City officials are reassuring residents that a chemical spill in West Virginia that is making its way down the Ohio River will have no impact on local drinking water.

Mike McFadden, manager of the wastewater treatment plant, said the city does not have any intake valves in the river.

"We're on groundwater aquifers, so we're in great shape," he said. There is no chance for of the contamination to reach drinking water supplies and officials are not worried.

Concern has risen as contaminated water from West Virginia makes its way down the Ohio River toward Madison.

The water crisis started Jan. 9 when a chemical used in coal processing leaked from a Freedom Industries plant in West Virginia into the nearby Elk River.

Complaints came in to West Virginia American Water about the odor and officials discovered the source was the chemical 4-methylcyclohexane methanol, which spilled out of a 40,000-gallon tank.

The contaminated water will likely reach Madison sometime between today and late Thursday.

Larger cities are taking extra precautions. Cincinnati plans to shut down intake valves along the Ohio River to protect the city's drinking water.

Cincinnati Mayor John Cranley announced Monday that the valves will be shut down for at least 20 hours beginning tonight. Cranley says that will allow the water to pass the city without any chemicals entering the drinking supply.

The city plans to use a reserve of 60 hours of treated water, built up specially following the spill.

By the time the water reaches Louisville, it is expected to have become so diluted that it would no longer be a concern.

West Virginia officials believe about 7,500 gallons leaked from the tank. Some of the chemical was contained before flowing into the river and it's not clear exactly how much entered the water supply.

Federal authorities, including the U.S. Chemical Safety Board, have opened an investigation.

Only 14 people exposed to the contaminated water were admitted to the hospital, and none were in serious condition. No fish kills were reported and there was no effect on aquatic life or wildlife, state officials said.

The chemical, even in its most concentrated form, isn't deadly. However, people were told they shouldn't even wash their clothes in affected water, as the compound can cause symptoms ranging from skin irritation and rashes to vomiting and diarrhea.

Company president Gary Southern said Friday night that the leak had been stopped, but otherwise company officials have declined to comment.

Over the past few days, tests have showed that levels were consistently below a toxic threshold, and in some samples, there was no trace of the chemical at all.

By Tuesday morning, officials had given the green light to about 35 percent of West Virginia American Water's customers. Thursday's spill affected 100,000 customers in a nine-county area, or about 300,000 people in all.

The water crisis shuttered schools, restaurants and day-care centers, and truckloads of water had to be brought in from out of state. People were told to use the water only to flush their toilets. Hospitals were flushing out systems as were schools, which hoped to open again Wednesday.

It could still be days before everyone in the Charleston metropolitan area is cleared to use water, though officials say the water in certain designated areas was safe to drink and wash with as long as people flushed out their systems. They cautioned that the water may still have a slight licorice-type odor, raising the anxieties of some who believed it was still contaminated.

"I wouldn't drink it for a while. I'm skeptical about it," said Wanda Blake, a cashier in the electronics section of a Charleston Kmart who fears she was exposed to the tainted water before she got word of the spill. "I know I've ingested it."

In downtown Charleston, the first section of the city where water was declared safe, few signs of the crisis were visible late Monday and hotel guests were informed they could use everything but the ice machines.

But many businesses remained shuttered in outlying residential neighborhoods.