Lead Testing in Well Water: California Guidelines & Safety

Lead contamination is a serious health concern, especially for children and pregnant women. Unlike public water systems that are regulated, private well owners are responsible for testing and treatment. The good news: lead rarely comes from the well itself—it usually enters water from household plumbing, which means the problem is identifiable and fixable.

This guide covers California-specific guidelines, who should test, how to collect samples properly, interpreting results, and what to do if lead is found.

Understanding Lead in Water

Health Effects

Lead is a neurotoxin with no safe level of exposure. Effects include:

• Children: Developmental delays, learning difficulties, behavior problems, lower IQ
• Adults: Cardiovascular effects, decreased kidney function, reproductive problems
• Pregnant women: Risk to fetal development, premature birth

Lead accumulates in the body over time. Even low-level exposure is concerning, particularly for children under 6.

Where Lead Comes From

Lead rarely exists naturally in groundwater. The source is almost always the delivery system:

• Lead service lines: Some older homes (pre-1950s) have lead pipes
• Lead solder: Used on copper pipe joints until banned in 1986
• Brass fixtures: Older brass contains up to 8% lead (now limited to 0.25%)
• Galvanized pipes: Can accumulate lead from other sources

Why Corrosive Water Matters

Water chemistry affects lead leaching:

• Low pH (acidic) water is more corrosive
• Low mineral content increases corrosivity
• Corrosive water dissolves more lead from plumbing

If your water is corrosive (common with some well water), even small amounts of lead in plumbing can become significant.

California Standards and Guidelines

Key Levels

Private Well Owner Responsibility

California doesn't require private well testing, but you should:

• Test voluntarily, especially with risk factors
• Address any detection above California's PHG (0.2 ppb)
• Take immediate action if above 15 ppb

Real Estate Transactions

California law requires disclosure of known well water contamination. Lead testing is increasingly common in home inspections, especially for older properties.

Who Should Test for Lead

High Priority

Test immediately if any of these apply:

• Home built before 1986 (when lead solder was banned)
• Young children (under 6) or pregnant women in household
• Visible corrosion on pipes or fixtures
• Never tested before
• Unknown plumbing history

Recommended Testing

• Any home built before 1990
• After any plumbing work or repairs
• When moving to a new property
• If water quality changes

Lower Risk (But Still Valuable)

• New construction with certified lead-free plumbing
• Plastic/PEX plumbing throughout
• Recent comprehensive testing showed no lead

How to Test for Lead

Use a Certified Laboratory

Important: Home test kits are not reliable for lead at health-relevant levels. Use a California-certified laboratory.

Find certified labs at: California Water Boards ELAP Program

Collecting the Sample

Proper collection is critical. Labs typically want a "first draw" sample:

1. Let water sit: Don't use the faucet for at least 6 hours (overnight works well)
2. Collect first water: Use the lab-provided bottle to collect the first 250-1000ml from the tap
3. Don't pre-run water: The point is to test water that's been sitting in pipes
4. Test at problem faucets: Kitchen, bathroom—wherever drinking water comes from

Some labs also request:

• Flushed sample (after running water 2-3 minutes) to compare
• Multiple locations to identify source

Cost and Timing

• Lead-only test: $20-50
• Lead + copper: $30-60
• Comprehensive metals panel: $100-200
• Results: Usually 5-10 business days

Free or Low-Cost Testing

Check for programs in your area:

• California WIC programs sometimes offer free testing
• Some counties have lead testing assistance
• Health departments may provide resources

Interpreting Results

Understanding the Report

Results are typically reported in:

• ppb (parts per billion) — most common
• µg/L (micrograms per liter) — equivalent to ppb

What Your Results Mean

First Draw vs. Flushed Sample

• High first draw, low flushed: Problem is in household plumbing
• Both high: Problem may be further back (service line or well-related)
• Only flushed high: Unusual; may need investigation

If Lead Is Detected

Immediate Steps (If >15 ppb)

1. Stop using tap water for drinking and cooking
2. Use bottled water or certified filtered water
3. Don't boil—this concentrates lead
4. Contact your healthcare provider for children/pregnant women

Identify the Source

Work with a plumber or water professional to:

• Inspect visible plumbing
• Test at different locations to narrow source
• Check fixture components

Treatment Options

Point-of-use filters (immediate):

• Reverse osmosis systems remove lead effectively
• Certified carbon filters (look for NSF/ANSI 53 certification for lead)
• Must be maintained properly

Plumbing remediation (permanent):

• Replace lead service lines
• Replace fixtures containing lead
• Re-pipe with lead-free materials

Corrosion control:

• Raise pH if water is acidic
• Calcite filters add minerals and reduce corrosivity
• May reduce but not eliminate lead leaching

Flushing (Temporary Measure)

Running water before use reduces lead:

• Run cold water 30 seconds to 2+ minutes before drinking
• Only works temporarily; not a permanent solution
• Wastes water

We use Hach and LaMotte professional water testing equipment for field analysis, with comprehensive lab testing through certified California laboratories.

Frequently Asked Questions