Title 22 Chapter 17.5: Lead and Copper — Quick Reference
Action Levels — Memorize These
| Contaminant | Action Level | DLR |
|---|---|---|
| Lead | 0.015 mg/L | 0.005 mg/L |
| Copper | 1.3 mg/L | 0.050 mg/L |
These are action levels, not MCLs. That distinction matters. An action level exceedance triggers a response sequence. It does not automatically mean the water is unsafe to drink.
LCRI update (compliance November 1, 2027): The federal Lead and Copper Rule Improvements (LCRI), finalized October 2024, lowers the lead action level from 0.015 mg/L to 0.010 mg/L. The copper action level remains 1.3 mg/L. California will implement the LCRI starting November 2027. For the T-5 exam, know the current Title 22 action levels (0.015/1.3), but be aware the lead action level is changing. Water systems keep their current tap sampling plans until LCRI compliance begins.
System Size Categories
| Category | Population |
|---|---|
| Large | >50,000 persons |
| Medium | >3,300 to 50,000 |
| Small | 3,300 or fewer |
The 90th Percentile Calculation
- Rank all tap sample results from lowest to highest
- Multiply total number of samples by 0.9
- The value at that position is the 90th percentile
- If 90th percentile is GREATER THAN the action level, the system has an exceedance
Special case: systems with 100 or fewer persons collecting 5 samples use the average of the highest and second-highest results. Results below 0.001 mg/L are treated as zero.
Tap Sampling Requirements
First-draw samples: 1-liter from taps with lead plumbing or lead solder, after standing time of 6 hours minimum. The standing time requirement is what makes these “first-draw” samples, and the exam will test whether you know it.
LCRI update: The LCRI changes tap sampling protocol to require both first-liter and fifth-liter samples at sites with lead service lines. The higher of the two values will be used for compliance. This dual-sample protocol replaces the current first-draw-only method starting November 2027.
Response Sequence When Action Level Is Exceeded
This is a defined sequence, not a menu of options:
- Corrosion Control Treatment (CCT) — Study, recommend optimal treatment, install, demonstrate optimization, operate within approved WQP ranges
- Source Water Treatment — Required if action level still exceeded after CCT optimization
- Lead Service Line Replacement — Required if action level still exceeded after CCT and source water treatment
- Public Education — Required whenever lead action level is exceeded. Mandatory content covering health effects, sources of lead, and consumer actions (flushing, using cold water)
LCRI update: The LCRI mandates complete replacement of ALL lead and galvanized-requiring-replacement service lines within 10 years of the November 2027 compliance date, regardless of current lead levels. This is no longer contingent on action level exceedance. The 10-year replacement mandate applies to all systems with lead service lines.
Water Quality Parameters (WQPs)
Monitored to track CCT effectiveness: pH, alkalinity, temperature, calcium, conductivity, and orthophosphate or silica (if used as corrosion inhibitor). Frequency starts at every 6 months during initial monitoring, reduced after optimization is demonstrated.
What to Watch on the Exam
- Lead and copper use action levels, not MCLs. The exam tests this distinction directly. An MCL violation and an action level exceedance trigger different response requirements.
- The 90th percentile calculation is a common exam question. Practice it. Know that you rank low to high and multiply by 0.9.
- First-draw sampling requires 6 hours minimum standing time. If you see an exam question about sampling protocol and the standing time is less than 6 hours, the sample is invalid.
- Action level exceedance now triggers Tier 1 public notification (24 hours) under LCRR §141.202(a)(10), effective October 16, 2024. Older study materials may show Tier 2 (30 days).
- Consumer notice is separate from public notification. Individual tap results must be provided to each sampled customer regardless of whether the system exceeded the action level.
- Records must be retained for 12 years. That's longer than most other rules.
- The LCRI lowers the lead action level to 0.010 mg/L starting November 2027. For the current T-5 exam window, 0.015 mg/L is the action level in Title 22.
- Small systems may apply for reduced monitoring to once every 9 years if they are material-free and below the action level threshold.
Federal Rule Implemented
Lead and Copper Rule (40 CFR 141 Subpart I), with LCRR interim requirements in effect (including Tier 1 PN for lead ALE under §141.202(a)(10)) and LCRI compliance beginning November 1, 2027.