How to Test Your Water for Lead (Tap, Well, Filtered, Fridge)

Testing for lead in drinking water requires careful sampling because lead levels are often highest after water has been sitting in the pipes. The goal is to collect water in a way that reveals the true exposure levels from the plumbing you use every day. Here is a clear, science-backed method for each common water source. A sensitive lead-in-water screening test can determine whether your plumbing is contributing detectable lead.

1. Testing Lead in Tap Water (Kitchen or Bathroom)

1. Do not run the water beforehand — lead is most detectable after stagnation.
2. Collect first-draw water from the tap after at least 6 hours of non-use.
3. Use a certified or highly sensitive screening tool.
4. Repeat with a flushed sample after running the tap 1–2 minutes to see whether the lead source is the fixture or upstream plumbing.

This two-sample method helps distinguish fixture-based leaching from service line or pipe-borne lead.

2. Testing Lead in Well Water

Lead in private wells rarely comes from the aquifer. It typically originates from:

• Lead solder in well plumbing
• Brass well components
• Submersible pump parts containing leaded alloys

Sample directly from the tap you typically drink from. If results differ significantly from the raw well head, the plumbing is likely the source.

3. Testing Lead in Filtered Water (Pitcher or Under-Sink Filter)

Filters can reduce lead—but only if they are certified for lead reduction and replaced on time. To test filter performance:

1. Test the unfiltered tap first.
2. Then test water after filtration.
3. Compare results to confirm whether the filter is working or overdue for replacement.

4. Testing Water From a Refrigerator Dispenser

Refrigerator lines can leach small amounts of lead if they contain older fittings or pre-2014 brass.

1. Test the water directly from the fridge dispenser after stagnation.
2. Then test the same water source directly from the tap.
   A difference indicates the fridge line or internal components are contributing lead.

Choosing a Test

Lab tests measure exact ppb values, while rapid screening kits can quickly confirm whether lead is present above actionable levels. Homes with children, pregnant individuals, or older plumbing should test at least annually. A sensitive lead-in-water screening test detects trace levels quickly, making routine screening simple

By A. Anagnos, Biomedical Engineering Specialist