Heavy rain and winter runoff in the month of May has affected more than people's homes along the Ottawa River.

The river itself, often polluted with sewage overflow after a day or two of heavy rain, has had to absorb more than 600-million litres over the past week alone, according to figures released by the City of Ottawa.

The city's water treatment facilities have been taxed to the limit, so combined sewer overflow — the combination of storm water and household sewage — has gone, untreated, into the river. Pipes built up until 1960 used to combine these two streams of sewage.

Not only is the river contaminated with additional fecal matter, houses affected by flooding are contaminated by the water. And because many of the houses are on well water, as opposed to city water, their drinking and showering supply gets contaminated, according to city officials.

The city says May 5 to May 7 was particularly bad — with over 430-million litres of sewage overflow.

Public health at risk

City manager Steve Kanellakos says it's important people take precautions for their own safety.

"We know the water is contaminated from upstream. We know the septic systems have failed. And so people are going to have to take extreme precautions as they're working in that environment. So they don't get (sick). And that's why public health has a huge role to play now as they go door-to-door," said Kanellakos.

A cottage on the Ottawa River, seen on May 8, 2017. People who rely on well water need to take extra precautions against contamination. (Laurie Fagan/CBC)

"One of the things we know is that the furniture that's in the house will be contaminated and they need to remove it, and they need to have guidance on what comes out. And some people have difficulty letting go of some of their possessions and we need to get things out of their house for their own safety," he said. "We're looking at doing portable showers, hand-washing stations, water delivery, all those things are being planned right now to be moved into the community."

According to Mayor Jim Watson, the city's solution to make the Ottawa River healthier, the Ottawa River Action Plan, is currently under construction.

"It's actually a very permanent solution. It's going to see 95 per cent of the pollutants not going into the river."

Reduced consumption is key

Giant underground holding tanks are being installed in order to contain the excess runoff from heavy rains, until the city's water treatment facilities can catch up, and treat the water before being released, said Watson.

But the amount of combined sewer overflow at the moment is much higher than the capacity of the holding tanks, so in theory, the difference would end up in the river untreated anyway.

The Ottawa Riverkeeper, Meredith Brown, said Ottawa isn't the only culprit. Cities along the river such as Gatineau also release untreated sewage.

And while Ottawa posts information about breaches to its sewer output online, municipalities such as Gatineau, and small communities, do not, she said.

The mayor of Clarence-Rockland, Guy Desjardins, said a public appeal to reduce water consumption during the heavy rainfall had an instant impact in his community and Ottawa residents can do the same.

"It's not a big request to the public. The public is always happy to cooperate. It's such an easy way to solve this problem. And everybody knows how it works. So, I'm sure the people of Ottawa would gladly cooperate in a problem like this and reduce their consumption to help the environment," said Desjardins.