Approximately 400,000 people are without water after a do not use water advisory was issued Saturday for Toledo and parts of Monroe County.
Several more tests at the state and national level have been conducted and show the water is safe, but Toledo tests are inconclusive.
The mayor of Toledo expects to have an update on the situation by 4 p.m. Monday.
Meanwhile, residents who receive water from the city of Toledo should not drink or boil the water. The water should not be used for brushing teeth or preparing food. Healthy adults can shower with the water, but children or adults with immune system deficiencies should avoid exposure to the toxins in the water.
Officials said blue-green algae that's piling up near a water intake in Lake Erie is causing the contamination.
The Monroe County communities that are affected by the Toledo water advisory are Bedford Township, Erie Township, La Salle Township and Luna Pier. All other Monroe counties have different water systems.
Eighteen-month-old Hunter is drinking bottled water instead of using his favorite sippy cup. His mother said it's been hard to give Hunter a bath and keep him away from the water.
With no way of knowing how long the water ban will stay in place, store shelves in Monroe were empty as panicked families stocked up.
Harmful algae bloom build-up in Lake Erie contaminated the Toledo water system. HABs can produce toxins that can make people and animals sick with exposure.
The water at Toledo's Collins Park Water Treatment Plant showed an excess of microcystin around 1 a.m. Saturday during two tests. But Monroe emergency management only found out six hours later after a central dispatch worker happened to see it on the news.
Those affected should not drink or boil the water until an all-clear notice is issued.
Officials said water that comes from Lake Huron and the river is safe. Water that flows from Lake Michigan also passed quality testing Sunday afternoon.
The University of Toledo, Toledo Zoo, many restaurants and other businesses were shut down on Saturday due to the advisory.
Anyone unable to leave their home and is in need of water should call 734-243-8600. Red Cross volunteers will be available to deliver water to those who are unable to get to the filling stations themselves. Phone lines will be open until 8 p.m. Sunday.