Ken Schwencke is a data journalist and co-founder of The Thrust. Previously, he's worked at The New York Times and the Los Angeles Times. More from this author →
A while back, I remember reading a Bob Pool story in the L.A. Times about researchers who spotted all of the pools in the L.A. County basin using satellite imagery. They totaled up just over 43,000, but left out large swaths of the county by focusing solely on one part of the county.
That project came to mind while browsing the L.A. County Assessor's data, where I noticed a flag indicating a pool. A little more research shows that there's a use code specifically single family homes with a pool.
First off: there are a lot more than 43,000 pools. Counting up all of the pools in the county, there are just over 250,000. And most of them, 96%, are in single-family homes. Conversely, only about 18% of homes in L.A. have a pool.
When you filter down to those places, you start to see a pattern emerge. For example, there are very few residential pools in the inner parts of L.A. city. They're concentrated in the hills and the San Fernando Valley, as you can see in the map above.
In the rest of the county, they're in the suburbs, the mountains and independent cities like Beverly Hills and Santa Clarita.
The heaviest concentrations, places where more than half of homes come with their own oasis, are in wealthy enclaves with airy names: Hidden Hills, Bel Air, Rolling Hills, etc.
These hillside homes are beautiful, multi-million dollar affairs. They're the homes of CEOs and Real Housewives, and their neighborhoods are filled with shimmering blue pools of all shapes and sizes.
But if you take the 405 to the 105 to the 110, there are central neighborhoods like Vermont Vista where you can go for blocks without seeing a private pool. Few homes in these poorer city neighborhoods have pools, and a good portion are un-filled. Some of the ones that are filled, are filled with refuse.
In Southern California, both space and water are increasingly rare. Rate of pool ownership then serves as a decent proxy for neighborhood wealth. A pool in Calabasas is far different and more common than one in Compton.
One of the fascinating parts of researching this is in the difference between homes and pools across the county. To that end, the map at the top of the post lets you randomly roam from pool to pool. Enjoy.
Notes I used Mapbox GL for both the main map and the embedded locator. The parcel shapes are served from a custom vector datasource, which lets me filter and display them on the fly in a lightweight fashion. Further, the parcel information is served up and shuffled from a csv, but there's a cron continually creating a sample of the data. That way you never have to download the full 10 megabytes.
A version of this blog post appeared on schwanksta.com on Dec. 1, 2015.
Sources L.A. County Assessors parcel data