CDPH Lead Inspector/Assessor California State Practice Exam

For properties built during 1960-1977, when is random sampling of units acceptable?

1. For any number of units

2. More than 5 similar units

3. More than 10 similar units

4. More than 15 similar units

The correct answer is: More than 10 similar units

Random sampling is a method used in lead assessments to determine the presence of lead-based paint in a representative group of units within a property. For properties built between 1960 and 1977, regulations allow for the use of random sampling primarily when evaluating multiple similar units, which helps to reduce the time and cost of inspection while still providing reliable data. The threshold of using random sampling in this context is set at more than 10 similar units. When a property has more than this number of similar units, it becomes feasible to generalize findings from the sampled units to the entire group. This captures a sufficient variety of conditions and possible lead exposure scenarios that may exist across the units, thus strengthening the validity of the assessment results. Using a smaller number of units for random sampling may not provide an adequate representation of the conditions throughout the property. Hence, while properties with fewer than 10 similar units would typically require detailed inspections of each unit, having more than 10 allows for sampling while still maintaining a reliable level of confidence in the assessment's findings.