Water softeners and filtration in Mercer County

Local findings

• Trenton Water Works under state oversight

  In October 2022, NJDEP ordered Trenton Water Works to fix how it operates and maintains its system, and has overseen it directly since. The utility has repeated past violations for disinfection byproducts (TTHM and HAA5).

  Source: NJDEP: Trenton Water Works oversight

Across the region

• Arsenic in private wells

  New Jersey's Piedmont region has the state's highest rate of arsenic in private wells: about 17% exceed the state standard. It comes naturally from minerals in the bedrock, and you can't see, taste, or smell it.

• Acidic, iron-prone well water

  This area sits on the sandy aquifers of the Coastal Plain. Water in the widely used Kirkwood-Cohansey aquifer is naturally acidic, which can corrode pipes and leave blue-green stains, and some aquifers here carry a lot of iron. USGS testing also found radium above the federal limit in about a third of sampled Kirkwood-Cohansey wells in southern New Jersey.

• PFAS limits

  New Jersey was the first state to set limits for PFAS "forever chemicals": 14 parts per trillion for PFOA and 13 for PFOS and PFNA. Public utilities must meet them. Private wells are only tested when a home is sold or leased.

• Hardness varies by town

  New Jersey's median tap water is moderately hard, about 5 grains per gallon, and it changes a lot from one supplier to the next. Your water test tells you exactly where you stand.