Mapping San Francisco’s thousands of drains

November rains have brought relief to San Francisco, but they’ve also highlighted a problem: The condition of the city’s tens of thousands of storm drains, which are prone to clogging and flooding.

So much so, in fact, that City Hall is looking for a few good men and women to keep an eye on them all.

The city’s “Adopt a Drain Program”—under which the SF Public Utilities Commission [PUC] encourages private citizens to pledge to keep a vigilant watch on a particular drain and keep it flowing during storm time—dates back to 2016.

According to the PUC site, storms sometimes overwhelm San Francisco’s more than 150-year-old sewer system:

In San Francisco, we have a combined sewer system that collects stormwater and sewage in the same network of pipes. While the system is made to handle a significant amount of rainfall, in large rain storms when the system reaches capacity, some low-lying areas of the City, especially areas that used to be creeks or streams, can experience flooding and property damage. No sewer system, including ours, can be designed to manage all the stormwater in all storms.

Of SF’s 25,000 drains, PUC deep cleans about 5,000 per year. Keeping the rest working is up to the volunteers.

What’s new about the two-year-old program is the digital map launched last week that reveals precisely where the city’s critical conduits lie.

According to the San Francisco Examiner, the online tool actually only identifies those 2,000 city drains that are most often the victim of clogging.

But even that count gets a little dizzying, as icons marking sewer and sea drains fall into place on each block in a strangely satisfying spectacle.

Of the 25,000 drains citywide, citizens have only adopted 2,518 of them. It’s not hard to see why: The work is unpleasant, and it’s hard to shake the feeling that, in an ideal world, PUC would have sufficient staff and funding to take care of them properly.

Nevertheless, a little civic pride goes a long way, and a quick perusal of nearby blocks really does reveal a surprising number of neglected inlets.

It’s a dirty job. But someone really does have to do it every now and then.

PS: For those looking to roll up their sleeves in the East Bay, Oakland offers both a similar program and map.

• Adopt a Drain [SF PUC]
• Drain Map
• Drains Map Urges Residents To Keep Clear [SF Examiner]