San Francisco’s Urban Water Cycle


Cartographer(s): Phil Frank
Date: 1995
Place: San Francisco
Dimensions: 91.5 x 61 cm (36 x 25 in)
Condition Rating: VG+

In stock

Phil Frank’s depiction of San Francisco’s unseen water management system.


In 1995, the San Francisco Water Department commissioned three poster-maps by local cartoonist Phil Frank. The objective was to create vivacious renditions of the systems that supply San Francisco and the Bay Area with fresh drinking water and handle sewage and other excesses in a safe and sustainable manner. This particular poster shows the city’s so-called ‘Urban Water Cycle,’ which essentially implies the subterranean system of pipelines, sifting tanks, and pumps that handle all of the city’s sewage and wastewater flows.

While a separate poster focussing on the Hetch Hetchy Water System shows how San Francisco and the Bay Area are supplied with fresh drinking water from the Sierra Nevadas, this poster illustrates how that water is dealt with once it has been used within the city. An additional feature  – and one that, despite its crucial function, is rarely thought about by the broader populace – is how the system has been designed also to handle large storm flows and heavy rain.

In Frank’s delightful rendition of this rather technical subject, we see clearly how underground pipelines funnel water in and out of the city. While fresh drinking water is supplied through pipelines from the south, the ensuing wastewater – as well as any potential storm flows – ends up in underground sifting tanks, allowing sediments (i.e. gunk and crap) to sink to the bottom, from where it is pumped to a wastewater treatment facility. The clean water at the top of the tank (including rainwater) can then be flushed safely into the Bay without causing environmental harm.

While the subject matter of this poster may be somewhat technical, we all must acknowledge that it is systems such as these that allow any great city to thrive. Phil Frank’s whimsical style makes an otherwise niche subject accessible to all and is both educational and humorous at the same time. It is a poster that, in our assessment, will become an icon in the visual arts pertaining to San Francisco’s urban infrastructure.


At the bottom of the image, we find a text box that provides an excellent explanation for the imagery, as well as the motivation behind compiling this poster map in the first place. It reads:

The San Francisco Public Utilities Commission is responsible for the City’s water and wastewater systems. An average of 72 to 77 million gallons of water per day is treated and distributed to San Francisco’s businesses and homes. The City’s water quality is constantly monitored and kept at one of the highest levels in the nation. City employees work around the clock to ensure that everyone has an adequate supply of water and pressure throughout the City.

SF Public Utilities Commission’s Clean Water Department is responsible for treating everything that enters San Francisco’s combined sewer and stormwater system. In heavy rains, 500 million gallons of water can be dumped into the City’s lines in one day. The Clean Water Department is committed to keeping San Francisco’s sewer system working smoothly, safely, and efficiently.

Since water pipes and sewer lines are underneath the City’s streets, this poster was created to illustrate how these vital services are delivered to your home. This poster is a third in a series aimed at educating San Francisco’s future leaders. The other two posters dealt with the Hetch Hetchy Water System (where San Francisco gets its water) and the distribution system within the City. For copies of this poster, contact the San Francisco Water Department at (415) 923-2571.


On the verso of the map, the function and technical complexity of San Francisco’s water systems are further expounded in a series of text boxes and illustrations. These both instruct viewers how to read the map and provide the necessary context to truly appreciate the genius of modern wastewater management.


Phil Frank

Phil Frank (1943 – 2007) was a prolific cartoonist who created two comic strips, Farley and The Elderberries. He lived in Marin County. Frank had a keen interest in history and served as the president of the Sausalito Historical Society.

Condition Description

Very good.