Key points
- 20,155 owner-hidden residential records
- 18,077 records with plausible known years
- Aggregate ZIP results only—no addresses or owners
- Structure year is not roof-installation history
Why publish this cross-check
The Census provides an estimated Waldorf housing-unit distribution, while Maryland's assessment data provide a separate administrative-record view by premise ZIP. Comparing the two can test whether a broad local age pattern appears in more than one source without exposing any property or owner.
Assessment-data method
The analysis selected only premise ZIP, published land-use class, and C.A.M.A. year built from Maryland's owner-hidden Charles County dataset. It retained records in ZIPs 20601, 20602, and 20603 whose land use is Residential (R), treated years 1700–2026 as known, and aggregated the results locally.
What was deliberately excluded
No street address, owner name, account number, parcel identifier, assessment value, property-level record, contact information, or inferred roof condition was retained or published. The downloadable file contains only the aggregate counts shown on this page.
Why the Census and assessment totals differ
The ACS estimates housing units for the Waldorf census geography and includes sampling uncertainty. Assessment records are administrative records filtered by premise ZIP and residential land-use classification. Their denominators and boundaries differ, so their totals must not be treated as interchangeable.
How to interpret the result
The assessment data show that the 1990–2009 share varies across the three ZIPs and that 20603 has the highest share among known-year records. This supports asking homeowners for actual roof-installation evidence; it does not support assuming that any roof is original, old, damaged, or due for replacement.
Published aggregate results
Assessment records by Waldorf ZIP
Maryland's June 2026 owner-hidden Charles County assessment dataset contains 20,155 records classified residential in ZIPs 20601–20603; 18,077 have a plausible year-built value.
| Mailing ZIP | Residential records | Known year built | Built 1990–2009 | Share of known-year records |
|---|---|---|---|---|
| 20601 | 8,653 | 7,761 | 2,494 | 32.1% |
| 20602 | 4,248 | 3,879 | 858 | 22.1% |
| 20603 | 7,254 | 6,437 | 3,214 | 49.9% |
| Combined | 20,155 | 18,077 | 6,566 | 36.3% |
Assessment finding: 6,566 of the 18,077 known-year residential records were built from 1990–2009, or 36.3%. This says nothing about whether a roof is original, replaced, damaged, or due for work.
Census housing-unit cross-check
The Census Bureau's 2024 ACS one-year estimate counts 31,655 Waldorf housing units. The decade estimates below describe structures—not roof installations—and carry sampling uncertainty.
| Structure built | Estimated units | Published margin of error | Share of estimated total |
|---|---|---|---|
| 2020 or later | 1,673 | ±743 | 5.3% |
| 2010–2019 | 5,120 | ±1,564 | 16.2% |
| 2000–2009 | 6,571 | ±1,424 | 20.8% |
| 1990–1999 | 5,307 | ±1,384 | 16.8% |
| 1980–1989 | 5,650 | ±1,161 | 17.8% |
| 1970–1979 | 4,391 | ±1,467 | 13.9% |
| 1969 or earlier | 2,943 | — | 9.3% |
The combined 1990–2009 ACS estimate is 11,878 units, about 37.5% of the estimated total. The similar percentage is a directional cross-check only because the Census and assessment datasets use different units and geographic boundaries.
Census source: 2024 American Community Survey one-year estimates, table B25034. Assessment source: Maryland SDAT/MDP Charles County Real Property Assessments, owner names hidden, accessed July 17, 2026. Assessment counts include only records classified Residential (R) with premise ZIP 20601, 20602, or 20603; known year means 1700–2026. Percentages are calculated and rounded to one decimal. Neither source reports roof-installation dates or condition.
Questions homeowners ask
Does this dataset show the age of Waldorf roofs?+
No. It reports a structure year-built field, not roof installation, replacement, maintenance, storm exposure, or condition.
Why not publish property-level records?+
The local question can be answered with aggregate counts. Publishing addresses or identifiers would add privacy risk without improving the conclusion.
Can I reuse the aggregate table?+
Yes, with attribution to WaldorfMD Roofing's analysis and the underlying Maryland SDAT/MDP source, while preserving the limitations and not converting structure age into roof age.
Is 20603 proven to need more roofing work?+
No. Its larger 1990–2009 share does not establish roof history, present condition, homeowner intent, or demand for services.