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Lead Paint Part II: Testing for Lead

In order to determine lead levels, the home in question should be professionally tested by a licensed inspector. As there are many ways to be exposed to lead, there are varying methods with which to test.

Testing Paint for Lead

Just because an entire house is painted, doesn’t mean everything is painted with the same paint. As such, some places could be contaminated with lead while others can be clean. Each different surface should be tested; walls, window frames, doors, and more. Interior and exterior should all be considered separately.

Professionals typically use two methods to test for lead in paint:

  • X-ray fluorescence (XRF): Portable detectors x-ray a painted surface to measure the amount of lead in layers in paint. Keep in mind that painting over a lead paint does not eliminate the problem; lead will just contaminate the new paint at the surface layer. Most home owners prefer XRF testing because it disturbs little if any paint and the results are instantly read by the inspector. 

  • Laboratory testing: Paint samples are removed from each surface to be tested using this method. An area of about two square inches is removed and sent to a laboratory for analysis. There will be a bare spot left on each surface where the paint was removed.

Testing Household Dust for Lead

Similar to how paint is tested, household dust is analyzed by a laboratory. Household dust can contain particles of lead released from lead painted surfaces or tracked in from contaminated soil outside the home.

A wet wipe is used to wipe along different surfaces, such as bare floors, window sills, and so on. Each sample is collected with a different wipe on a measured surface area of each section and then sent off for analysis at a laboratory.

Testing Water for Lead

Household water can become contaminated with lead from old pipes containing lead or lead solder in plumbing.

Water samples can simply be taken directly from the faucet. Typically inspectors will collect two samples. One is taken from water that has been standing in the pipes overnight or for eight hours or longer. The second is taken after letting the water run for several minutes to flush the lines. The samples are then sent off for analysis at a laboratory.

Testing Soil for Lead

Lead may be in the soil surrounding a home near streets or highways. To test the soil for lead, samples are taken from where children may potentially play or where the dirt is most likely to be tracked into the home. Then the samples are sent off to a laboratory for analysis.

Utilizing DIY & Home Lead Tests

Home testing kits for lead often use a chemically treated swab that changes color when coming in contact with lead. The swabs most commonly contain rhodizonate and sulfide; rhodizonate will turn red or pink when in contact with lead while sulfide will become brown or black.

While kits are often inexpensive and widely available for purchase, they are often not recommended when determining lead levels or making decisions about a property. In 2007, the U.S. Consumer Product Safety Commission (CPSC) evaluated several home test kits on a variety of paints and different levels of lead. More than half the tests produced false negatives and two tests produced false positives. The kits could have been affected by other substances such as iron, tin, or dirt, causing the colors in the kit to change or hide, interfering with accurate results. Some of the tests also had varying times to produce results, ranging from a few minutes to a few hours. As such, professionals should be used when testing for lead. They are able to use more accurate technologies, such as x-ray fluorescence, which aren’t available to the public.

If lead is found, it will need to be removed if children under the age of six will be living in the home. Next time we’ll discuss how this can be done and what precautions should be made during the process.

Dwell360 is a residential real estate firm based in Newton, Massachusetts, servicing the cities and suburbs of Greater Boston. We are focused on our customers and seek to provide information about home hazards such as lead to ensure domestic safety. Search for homes in Massachusetts and then give us a call.

Home Safe Environmental. Fact Sheets about Lead. Retrieved from
Massachusetts Health and Human Services. What Does the Massachusetts Lead Law Require?. Retrieved from
Conger, Cristen. (April 13, 2009). Do home lead tests really work?. Retrieved from
United States Consumer Product Safety Commission. (October 22, 2007). CPSC Staff Study: Home Lead Test Kits Unreliable. Retrieved from
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