More than 400,000 people who get their water from Lake Erie were told to keep the taps off, Sunday. A growing number of algae blooms have turned the water into a pea soup color, leaving behind toxins that can sicken people and kill pets.
The dire situation in Toledo, Ohio led to extra testing of Chicago's water in Lake Michigan.
Officials said Sunday Lake Michigan is in the clear.
The Chicago Department of Water Management tested the water in Lake Michigan.
They took samples from the water Saturday night and sent them to Indiana for testing.
The department says those tests came back negative for the toxin microcystic LR, the toxin found in Lake Erie.
Jennifer Caddick with the Alliance for the Great Lakes said this is something advocates have been warning communities about for some time.
"The lion share really comes from runoff on farm fields and sewage treatment plants. Those are the two areas that we really need to be paying attention and start implementing programs to keep nutrients on our land and not in our waterways where they cause problems like what we're seeing in Lake Erie," said Caddick.
City officials add Lake Michigan is regularly tested for blue green algae 2 to 3 times a week. Chicago tap water is safe to drink and use.
That hasn't been the case for Toledo, Ohio's 4th largest city.
It's residents both in Ohio and southern Michigan were being instructed not to drink the water, take showers or attempt to boil it.
Drinking the water can cause vomiting, cramps and rashes.
Toledo's Mayor said Sunday tests have shown decreased level of the toxins in the water.
"This is not going to be our new normal. We're going to fix this. And our city is not going to be abandoned," said D. Michael Collins.
Advocates said the nightmare situation in Toledo is uncharted territory.
"Toledo is certainly going to be a really important case for all other communities to look at and understand how we can improve our treatment systems. But, we also know they are doing their very best that they can do restart the water supply," added Caddick.
The Chicago Department of Water Management said it will continue to monitor the Toledo situation and will continue to do routine testing for blue green algae.