JACKSON, Miss. (AP) — “Layers of inadequate oversight and enforcement” by state and federal agencies contributed to a water crisis in Mississippi’s capital city that left tens of thousands of people without safe drinking water for weeks in 2021 and 2022, a watchdog agency says.

The Mississippi State Department of Health did not consistently document deficiencies in the Jackson water system or notify city officials about significant problems after the department conducted sanitary surveys and annual inspections from 2015 through 2021, the U.S. Environmental Protection Agency’s Office of Inspector General said in a report issued Monday.

“The MSDH oversight failures obscured Jackson’s long-standing challenges, allowed issues to compound over time, and contributed to the system’s eventual failure,” said the inspector general, an independent group inside the EPA that began investigating Jackson’s water woes in September 2022.

Because of those shortfalls, the EPA did not know the extent of management and operational issues until it inspected the Jackson system in February 2020, the inspector general added.

State health department officials will respond to the inspector general’s report after they’ve finished reviewing it, spokesperson Greg Flynn told The Associated Press on Wednesday.

About 25% of Jackson residents live in poverty, and the city struggled for years with water quality problems and understaffing at its water treatment plants.

In early 2021, a cold snap froze equipment at a Jackson water treatment plant, and thousands of people went weeks with low pressure or no running water at all. People collected water in buckets from distribution sites to flush toilets and bathe, and the National Guard helped distribute drinking water.

In January 2022, the EPA issued a notice that Jackson’s water system violated the federal Safe Drinking Water Act. The system nearly collapsed in August and September 2022 after heavy rains exacerbated problems at a treatment plant, leaving tens of thousands of people without water for drinking, bathing, cooking or flushing.

The EPA’s National Enforcement Investigations Center found that Jackson’s system issued more than 750 boil-water notices from 2016 through 2020. Customers are told to boil water because bacteria or other contaminants can enter the system after pipes break or the distribution system fails.

The center also found that Jackson had more than 7,300 breaks in water distribution pipes from 2017 through 2021. The report said those occurred at an average annual rate of 55 breaks per 100 miles (161 kilometers) of pipe, “significantly higher than the industry benchmark” of no more than 15 breaks per 100 miles of line per year.

The inspector general’s report said that according to a former interim director for Jackson’s Department of Public Works, one distribution pipe had been broken since 2016 and leaked 4 million to 5 million gallons (15.1 million to 18.9 million liters) of water per day — enough to fill five to nearly eight Olympic-sized swimming pools daily. That translated to a loss of about 10 billion to 13 billion gallons (37.9 billion to 49.2 billion liters) between 2016 and 2022, the report said.

In addition to problems with water pressure, Jackson has also had water quality problems for years. Because of concerns about lead levels, the city has told people to avoid using hot tap water for drinking or cooking and to only use filtered or bottled water for baby formula.

In late 2022, a federal judge put an independent administrator in charge of the Jackson water system.