The city of Eagle Lake, Minn. — just east of Mankato — is asking residents and businesses to boil water from the municipal water system.

Officials said a power outage on Monday — combined with the fact the city’s water tower is offline for maintenance — led to a drop in pressure in the city’s water system. That means there’s the potential there could have been groundwater intrusion and contamination in the city water lines.

“Once power was restored, the city increased chlorine feed, flushed the distribution system, and is testing for total coliform bacteria and chlorine residual. Testing takes 24 hours. We anticipate receiving test results on Wednesday,” the city of Eagle Lake posted in an online update on Tuesday morning. “As soon as the test results indicate that our water is safe, the boil water advisory will be lifted and an announcement made.”

In the meantime, the city said residents and businesses should boil water they use for cooking or food preparation for at least one minute, or use bottled water.

The city said that residents may notice rusty or brown water for a brief time as the system regains pressure, similar to what happens when fire hydrants are flushed for maintenance. Once the boil water advisory is lifted, the city recommended that residents let the water run for a while to flush the service lines.