Porous materials contain openings or voids that can hold or transmit substances. Their behavior varies with the material, finish and condition.
What this means at your property
Water can enter carpet backing, unfinished wood or other absorbent layers without remaining visible on top. A coated surface can also have vulnerable edges or joints. The complete assembly matters when deciding whether drying or cleaning can reach affected areas.
Does porous always mean the item must be discarded?
No. The source of contamination, extent of damage, access and material condition all matter. Ask the assessment to explain the reasoning for cleaning, drying or replacement rather than relying on the label alone.