Suez has begun to adjust the acidity of its water and increase the amount of an anti-corrosion chemical, in the company’s latest effort to lower the amount of lead leaching into some Bergen and Hudson county residents’ drinking water.

It is the first time the company has changed the chemistry of its water since lead levels shot up to 18.3 parts per billion in the second half of 2018, exceeding the U.S. Environmental Protection Agency’s 15-parts-per-billion threshold for action.