-human story, the river continues its drop out of the Sierras and into the foothills, where it meets a few smaller tributaries. The Middle and South Fork of the Tuolumne join in the foothills, along with the Clavey River and the North Fork of the Tuolumne.

The river’s almost to the Great Valley’s floor. As its descent ends, its pace slows- there’s no hurry to get anywhere, lolly-gagging on the valley floor. Until it meets the San Joaquin River.  This is where the journey of the Tuolumne as a separate river ends, as it joins at its mouth with the San Joaquin, its waters carried to the Bay of San Francisco and out into the Pacific.

The path of the Tuolumne.

Frequently Asked Questions:

Doesn’t San Francisco get its water from Hetch Hetchy?

San Franciscans will tell you, with pride, that their water comes from Hetch Hetchy. Which is a part truth.  The well-engineered Hetch Hetchy system does bring water from the Tuolumne River to Bay Area taps. So, in that sense, our water comes from Hetch Hetchy. But the Tuolumne River fills Hetch Hetchy’s pipes.

O’Shaughnessy Dam was built on the Tuolumne River. And Hetch Hetchy is the reservoir behind the dam, which holds the waters of the Tuolumne River so that during dry months, we will be able to sustain ourselves.

Who else gets Tuolumne River water besides San Francisco?

The San Francisco Public Utilities Commission sells water directly to customers who live within San Francisco. The SFPUC also sells ‘wholesale’ water to 26 other cities and water  districts that then sell the water to their customers. Water is sold to cities within San Mateo, Santa Clara, and Alameda Counties.

Why do people say that San Francisco’s water is so pure?

85 percent of San Francisco’s water comes from the Tuolumne River. And water that comes from the Tuolumne is NOT filtered. That means that the water is so clean and pure that it exceeds water quality standards and only needs to be disinfected (with chloramine). Tuolumne River water is some of the only water in the country that is allowed to be unfiltered as it comes out of our taps.

Next week, the second story will be told, of the Tuolumne River and the Hetch Hetchy Water Project that got the Tuolumne to our taps.