Most water systems in New Jersey are subject to the Federal Lead and Copper Rule which contains extensive monitoring and treatment regulations that require water systems to provide water which is less corrosive to lead plumbing.
Under the Federal Lead and Copper Rule, public community and non-transient, non-community water systems are required to take samples at drinking water taps, such as kitchen and bathroom taps, throughout their distribution systems in specific areas deemed most vulnerable to lead based on their current record of piping and plumbing materials. These sample sites must be prioritized by use (e.g., residence) and are most likely to have higher probability of lead leaching into the drinking water (e.g., single family residences with lead service lines). If in a monitoring period, the 90th percentile of lead samples collected is greater than 15 parts per billion (ppb), then the water system would incur what is called an “Action Level Exceedance” (ALE). While this is not strictly a violation, it does provide an indicator that the water provided by the public water system may be corrosive, and thus, triggers a number of follow-up steps. These steps may include an increased frequency of monitoring, public education, replacement of lead service lines, and/or evaluating and implementing corrosion control treatment among others. The water system returns to compliance following the completion of the required steps and when the 90th percentile for lead is below 15 ppb for two consecutive monitoring periods. Copper in drinking water is also regulated using an ALE as a marker for treatment issues; however, some of the steps that must be taken by water systems do vary from those required for lead.
Many water systems test for lead as a regular part of water monitoring. These tests give a system-wide picture and do not reflect conditions at a specific drinking water outlet such as a faucet or sink. If you are uncertain who your water supplier is, you can look it up on NJ Drinking Water Watch.