Categories:

Light to Moderate: Pet has made only one or two deposits on the carpet in the same place. Even if there are multiple deposits around the room so long as the carpet backing has not been saturated it is considered Light to Moderate.

Moderate to Heavy: Pet has made multiple deposits on the carpet.  Carpet backing and pad has been contaminated.  Sub-floor may or may not be contaminated.

Heavy to Extreme: Carpet has literally been used as a litter box. Carpet backing, pad, and sub-floor have been thoroughly contaminated.

Another area will will look at will be:

Wall to wall wool
Wool area rugsContamination in the center of the room.