A salmonella outbreak has forced Alamosa, Colo., officials to conduct an extreme treatment of its water system. On Tuesday, the city flushed its pipes with concentrations of chlorine so high that residents were urged not to even touch the water flowing from their taps.

More than 200 cases of salmonella have been reported in the city, though the source had not yet been identified, according to the Colorado Department of Public Health and Environment. The city warned all residents who receive city water to drink bottled water instead, and arranged for volunteers to deliver water to the elderly and disabled.

The chlorine flush was done in three stages, and residents were told that during the first stage the water could cause skin, eye and other irritation on contact. "During Stage 1, do NOT use city water for anything other than flushing toilets," city officials said in a press release. The city's water was expected to stay at Stage 2 — with chlorine levels slightly above those found in properly maintained swimming pools and therefore unfit for drinking but possibly safe for bathing — for 10 days.