ST. LOUIS — Ever wonder why St. Louis is shaped like a teardrop, with a long, narrow neck stretching miles northward from the north side to the Chain of Rocks bridge?

It’s all about the water.

“It was about protecting our water sources,” Water Commissioner Curt Skouby explained. “In the beginning, the city’s water intake was just above the present Arch grounds. Then, as sewer outlets moved farther north, water intakes moved upstream above them.”

Today, the city’s primary drinking water source and treatment plant are just above the Chain of Rocks rapids, literally surrounded by two popular myths.

This summer’s floods are hiding one of them: The churning water normally visible from the bridge is not the famous rapids — it’s just a low-water dam built in the 1950s to maintain a minimum level for barges entering Chain of Rocks Lock, the last dam on the entire Mississippi River.

Myth number two: The “castles” in the middle of the river are water intakes. Well, that’s half true. They were replaced long ago by a large modern intake building jutting into the river nearby.

After the Civil War, engineers saw the rapids as a natural low-water dam well-suited for a drinking water intake, but it took three decades to build the castles. Intakes migrated from the present-day Arch grounds to Bissell Point — now a major sewage treatment plant — and then above the Chain of Rocks in 1894.

“Mark Twain wrote a tremendous amount about St. Louis water,” said water production engineer Frank Genovese, standing atop the concrete intake building. “He would say that you could tell a non-St. Louisan because [they] would let the solids settle in the water and drink the water off the top. A St. Louisan, if the water settled, they’d stir it around to get all that flavor, and they’d drink the water.

So, St. Louisans like their flavor.”

Our tap water is no longer delivered with complimentary Mississippi mud, but it still wins nationwide honors for flavor. A 2007 U.S. Conference of Mayors blind taste test placed St. Louis water at the top of its class, and the Pur water filter company recently gave it similar kudos. Our tap water is no longer delivered with complimentary Mississippi mud, but it still wins nationwide honors for flavor. A 2007 U.S. Conference of Mayors blind taste test placed St. Louis water at the top of its class, and the Pur water filter company recently gave it similar kudos.

The St. Louis Water Department produces 100-150 million gallons of clean water each day in a series of treatments that removes solids, kills bacteria, reduces industrial and agricultural chemicals and then softens it — which also minimizes lead.