Water that runs from the taps at the Stillwater state prison is safe to drink, but the Department of Corrections should do something to address discoloration that could signal corroded pipes or other problems, the Minnesota Department of Health said Wednesday.

The health department conducted tests just over a week after more than 100 prisoners refused to return to their cells on Sept. 3, in protest of staff shortages that left them little access to showers and cool water during some of the hottest days of summer in the un-air-conditioned prison. Incarcerated and formerly incarcerated men have said the only water they could access, from faucets in their cells, was often brown during the summer and they used socks or other clothes to try to filter it.

"Every single one of us put socks on the faucet," Elizer Darris, an activist and former co-executive director of the Minnesota Freedom Fund said, recalling his incarceration at Stillwater during a rally earlier this month. "The water is brown. This is what we're drinking."

The health department took water samples from 81 sites in the prison, including faucets from a cell in every block, to test for bacteria, iron, manganese, lead, copper, suspended solids and chemicals. The water was found to be safe but sometimes discolored.

"The good news is that treated water coming into the facility and at all sampled locations meets federal Safe Drinking Water Act standards," MDH Assistant Commissioner Dan Huff said in a statement. "However, we did note some instances of discolored water, build-up of minerals from water on fixtures and iron staining on some sinks. We're recommending a series of actions for DOC that should help address these issues."

Discolored water "indicates enhanced building water management and increased plumbing maintenance or replacement is required," the report released this week said.

The health department recommended the Department of Corrections develop a water management plan for the Stillwater prison, clean fixtures and aerators, flush the whole system and hire a licensed plumber to inspect the facility.

Correction: An earlier version of this story incorrectly described Elizer Darris’ position with the Minnesota Freedom Fund.