The short version
Most residential mold remediation in Montgomery County falls somewhere between $1,500 and $6,000. Small, contained jobs on hard surfaces can come in under $1,000. Whole-home or multi-system projects commonly run $10,000 to $30,000. The spread is wide because the price is driven far less by the amount of mold than by what has to be removed, how hard it is to reach, and how long the structure takes to dry.
Typical Rockville ranges by job type
- Inspection with moisture mapping: a few hundred dollars, frequently credited toward the work. Lab samples are priced individually on top.
- Small contained area, hard surfaces: $500 to $1,500. One wall section of block, a utility closet, a section of tile.
- Basement wall or section, finished space: $1,500 to $4,000. Demolition of drywall and insulation, containment, cleaning, drying, and disposal.
- Full basement remediation: $4,000 to $10,000 depending on square footage and how much finish work comes out.
- Crawl space cleanup: $2,000 to $6,000, driven heavily by access and how much framing needs abrasive cleaning.
- Crawl space encapsulation with dehumidifier: $5,000 to $15,000, more with drainage work.
- Attic remediation: $2,000 to $6,000, rising to $4,000 to $10,000 with ventilation correction, air sealing, and new insulation.
- Bathroom wall or floor cavity: $1,500 to $5,000 before plumbing repair and tile work.
- Emergency water extraction and structural drying: $2,000 to $8,000 for a typical basement event, depending on category of water and duration.
- Whole-home projects: $10,000 to $30,000 and up.
Use the cost estimator to put a number on your own situation, then treat it as a planning figure rather than a quote.
What actually drives the price
Material porosity. This is the biggest single factor. Cleaning growth off sealed block is cheap. Removing and replacing drywall, insulation, carpet, and pad is expensive, and structural involvement in framing or subfloor is the most expensive tier of all. That is why the estimator asks how deep it goes before it asks anything else.
Access. A 24-inch crawl space entry, a steep attic, or a finished room with built-ins can double the labor for the same square footage. Crews price access honestly because it genuinely costs them time.
Water category. Clean supply-line water, storm runoff, and sewage are three different jobs with three different disposal and protective-equipment requirements. Sewage-category work costs substantially more and salvages far less.
Drying duration. Equipment on site for six days costs more than equipment on site for two. In Maryland's summer humidity, drying takes longer than most homeowners expect, and a crew that packs up early has not finished.
The source correction. Regrading, downspout extensions, a window well drain, an interior perimeter drain to a sump, or a dehumidifier. This can range from $200 of gutter work to $15,000 of drainage system, and it is the line item most likely to be missing from a low bid.
The problem found
After remediation
Reading a quote properly
Compare scopes, not totals. A written scope should name the moisture source and its correction, the containment method, exactly which materials are removed and to what margin, the drying plan and target standard, whether post-remediation verification is included, and who is responsible for rebuild. Two quotes $3,000 apart usually differ because one includes the drainage fix and the rebuild and the other does not, which makes the cheaper number the more expensive project.
Where insurance fits
Maryland homeowners policies generally follow the same logic as elsewhere: coverage tends to follow a sudden, accidental water event rather than the mold itself. A burst supply line is commonly covered; long-term seepage, poor maintenance, and surface flooding generally are not. Many policies carry a mold sublimit, often in the $5,000 to $10,000 range, and sewer or drain backup is usually an optional endorsement rather than standard. Our Maryland mold laws and insurance guide goes through the distinctions and what to document.
Where you can reasonably save
Do the exterior work yourself where you are able: gutters, downspout extensions, clearing window wells, pulling mulch beds back down below the foundation line. Handle genuinely small surface growth on hard, non-porous surfaces under about ten square feet. Get quotes in the shoulder seasons rather than during the August rush or immediately after a regional storm event. And do not skip the moisture-source correction to save money, because that is the one omission that guarantees you pay for the whole thing twice.