“Critical” concerns were raised about the legionella risk at council-owned shops in south Cumbria.
Risk assessments were carried out at 19 premises leased from Barrow Borough Council at Newbarns, Ormsgill, Walney and Dalton.
The bacteria, which can be found in water systems and inhaled in droplets, can be fatal.
Repairs have been carried out at the affected properties, none of which have been identified by the authority.
Experts from a water treatment firm found no premises had the “highest” level of concern for legionella, according to a report prepared for the council.
However, “critical” and “essential” issues were discovered that needed addressing promptly to guard against the bug taking root and to comply with safe practice.