Seattle under Seattle and a Technical Definition

Water resources engineers like weird technical terms. One of those terms is head, which was explained to me as the height of the geyser that would occur if you were to poke a hole in a pressurized pipe. Right. Super clear. I was reminded of this term on my first day of class (getting ready for our trip to Jordan), during the Underground Tour of Seattle. The first settlers in Seattle built houses right on Elliot Bay. They also built outhouses right on Elliot Bay, and when the tide would come in, it would sweep sewage right out from under their outhouses and out into Elliot Bay. Lovely.

When the modern toilet, aka the “Crapper” (named incidentally for Thomas A. Crapper) came to Seattle, it was an extremely popular item. The problem with the Crapper was that it had to connect to a city sewer network, so the people of Seattle hastily installed a six-inch wooden box pipe (what is Manning’s n for a wooden pipe?) that drained into Elliot Bay. When the tide came in, it would cause sewage to back up the pipe and into people’s Crappers. Some reports say the resulting seawater/sewage geyser was as high as three to four feet above the toilet level (Source: Mary, tour guide for The Underground Tour). So here we have another definition of head: the height of a geyser that occurs when you flush your toilet during high tide in downtown Seattle.


In 1889, a fire in a glue factory burned down much of the downtown Seattle area. Being the smart city planners they were, they decided to build the new Seattle on top of the old city, high enough to mitigate the sewer geyser problem, allowing sewage to drain as gravity intended. Our tour today led to an interesting discussion during class about the density of seawater—1029 kilograms per cubic meter—versus sewage—approximately 729 kilograms per cubic meter (Source: However, I can’t guarantee the accuracy of the  value for sewage density because I don’t know: a) how many gallons per flush the Crapper used, b) the quality or lack thereof of the toilet paper at use in pre-20th century Seattle, and c) how much water Seattle citizens were drinking nor how much roughage they were eating on a daily basis. On the whole, 729 seems like a good number, mostly because I definitely don’t want to do more research on the subject.

Speaking of sewage, after the tour, I bought a book on the history of Seattle. I took my book, sat down under a tree in Pioneer Square, and cracked it open randomly to page 287. A bird crapped on my book about the Crapper. As Forrest Gump once said, “It happens.”