Hot tubs for rooftops in Chicago? No tanks

CHICAGO — After the Chicago Fire of 1871, rooftop industrial water tanks became a hallmark of factories, warehouses and tenements. As electrical sprinkler systems and modern plumbing have been installed in most buildings, the rooftop tanks are seen as obsolete, and fewer than 100 are in use here today.

But the stocky tanks are a beloved part of the skyline for many Chicagoans, and recently the City Council passed an ordinance calling for the tanks' preservation.

City officials have completed a census of the tanks and held an architectural competition to design alternative uses for defunct tanks. Suggestions included turning the tanks into rainwater-collection systems, urban gardens and hot tubs.

But Ronald Carlson, the sole remaining employee of Johnson & Carlson Tank Sales and Service, wants to see the tanks doing their original job. He notes that electric sprinklers could be compromised by a blackout. Not so with the tanks, which rely solely on gravity. And he finds some of the other suggestions impractical.

Especially the hot tub.

"Most of these tanks sit on top of the building's roof, usually on a 35- to 40-foot tower," said Carlson, whose great-grandfather was a co-founder of the company. "If people are up there partying and drinking, once they get done, they have to climb down the ladder. You know what will happen sooner or later."