Thirteen Michigan water systems failed to meet federal standards for lead in drinking water in the last half of 2018, and seven of those systems had lead levels at least twice as high as the state will allow starting in 2025.

Data requested by MLive-The Flint Journal from the Michigan Department of Environmental Quality shows water systems above that action limit in the most recent Lead and Copper Rule testing are located throughout the state and are both large and small -- one serving less than 100 homes and others providing water to cities as large as Hamtramck and Benton Harbor.

A total of 27 water providers registered 90th percentile lead levels of at least 13 parts per billion, beyond the 12 ppb future threshold established last year by the state.

The 90th percentile is a formula used by the U.S. Environmental Protection Agency to measure the prevalence of lead in water sampled by the more than 1,200 public water systems in the state. Federal regulations set the lead limit at 15 ppb.

A water system with a 90th percentile for lead of 15 ppb for example would mean that 10 percent of high-risk homes tested had lead readings of 15 ppb or more -- the level at which the Centers for Disease Control and Prevention says action should be taken.

The DEQ can require additional testing, changes in treatment for corrosion control or replacement of service lines that contain lead in response of readings that high.

In the Melrose-Chandler Water system in Charlevoix County, testing was repeated after one sample produced a very high lead level, said Walter Breidenstein, manager of the system that serves a single subdivision.

Because Melrose-Chandler serves just a few hundred people, it was only required to collect five samples from July until December 2018, and one sample -- collected from a rarely used basement sink -- was enough to put the system’s 90th percentile for lead at 25 ppb, Breidenstein said.

State records show that in the first six months of last year, the same system’s 90th percentile was just 2 ppb.

“We think it’s just a fluke thing because we’ve never had the problem,” Breidenstein said. “We were all freaked out” until residents learned that stagnant water from a single tap may have caused the jump. He said subsequent tests in the same home and elsewhere in the system have turned up clear since.

Lead can enter drinking water when service lines that contain lead corrode, especially where the water has high acidity or low mineral content that corrodes pipes and fixtures, according to the EPA. The most common problem in homes is the result of brass or chrome-plated brass faucets and fixtures with lead solder, from which significant amounts of lead can enter into the water, the agency says.

Another small water system registered the highest LCR test result in the state -- 48 ppb -- but a representative of the Hills of Walloon Association said the result was a historical deviation caused by sample from a single faucet that was rarely used in one home.

Fewer than 100 homes draw from the Hills of Walloon water system, according to state records, and the water -- drawn from deep wells -- registered a 90th percentile of just 6 ppb during the first six months of last year.

“The system was tested again in September” and was in compliance, said Thomas Saeli, president of the association. “Our water system doesn’t have lead (pipe) in it. It had an improper test (that) was done."

Other systems above 15 ppb of lead in the last half of last year are Maple Knoll in Eaton County (44), Lakeview Chalet Condominiums in Oakland County (43), Hermansville Housing Commission in Menominee County (29), the city of Hamtramck in Wayne County (28), the village of Lawrence in Van Buren County (24), Benton Harbor in Berrien County (22), Sims-Whitney Utilities Authority in Arenac County (20), Gun River Estates West in Allegan County (19), Country Living Adult Foster Care in Hillsdale County (16), Kellogg Biological Station in Kalamazoo County (16) and the city of Parchment in Kalamazoo County (16).

MLive-The Flint Journal could not reach a representative of the DEQ for comment on the results or representatives of some water systems that surpassed the federal action limit for lead.

In October, residents of Benton Harbor and Hamtramck were notified about the discovery of high levels of lead in those municipal water systems, and Benton Harbor announced it would supply bottled water to homes that tested above 15 ppb.

Late last year, a health advisory was issued for lead in the city of Parchment’s water, and its 90th percentile was 16 ppb -- above the action level.

Officials there have said a protective coating inside pipes was scoured when the city purged its municipal water supply to remove traces of toxic per- and polyfluorinated substances, or PFAS, in July. Parchment connected to the city of Kalamazoo’s water system in August but lead has continued to leach into tap water from old lead service lines still in use.

Lead notices would also have been required in the village of Lawrence in Van Buren County, which registered a 90th percentile of 24 ppb. The village -- with a population of 1,045 -- supplies water from three wells through two water towers, according to its website.

In the Upper Peninsula’s Menominee County, the Hermansville Housing Commission last year provided notice of its lead levels to residents in 24 apartments and has been evaluating potential actions to lower lead levels. The agency’s water was above the federal action level in both the first and second half of 2018 -- the only water system in the state to do so.

Exposure to lead can cause behavior problems and learning disabilities in young children and can also affect the health of adults, according to the CDC, which says no safe blood level has been identified and all sources of lead exposure for children should be controlled or eliminated.

Awareness of the dangers of lead in water has increased since the Flint water crisis.

Flint’s most recent LCR testing showed a 90th percentile of just 4 ppb.