Full installation and approval timeline

Most DC, MD, and VA solar installs take 6 to 12 weeks from signed contract to your first kilowatt-hour. Some run faster, some slower, and the variability is mostly out of any installer's control. Here is what is actually happening during each phase.

Phase 1: site survey and design (1 to 2 weeks)

After you sign, an engineer comes out to take measurements, photograph the roof, and verify the electrical service can handle solar. Most assessments take one to two hours on site.

The design team then produces:

• A panel layout (where each panel goes on the roof)
• An electrical one-line diagram (how it connects to your service)
• A structural calculation (proves the roof can hold the array)
• A production estimate (how much it will generate annually)

You will see the design before it is submitted for permits. Speak up here if anything looks wrong.

Phase 2: permitting (2 to 6 weeks)

This is where most of the variability lives. Each jurisdiction is different.

• DC: DCRA permits typically come back in 2 to 3 weeks. Historic district properties take longer because they need HPRB (Historic Preservation Review Board) sign-off, which adds 4 to 8 weeks.
• Montgomery County, MD: 3 to 5 weeks
• PG County, MD: 4 to 8 weeks
• Arlington, VA: 2 to 4 weeks
• Fairfax, VA: 3 to 5 weeks

There is nothing an installer can do to speed up a permit office once an application is in queue. What we can do: submit a clean application that does not get kicked back for revisions, which is usually where weeks of delay come from.

Phase 3: installation (1 to 3 days)

The actual install is the fastest part. A crew of three to five installers can put up an 8 kW residential system in:

• One day for a straightforward pitched roof
• Two days for flat roofs with ballasted racking
• Three days for systems with battery storage or complex electrical work

You do not need to be home, but you will be without power for two to four hours when the inverter ties in.

Phase 4: inspection (1 to 2 weeks)

After install, the local jurisdiction sends an inspector to verify the work matches the permit. In DC, that is a DCRA inspector. In MD and VA counties, it is the local building department.

Most pass on the first try. When they do not, common issues are:

• Conduit routing that does not match the permit drawings
• A label that is missing on the disconnect
• A grounding lug that needs to be re-torqued

These are usually fixed within a day, but you will be re-inspected before the system can produce.

Phase 5: utility approval / Permission to Operate (2 to 6 weeks)

Even after the inspector signs off, you cannot turn the system on until the utility says so. This is "PTO" (Permission to Operate). The utility:

• Verifies the meter is bidirectional, or installs one if not
• Approves the interconnection
• Issues a PTO letter

Pepco's PTO timeline runs 2 to 4 weeks in normal periods, longer (4 to 6 weeks) in late summer when volume is highest. BGE and Dominion are roughly similar.

Phase 6: turn-on

Once PTO arrives, we can flip the system on. Production starts that day. SRECs start accruing. You will get a welcome email with your monitoring app login.

Why the range is 6 to 12 weeks

Best case: clean permit, fast inspector, utility on a slow day, six weeks total.

Worst case: HPRB review, kicked-back permit, busy utility, 12-plus weeks.

What you can do to keep it on the fast end: respond quickly when we ask for HOA approval, signed change orders, or roof-access logistics. Days of homeowner delay add weeks to total project time because they push you to the back of the queue at the next phase.