It has been almost four years since residents of Flint, Michigan, first started reporting a strange color and smell to their water. Since then, its water has gotten much clearer. But while much of the public attention has long moved on, it’s worth remembering that Flint is still not in the clear.

As the Flint Journal reported Monday, a round of water testing in February by the Michigan Department of Environmental Quality found 28 water samples in elementary schools that registered above 15 parts per billion of lead, the threshold under the Lead and Copper Rule.

While the Journal was clear that though the numbers are elevated over the previous month—that test found 20 samples above 15 ppb—they don’t necessarily mean the amount of lead in school water has spiked, as the testing methods and conditions have changed. The assistant director of the Department of Environmental Equality’s Office of Drinking Water and Municipal Assistance described the results as “encouraging” because “they meet federal guidelines for lead if treated like samples collected by municipal water systems.”

The state is still providing bottled water for residents and is planning to continue to do so until all affected service lines are replaced.

There is no level of lead exposure considered conclusively safe.