Environmental Protection Agency (EPA) Lead Risk Assessor Practice Exam

What is the minimum number of dwellings to sample in a multi-family building with 23 units using a targeted/worst-case approach?

1. 5 units

2. 10 units

3. 15 units

4. 10 units or 20%

The correct answer is: 10 units or 20%

In a multi-family building, a targeted/worst-case approach is often employed to assess lead risk effectively. The guideline for sampling typically includes determining either a percentage of the total units or a set minimum number of units to ensure the sampling is representative of the overall lead risk present in the building. For a building with 23 units, the approach dictates taking a minimum of either a set number of units or a percentage of those units. Specifically, sampling 10 units or 20% of the total units applies here. Given that 20% of 23 units equals 4.6, which rounds up to 5, this means that the minimum requirement will still be about ensuring a substantial sample to capture the worst-case lead exposure risks. Consequently, the choice to sample 10 units (as the specified minimum) or to reach a rounded percentage maintains a robust evaluation process. This ensures that the assessment is neither too limited nor too broad, allowing for credible results that reflect the potential lead hazards present. Sampling fewer than this number may not fully reveal the conditions across the dwelling units, while adhering to this rule supports a comprehensive risk assessment in a diverse living environment such as a multi-family building.