FLINT, MI -- Lead levels in the city's most at-risk homes have been below the federal action level for two straight years, including the first six months of 2018, the state Department of Environmental Quality says.

Lead and Copper Rule testing in Flint from Jan. 1 to June 30 showed 90 percent of samples at or below 6 parts per billion of lead, well below the federal threshold of 15 ppb.

The numbers released Wednesday, July 18, match preliminary water testing results from the first half of this year, which also registered 6 ppb and which state officials had announced last month.

"Two years of LCR data show that Flint's water is testing the same as or better than similar cities across the state," the DEQ announcement Wednesday says. "Third-party independent experts have also confirmed that Flint's water currently tests below actionable levels for lead and copper.

"To help ensure the city's water quality is maintained, residents are encouraged to use their water to keep fresh water flowing through the distribution system."

MLive-The Flint Journal could not immediately reach a city spokeswoman for comment on the lead and copper test results.

Just last month, the city agreed to take back greater responsibility for LCR testing after the state said preliminary results from the first six months of this year also registered a 90th percentile for lead of 6 ppb.

The state has been involved in the testing of water here since 2016, soon after state and federal recognition of the Flint water crisis.

Flint suspended its water testing in the second half of 2015 after officials acknowledged having filed false reports previously, certifying that they were targeting high-risk homes with their sampling -- something later revealed not to be true.

Since that time, the 90th percentile for lead has gone from 20 ppb from January through June 2016 to 12 ppb in the second half of that year. During the first six months of 2017, the 90th percentile dropped to 7 ppb, and has registered 6 ppb during the last half of 2017 and first half of 2018, according to state records.

The level of lead in Flint water started to increase immediately after the city's water source was changed to the Flint River while the city was being run by an emergency manager in April 2014.

Even though testing was flawed, the 90th percentile for lead rose to 11 ppb by 2015, at the time the highest result for Flint water since regulations for lead in water began in 1992.