Lead testing of drinking water

Short definition

Lead testing of drinking water is the lab or home-kit test that measures lead concentration at your tap. Pre-1986 homes (lead solder) and pre-1940 homes (potential lead service lines) are the WA risk profiles. The EPA action level is currently 15 ppb, lowering to 10 ppb under the Lead and Copper Rule Improvements (LCRI) in late 2027. Households with kids or pregnancy should target under 5 ppb.

What it is

Lead in drinking water comes from three sources in residential plumbing:

1. Lead solder at copper-pipe joints, used until banned by federal law in 1986.
2. Lead service lines between the city main and the house, common in pre-1940 housing in some WA cities (notably Tacoma’s Hilltop and similar pre-WWII areas).
3. Lead in brass fixtures — until 2014, “lead-free” brass was allowed up to 8% lead; the current rule (≤0.25%) effectively eliminates lead from new fixtures.

The amount of lead that leaches depends heavily on water chemistry. Soft acidic water (Cedar/Tolt source water in Seattle, many private wells in the Olympic Peninsula and Mason/Jefferson counties) is more aggressive on lead solder than hard alkaline water. Standing water in pipes overnight picks up more lead than running water — that’s why the standard test protocol is “first draw” after at least 6 hours of stagnation.

The test:

1. Home test kit — $20–$50 at hardware stores. Watersafe, First Alert, others. Semi-quantitative; useful for rough screening.
2. Lab test (gold standard) — $20–$100 per sample at WA-certified labs (Edge Analytical, Eurofins, others). Some WA utilities offer free or subsidized testing.
3. First-draw sample — collect after 6+ hours of stagnation (typically first thing in the morning); fill the lab-provided bottle from the cold-water tap at the kitchen sink.
4. After-flush sample — run cold water 1–2 minutes, then collect. Shows baseline contribution from utility-side line and deeper plumbing.

Compare results to the EPA action level:
– Current: 15 ppb.
– From late 2027 (LCRI): 10 ppb.
– For households with kids or pregnancy: target under 5 ppb.

Why it matters to a homeowner

If your home is pre-1986, lead solder is statistically likely somewhere in your plumbing. If your home is pre-1940 in a WA city with historical lead service lines, the service line is also a possible source. Testing is the only way to know your actual exposure.

The good news: most lead exposure is mitigatable without major plumbing work. The standard mitigation steps:

1. Run cold water 30 seconds before drinking after long stagnation (overnight, after vacation).
2. Use cold water for cooking and drinking only — heat increases lead leaching.
3. Install RO at point of use for drinking water — RO removes lead.
4. Install certified lead-removal filter (NSF/ANSI 53 standard) — POU at kitchen.
5. For severe cases, repipe — galvanized or lead-soldered copper to PEX.
6. For lead service lines — contact your utility about replacement programs (Tacoma has historically run such a program; verify current status).

When a plumber recommends a “whole-house repipe to PEX” specifically for lead, that’s a serious project — $4,000–$15,000 in WA depending on house size and access. For most homes, POU RO at the kitchen sink is the high-leverage first step. Confirm with a post-install lab test that the RO is doing its job.

Common failure modes (of testing)

• Test taken after water has been running — artificially low result; misses the standing-water exposure.
• Wrong bottle or improper preservation — invalid result.
• Single test — lead leaching is intermittent; multiple tests over months give a better picture.
• Hot-water tap test — not standard protocol; cold-water-only for testing.

Common variants

• DIY home kit (rough screening) vs. lab test (quantitative).
• First-draw (worst case, after stagnation) vs. flushed (baseline).
• Lead from solder (interior solder joints; pre-1986) vs. lead from service line (utility-side; pre-1940 WA hot zones).
• Lead testing vs. copper testing — companion test, often same lab panel.

Washington note

WA-specific lead-testing context:

WA DOH Lead Service Line Inventory (LSLI) — community water systems are required to inventory and notify customers about lead, galvanized requiring replacement, and unknown service lines under the federal Lead and Copper Rule Revisions (LCRR). The inventory deadline was October 16, 2024; as of early 2026, WA DOH reports the majority of WA Group A water-system service lines have been inventoried.

Pre-1940 Tacoma Hilltop and similar pre-WWII WA neighborhoods — historical lead service lines are documented in some WA cities. Check WA DOH LSLI records or contact your utility for the service-line material on your specific address.

Pre-1986 Seattle Cedar/Tolt-fed homes — soft acidic water plus lead solder is the high-risk combination for first-draw lead. Post-2003 SPU corrosion-control treatment raised distribution-system pH to about 8.0, reducing leaching, but pre-2003 the risk was higher and some interior lead may still leach in older homes.

WA-certified labs that handle drinking-water lead samples: Edge Analytical, Eurofins, Friedman & Bruya, others. Check current 2026 lab options before sending samples.

Free or subsidized testing — SPU and some other WA utilities have offered free at-home test kits or first-draw lead tests. Verify current 2026 program status before relying on a free option.

A few common scenarios:

New parent in pre-1986 Seattle bungalow — first-draw test at all faucets, especially kitchen and any drinking-water tap. POU RO if any test exceeds 5 ppb.

Pre-1940 Tacoma Hilltop home — verify with Tacoma Water about lead service line status. If lead service is documented, request replacement information.

Pre-purchase with old plumbing — lab lead test as contingency. Cost is small compared to negotiating leverage.

Vacation home returning to high-stagnation lead — run water 30 seconds before consumption.

FAQ

What’s the EPA action level for lead in drinking water?

Currently 15 parts per billion (ppb). Under the Lead and Copper Rule Improvements (LCRI), this lowers to 10 ppb effective late 2027. There is no “safe” level of lead — these are regulatory action thresholds, not health-protective levels. For households with children or pregnancy, target under 5 ppb.

Can I test my own water at home?

Yes. Home test kits cost $20–$50 at hardware stores and give semi-quantitative results. For precise numbers and regulatory comparison, send samples to a WA-certified lab — typically $20–$100 per sample. Many WA utilities also offer subsidized or free testing.

How often should I test?

For high-risk homes (pre-1986, with children, or after plumbing work), test annually. For lower-risk homes, every few years is reasonable. Re-test any time you notice color or taste changes in the water.