The household members represents the number of individual members in the household that were served (includes both the Case served directly and those members served indirectly). For example:
John Smith was served today. John lives with Jane, Tom, and Sarah. This would represent 1 Household Served with 4 household members (John + Jane + Tom + Sarah).
Tammy White is served today...Tammy lives with her sister Julie. This would represent 1 Household Served with 2 household members (Tammy + Julie).