Mold remediation cost

The number that actually drives your quote is affected square footage, not house size. At the commonly cited $10-$25 per square foot, 50 square feet of moldy drywall runs about $500-$1,250 and 200 square feet runs about $2,000-$5,000. Get the square footage written on the estimate. Without it, three bids are three unrelated numbers.

Location inside the house matters because access does. This Old House's 2026 figures put attic work around $1,000-$4,000, basements $500-$3,000, crawl spaces $500-$2,000, a bathroom $500-$1,000, and HVAC system contamination $3,000-$10,000. HVAC is expensive because ductwork is hard to clean and easy to recontaminate.

Separately, a mold inspection is its own line item. Angi's 2026 data puts a mold inspection around $671 on average, commonly $303 to $1,045, driven mostly by home size and sample count. Remember the EPA's position before you buy one: if you can already see the mold, sampling usually tells you nothing you need.

Two tactics inflate mold bills. The first is testing you did not need, sold by the same company that then quotes the removal. The second is scope creep - containment, air scrubbers, and equipment day-rates billed across rooms that were never affected. Ask for a line-item estimate and ask what happens to the price if the affected area turns out smaller once the wall is opened.