The 10 ppb Lead Rule: Which Water Systems It Changes in 2027

What changes

The Lead and Copper Rule Improvements, finalized in 2024, lower the lead action level from 15 ppb to 10 ppb when compliance begins in November 2027. They also require utilities to replace lead service lines - generally within ten years - and to sample from homes with lead lines first.

Who is in the band

Right now 552 systems are over 15 ppb, serving about 1,048,730 people. Another 650 systems are over 10 but at or under 15 - legal today, over the line in 2027. They serve about 3,565,898 people, more than 3 times as many as the systems over the current limit. The largest of them: Metropolitan Utilities District, NE (12.3 ppb), Modesto, City Of, CA (12 ppb), Syracuse City, NY (12 ppb), Veolia Water New York, Inc. Rd-1, NY (12.2 ppb), Olathe, City Of, KS (11 ppb).

What it means for your house

Nothing in your pipes changes on the date. What changes is what your utility must do: public notice, corrosion-control work and more sampling once it is over 10. If your system is in that band, test your tap now rather than waiting for the rule to say so - the water is the same water either side of the deadline.

Where to go next

See the range across large systems: Aurora, IL, Metropolitan Utilities District, NE, Washington Suburban Sanitary Commission, MD.

Why Small Water Systems Go Over the Lead Limit More Often · Over the Lead Limit Before, Under It Now: What That Means