Residential ADU and addition permits in Montgomery County, MD
102 residential ADU and addition permits were issued in Montgomery County, MD in the 8 weeks to Oct 16, 2026. Get them weekly by ZIP from Curbside Signal.
Source: Montgomery County MD (residential), Montgomery County MD (electrical), Montgomery County MD (mechanical). Oct 16, 2026 is the latest issue date the source has published.
Quick answer. In the 8 weeks ending Oct 16, 2026, 102 residential ADU and addition permits were issued in Montgomery County, MD, according to public records from Montgomery County MD (residential), Montgomery County MD (electrical), Montgomery County MD (mechanical). The busiest ZIP codes were 20912 (9 residential permits), 20904 (8 residential permits), 20815 (7 residential permits). The median declared value was $73,500 across 80 residential permits that list one. The latest permit date published is Oct 16, 2026.
Guarantee on every package: If a month comes in under half the 8-week average permit count for your ZIPs and trades, the next month is free. If a weekly file is ever late or missing, that month is free.
Every package includes your first file within 24 hours of purchase. If we can't deliver your first file within 24 hours of purchase, we refund you in full.
What an ADU and addition permit means in Montgomery County
A residential ADU or addition permit is a new unit or more square footage on an existing home. For an ADU builder or addition contractor it shows where lots are being built out, and the subs those jobs need.
In Montgomery County, permits were issued on 36 different days in the window; the most recent were Oct 15, 2026, Oct 14, 2026, Oct 13, 2026. The busiest ZIPs were 20912 (9), 20904 (8), 20815 (7).
By residential ADU and addition permit count, Montgomery County ranks #7 of the 51 ADU and addition pages on this site and #1 of 5 in MD.
- Mail the neighbors of each ADU.
- Pitch trades to the builders pulling the most permits.
- Track declared values by ZIP.
Other work on the same permits
Share of these 102 residential permits whose type or description also matches another trade. These are the follow-on and partner trades on Montgomery County jobs.
- Electrical: 19 residential permits (19%)
- Garage: 9 residential permits (9%)
- HVAC: 9 residential permits (9%)
- Plumbing: 4 residential permits (4%)
Weekly trend
Permits per 7-day period, ending Oct 16, 2026. n/c = not collected yet (before our pipeline started pulling this source). It is not zero. Striped bars are partly collected weeks.
Top permit types
| Permit type / subtype | Permits | Share |
|---|---|---|
| BUILDING RESIDENTIAL PERMIT / ADD SINGLE FAMILY DWELLING | 46 | 45% |
| BUILDING RESIDENTIAL PERMIT / ALTER SINGLE FAMILY DWELLING | 24 | 24% |
| ELECTRICAL PERMIT / INSTALL SINGLE FAMILY DWELLING | 15 | 15% |
| MECHANICAL PERMIT / INSTALL SINGLE FAMILY DWELLING | 6 | 6% |
| BUILDING RESIDENTIAL PERMIT / RESTORE AND / OR REPAIR SINGLE FAMILY DWELLING | 3 | 3% |
Busiest ZIP codes
| ZIP | Permits | Share | 8-wk avg / week |
|---|---|---|---|
| 20912 | 9 | 9% | 1.12 |
| 20904 | 8 | 8% | 1.00 |
| 20815 | 7 | 7% | 0.88 |
| 20895 | 7 | 7% | 1.12 |
| 20854 | 7 | 7% | 0.88 |
8-wk avg / week is the trailing 8-week weekly average we quote in coverage checks for that ZIP and trade. It counts every source in the ZIP and includes permits with unknown use, so it can be higher than this page's residential count.
Type stated in the permit
| Type | Permits | Share |
|---|---|---|
| Room addition | 43 | 42% |
| ADU | 28 | 27% |
| Second story | 1 | 1% |
Parsed from the permit's own type and work text. A permit can state more than one; many state none.
