LCR vs LCRR vs LCRI

The LCR (1991), LCRR (2020), and LCRI (2024) are three successive EPA rules that govern how water systems sample for lead, report results to customers, and replace lead service lines — each tightening requirements the previous version left incomplete.

All three rules live at 40 CFR Part 141 Subpart I.

Timeline

| Rule | Full name | Year promulgated | FR citation | Action level | Sampling protocol | LSL replacement schedule | Inventory required | |------|-----------|-----------------|-------------|--------------|-------------------|-------------------------|--------------------| | LCR | Lead and Copper Rule | 1991 | 56 FR 26460 | 15 µg/L | First-liter (1st draw) | None mandated | None | | LCRR | Lead and Copper Rule Revisions | 2020 | 86 FR 4198 | 15 µg/L | First-liter (1st draw) | No fixed schedule | Yes — initial inventory due Oct 16, 2024 | | LCRI | Lead and Copper Rule Improvements | 2024 | 89 FR 86416 | 10 µg/L | Paired 1st- and 5th-liter; use the higher value | 10 years (full replacement by Nov 1, 2037) | Yes — LCRR inventory deadline preserved |

Why the rules keep changing

The 1991 LCR established the basic framework: sample tap water at high-risk homes, calculate a 90th-percentile result, and act if it exceeds 15 µg/L. That action level held for 30 years. What it did not do was require utilities to know where their lead service lines actually were, or to replace them on any timeline.

The 2020 LCRR filled the inventory gap. Systems had to survey their distribution networks and submit an initial service-line inventory to their state primacy agency. The compliance deadline was set at October 16, 2024. The action level stayed at 15 µg/L.

The 2024 LCRI went further on two fronts. First, it lowered the action level to 10 µg/L, recognizing that no level of lead exposure is safe and that the 15 µg/L threshold was never a health standard. Second, it mandated a 10-year full replacement schedule for all lead and galvanized-requiring-replacement (GRR) service lines under utility control. It also tightened the sampling protocol: systems at lead service line sites must now collect paired first- and fifth-liter samples and use whichever value is higher for compliance purposes. The single first-draw sample the LCR used could miss lead that flushes into the line between sampling events.

Where you are right now (2026)

Two deadlines have already passed, and one is approaching.

The LCRR initial service-line inventory was due October 16, 2024. If your system filed by that date, the LCRI preserves that inventory — you do not refile. If your system missed the deadline, it remains overdue; the LCRI did not reset the clock.

The LCRI was finalized on October 30, 2024 and carries a compliance date of November 1, 2027. That is when the lower 10 µg/L action level takes effect, the paired sampling protocol becomes mandatory, and the 10-year replacement clock starts. Systems that are already replacing lead service lines under LCRR's voluntary timeline get credit toward the LCRI replacement schedule.

Between now and November 2027, most systems are in a planning window: inventories should be complete, replacement prioritization should be underway, and sampling programs should be evaluated against the new paired-sample protocol before it becomes mandatory.

For a detailed compliance calendar, see LCRI 2027: What water systems need to do.

Related terms

Citations