Data through September 2026 · updated 19 Oct 2026
1,775 home addition permits were issued in Montgomery County, October 2024 through September 2026: about 888 a year and 3% of all permits. 869 home addition permits in the last 12 months (Oct 2025–Sep 2026), 4% fewer than the 906 in the 12 months before. The busiest month is April. The usual one took 186 days from issue to the county's final. 20817 has the most, 177.
Permits issued each month, October 2024 through September 2026.
| Month | Permits |
|---|---|
| Oct 2024 | 99 |
| Nov 2024 | 75 |
| Dec 2024 | 60 |
| Jan 2025 | 55 |
| Feb 2025 | 63 |
| Mar 2025 | 83 |
| Apr 2025 | 107 |
| May 2025 | 64 |
| Jun 2025 | 73 |
| Jul 2025 | 75 |
| Aug 2025 | 93 |
| Sep 2025 | 59 |
| Oct 2025 | 76 |
| Nov 2025 | 70 |
| Dec 2025 | 56 |
| Jan 2026 | 58 |
| Feb 2026 | 58 |
| Mar 2026 | 60 |
| Apr 2026 | 85 |
| May 2026 | 81 |
| Jun 2026 | 82 |
| Jul 2026 | 87 |
| Aug 2026 | 78 |
| Sep 2026 | 78 |
By calendar month, 100 = an average month (the thin line). April is the busiest (130), January the quietest (76). A busy month at the permit counter usually means a longer wait for a contractor.
| Month | Index |
|---|---|
| January | 76 |
| February | 82 |
| March | 97 |
| April | 130 |
| May | 98 |
| June | 105 |
| July | 110 |
| August | 116 |
| September | 93 |
| October | 118 |
| November | 98 |
| December | 78 |
Permits issued Oct 2024–Sep 2025, at least 12 months before the file ends. Usual days is the middle permit among the 734 with a final date.
| Measure | Value |
|---|---|
| Permits issued Oct 2024–Sep 2025 | 906 |
| Finished | 81.0% |
| Usual days, issue to final | 186 |
| Middle half, days | 103–307 |
The value written on the permit at application, from 1,773 permits with one. Not a quote and not the final bill.
| Measure | Value |
|---|---|
| Usual declared value | $78,750 |
| Middle half | $30,000–$200,000 |
Counted at the property's ZIP code. Share is the part of the county's 1,775 home addition permits.
How the county filed these permits. We group its types into kinds of work; this is the split.
| Permit type | Permits | Share |
|---|---|---|
| Single Family Dwelling: add | 1,769 | 100% |
| Townhouse: add | 6 | under 1% |
Electrical (22,023)HVAC (15,557)Solar (7,854)Remodels & repairs (2,673)Garages, sheds & shade structures (2,548)New homes (1,590)Pools & spas (258)ADUs & casitas (229)
Home addition permits for other places in Washington, DC. Each permit office keeps its own file, so the numbers are not added together.
Arlington, VAWashington, DCFairfax County, VARockville, MDPrince George's County, MDHoward County, MD
Source: dataMontgomery: Residential Permit, Commercial Permits, Mechanical Permits and Electrical Building Permits (Department of Permitting Services), read 19 Oct 2026. We count permits issued October 2024 through September 2026; denied and withdrawn permits are left out.
Building, electrical and mechanical permits issued by the Montgomery County Department of Permitting Services, which covers the county outside the cities that run their own building offices: Silver Spring, Bethesda, Potomac, Germantown, Clarksburg, Chevy Chase, Olney, Wheaton, Takoma Park and the rest. The cities of Rockville and Gaithersburg issue most of their own building permits, so permits inside those cities are largely missing; a Rockville or Gaithersburg mailing address in this file is usually just outside those cities. Plumbing and gas-service permits are issued by WSSC Water, not the county, and are not in the file.
Counts are permits, not jobs: one job can need several permits. Nobody paid to be on this page and nobody can. Sources and definitions →
Free to reuse with attribution (CC BY 4.0). Please credit Contractor Records and link to this page. Suggested citation:
Contractor Records, "Home addition permits in Montgomery County, MD", https://contractorrecords.com/montgomery-county-md/addition-permits, data through September 2026, from Montgomery County Department of Permitting Services building-permit records.Link to a table: By month · Season · Days to final · Declared value · By ZIP code · Permit types.
Download the tables (CSV): Additions permits by month · Additions permits by calendar month (index) · Additions permits: days to final · Additions permits: declared value · Additions permits by ZIP code · Additions permits by permit type.