Methodology and sources

Remediation Cost shows public figures only. Dollar amounts are the ranges printed in published consumer cost guides, copied as printed with the guide's own update date. Rules are quoted from the agency, regulator or statute. Every figure lives in a data file with its source and checked date; pages, charts and the home page check are generated from those files.

Sources

Method and arithmetic

• Published ranges are shown as printed. They are national survey figures from the publisher, not quotes for a specific home. Where a guide contradicts itself (for example a FAQ figure that differs from its main table), the main table is used and the conflict is listed below.
• Arithmetic on a published rate is labelled. Area × the guide's per-square-foot rate gives the "by area" figures in the check and on pages. The test suite confirms the method against the guides' own tables: every row of the fire table equals floor area × $4–$7, and the flooded-basement size table equals floor area × $3–$7.50 (the 500 sq ft row rounds $3,750 up).
• EPA size categories follow EPA's wording: small under 10 sq ft, medium 10–100 sq ft, large over 100 sq ft. epa.gov blocks automated reading, so the text was read from EPA's own archive snapshot; the live page is linked beside it.
• Licensing checks apply each statute's own comparison: "greater than" in Florida and New York, "less than 25 contiguous square feet" exempt in Texas, contract value over the dollar line in Louisiana. D.C. leaves the threshold to regulation, which was not verified, so the check reports only the business license there.
• Rankings and comparisons (rank of a city, midpoint of a range, spread, share of an average claim) are computed from the same files at build time.

Left out, and why

• Sewage backup cleanup cost guide: Angi's sewage cleanup article could not be fetched on 2026-10-20; sewage is shown through the black-water (Category 3) rates of the water and basement guides instead.
• Town-level cost pages (NH/MA) and a county labor index: No published remediation price exists per town; scaling a national figure by a wage index would be an estimate, so those pages were not built.
• Mold remediation cost by mold type: The mold guide gives no figure by type.
• Angi FAQ figures that conflict with the article body (mold $1,125–$3,350; testing $450–$800; basement '$2,000 and $7,000 per square foot'): Internal conflicts or evident typos; the body tables are used.
• Maryland (licensing): Chapter 537 of 2008 created a mold remediation license under the Maryland Home Improvement Commission, but the 2016 Department of Legislative Services evaluation reports it was never implemented and recommended termination on July 1, 2019 if unfunded; current status not confirmed.
• Other states (licensing): Not reviewed in this release. A state-by-state survey from primary sources is pending; no state is described here as unlicensed.
• Per-state NFIP claim figures: fema.gov and the OpenFEMA API could not be read on the check date, so no state flood-claim figures are shown.
• EPA's material-by-material water damage table (Table 1 of the schools guide): its rows were not in the readable text, so it is not reproduced.
• Angi city pages: the city figures come from the city table in the national water damage guide. Angi's separate city pages are updated on their own schedule and can show different numbers (Seattle's page showed a different average when checked).

Gaps to fill next

A state-by-state survey of mold licensing from primary sources; mold remediation city figures if a publisher prints them; sewage cleanup ranges once the publisher's page can be read.

Data version 2026-10-20. Corrections: hello@remediationcost.com.