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WALDO (Wisconsin Asbestos and Lead Database Online) gives access to general information on a property's compliance with Wisconsin standards on lead-based paint. Another feature is its use as a directory for locating lead inspectors and related service providers by region. The history and purpose of WALDO are explained below.


The Department of Health Services developed WALDO in response to a law called 1999 Wisconsin Act 113. This Act revised Wis. Stat. ch 254, subch. II. Also, it encourages property owners to eliminate hazards from lead-based paint by bringing their properties into compliance with statewide standards.  It is intended to reduce the incidence of childhood lead poisoning and improve the condition of housing stock in Wisconsin.

The older the property, the more likely that lead-based paint is present. Lead was put into paint because it increases durability and longevity. Homes built before 1950 pose the highest risk. Lead in paint was banned in 1978 because many children were being lead-poisoned. 

Lead-based paint is a potential health hazard, particularly for young children. In fact, deteriorated or damaged lead-based paint is the primary cause of childhood lead poisoning. Lead poisoning can cause growth, behavior, and learning problems in children. The effects of lead poisoning cannot be reversed and the damage may be permanent. 


Certified lead inspectors and risk assessors will register properties in WALDO following a successful investigation. The property owner is then issued a certificate at the lead-safe or lead-free level.

The lead-free certificate means an inspection was conducted, which includes collecting paint and dust wipe samples that were tested for lead. The samples are taken from different interior and exterior painted surfaces, including floors, doors, stairs, windows, and trim. If no lead-based paint was found, the property is registered in WALDO as lead-free.

The lead-safe certificate does not include collecting paint samples unless the property owner wants the paint tested. All paint is treated as lead-based paint unless proven to be lead-free.  The certified lead hazard investigator or risk assessor evaluates the property looking for potential lead-based paint hazards. The hazards include damaged paint, paint chips, dust, and situations that might cause paint to deteriorate. These situations include active water leaks, moisture damage, non-working downspouts and gutters, or windows, doors, and drawers that damage paint when opened or closed. If the property passes the investigation, a lead-safe certificate will be issued for a period of 9 months to 20 years.

You may want to use WALDO to find if a property is registered as lead-safe or lead-free if you meet one or more of the following criteria:

  • You are purchasing a home built before 1978.
  • You have young children and rent an apartment in an older building.  
  • Your child attends day care in an older home or building.

For more information, contact the Lead and Asbestos Section

Phone: 608-261-6876  |  Fax: 608-266-9711

Mailing address:
Division of Public Health
Bureau of Environmental and Occupational Health
Lead and Asbestos Certification Unit
P.O. Box 2659
Madison WI 53701-2659

Last revised September 27, 2022