Sample rows
Anonymized: street address, permit number and any names removed. Subscribers get the full row with address, permit number and source link.
| Issued | ZIP | Permit type | Scope | Type | Declared value |
|---|---|---|---|---|---|
| 2026-10-15 | 20879 | BUILDING RESIDENTIAL PERMIT / ADD SINGLE FAMILY DWELLING | Addition/ADU | Room addition | $119,865 |
| 2026-10-06 | 20904 | BUILDING RESIDENTIAL PERMIT / ALTER SINGLE FAMILY DWELLING | Addition/ADU | ADU | $1,000 |
| 2026-09-23 | 20854 | ELECTRICAL PERMIT / INSTALL SINGLE FAMILY DWELLING | Electrical + addition/ADU | ADU | N/A |
| 2026-09-14 | 20905 | BUILDING RESIDENTIAL PERMIT / ALTER SINGLE FAMILY DWELLING | Addition/ADU | ADU | $23,000 |
| 2026-09-04 | 20879 | BUILDING RESIDENTIAL PERMIT / ADD SINGLE FAMILY DWELLING | Addition/ADU | Not stated | $207,305 |
| 2026-08-31 | 20841 | BUILDING RESIDENTIAL PERMIT / ALTER SINGLE FAMILY DWELLING | Addition/ADU | ADU | $10,000 |
Source
- Montgomery County MD (electrical): Permit records on data.montgomerycountymd.gov (dataset qxie-8qnp), published by Montgomery County MD (electrical). Source dataset. Collected window(s): Aug 21, 2026 – Oct 15, 2026. Last pulled Oct 18, 2026.
- Montgomery County MD (mechanical): Permit records on data.montgomerycountymd.gov (dataset ih88-a6aa), published by Montgomery County MD (mechanical). Source dataset. Collected window(s): Aug 22, 2026 – Oct 16, 2026. Last pulled Oct 18, 2026.
- Montgomery County MD (residential): Permit records on data.montgomerycountymd.gov (dataset m88u-pqki), published by Montgomery County MD (residential). Source dataset. Collected window(s): Aug 21, 2026 – Oct 15, 2026. Last pulled Oct 18, 2026.
Metric: Residential = the source marks the permit's use as residential (permits with commercial or unknown use are not counted). ADUs & Additions = the permit's type or work description matches the Curbside Signal ADU and addition rules. Counts exclude void or cancelled permits. Dates are the jurisdiction's permit issue date. Records are deduplicated on source and permit number. How we count. Part of the Washington-Arlington-Alexandria, DC-VA-MD-WV metro: every trade × city page there.
The honest limit. A permit usually means the job is already sold. We say that up front. The value is what happens around it:
- Neighbor marketing around active jobs: same-age houses on the same street.
- Cross-trade follow-on demand: new roof → solar, gutters, insulation; remodel → HVAC, electrical, landscaping, pool; new build → pest, security, landscaping.
- Competitor intelligence: which contractors pull permits where (where the jurisdiction publishes it), and who to recruit as subs.
- Early-stage projects for commercial trades and GC subs.
Follow-on: ADUs and additions drive HVAC, electrical, plumbing, solar and landscaping work.
Other trades in Montgomery County, MD
Residential permits in the same window, by trade.
Questions
How many residential ADU and addition permits were issued in Montgomery County, MD recently?
102 residential ADU and addition permits in the public records we pulled, the 8 weeks ending Oct 16, 2026. Source: Montgomery County MD (residential), Montgomery County MD (electrical), Montgomery County MD (mechanical).
Which Montgomery County ZIP codes have the most ADU and addition permits?
20912 (9 residential permits), 20904 (8 residential permits), 20815 (7 residential permits), by residential ADU and addition permit count the 8 weeks ending Oct 16, 2026. 29 ZIP codes had at least one permit.
What is the median declared value of a residential ADU and addition permit in Montgomery County?
$73,500, across 80 residential permits that list a valuation. Declared values are what the applicant stated on the permit, not the contract price.
How do I get the Montgomery County ADU and addition permit list, and what does it cost?
Request a free 10-permit sample for your ZIPs first. ZIP Pack is $29/mo for one trade and up to 5 ZIPs every Monday; Metro Feed is $99/mo for a whole metro and up to 3 trades, delivered every Monday. Every package includes your first file within 24 hours of purchase. Guarantee on every package: If a month comes in under half the 8-week average permit count for your ZIPs and trades, the next month is free. If a weekly file is ever late or missing, that month is free.
Montgomery County ADU and addition leads, every Monday
Send your trade and ZIP codes. We'll reply with a real sample from the public records we pull, or tell you plainly that we don't cover you yet.