CALAIS – Higher levels of bacteria, yeast or mold were detected in the city’s water supply last week, and the city’s engineer suggested further tests be conducted.

On Friday, the Maine Drinking Water Program and the Maine Rural Water Association were consulted, and neither E coli nor fecal coliform was found in the water, so a boil order was not needed.

But the city did learn that that a “common background bacteria” may be causing the “swamp water” smell that some residents in the city have experienced, City Manager Linda Pagels said Friday. More chlorine is being added to the water to knock down the sulfur-producing bacteria.

“The system will also be bled during this time to increase flows in the pipes. Customers of the water system may experience ‘red water’ from the leaching of iron pipes caused by chlorine, and-or a bleach smell,” Pagels said.

More tests will be performed Tuesday, and the entire water system will be flushed in upcoming weeks. Also on Tuesday, water users have been invited to attend a meeting with the state Public Utilities Commission to discuss water quality issues and the proposed 41 percent rate hike. The meeting will be at 8:30 a.m. at the Washington County Community College.

A petition was submitted to the PUC that asked for an investigation of the proposed rate hike.

In the past, Calais bought its water from neighboring St. Stephen, New Brunswick. A change in U.S. water standards forced the city to look elsewhere for its supply.

Two years ago, the city drilled wells and last year turned on the tap. Because in some instances the water flowed in an opposition direction from its former flow for the first time in more than 100 years, sediment was dislodged and caused other water problems.

Calais is not the only community concerned about a water rate hike. In Eastport, some residents also are wondering about a hike proposed by the Passamaquoddy Water District. A meeting is scheduled at 1 p.m. today at the Pleasant Point Tribal Court.