Many First Nations communities do not have access to safe drinking water because of a "discriminatory legal gap" in Canada, according to the new report from Human Rights Watch, titled "Make It Safe: Canada's Obligation to End the First Nations Water Crisis."

According to the report released Tuesday, there are 133 unsafe water advisories in effect at 89 First Nations reserves in Canada, but many of those issues have gone unaddressed for decades because of low water-quality safeguards. Many residents are forced to boil their water, while others have relied on bottled water for decades. The lack of access to clean water has also created a number of health challenges for affected communities, according to the report.

"It's really hard to understand how it's continued for decades," Amanda Klasing, a senior researcher at Human Rights Watch, told CTV News Channel on Tuesday. Klasing said the federal and provincial governments of Canada have invested billions to address water safety issues on reserves, but funding has been inconsistent and insufficient.

She also pointed out that First Nations reserve residents "live under a different legal regime," which does not include the same legal safeguards for drinking water that exist in other parts of Canada. "It's concerning," she said.

"While off-reserve communities benefit from binding water quality regulations, there are no enforceable water regulations on reserves," the report says.

Human Rights Watch says there are a number of contaminants in the water supplies of some First Nations communities, including coliform, E. coli, Trihalomethanes and uranium.

The report found that insufficient access to clean drinking water had a significant impact on hygiene, because caregivers are forced to be stingy about how often they bathe their children in clean water.

"It's a daily indignity that caregivers have to deal with," Klasing said, adding that many skin issues can arise because people are bathing less frequently. Eczema and psoriasis are among the more common skin conditions experienced by First Nations reserve residents, the report says.

Klasing also pointed out that unsafe water can lead to overcrowding and a lack of growth in First Nations communities, because a proper water supply cannot be secured for new homes.

Human Rights Watch developed its report based on government water system data, 111 qualitative interviews and a survey of 99 households on five First Nations communities in Ontario.