Use this guide
Choose the questions relevant to your situation. Expand each answer, save the checklist and request written clarification where evidence is missing.
Questions homeowners ask
Does this apply to every Seattle-area solar home?
Verify the electric provider on your service account and the permitting authority for the parcel. This guide addresses Seattle City Light interconnection; Seattle electrical permitting applies where the City is the authority. A mailing address or contractor’s service area does not establish either.
What belongs in the City Light application?
City Light lists electrical diagrams, inverter and module specifications, and a site plan. Extra service work needs a separate application. Ask the applicant to identify each submitted scope and reference.
Source: Seattle City Light: installing or upgrading a solar array. Reviewed 2026-10-06.
What must arrive before installation begins?
City Light sends a Permission to Construct letter after receiving the signed interconnection agreement. Its instructions say to wait for that letter before installation. Keep the actual letter and conditions.
Source: Seattle City Light: installing or upgrading a solar array. Reviewed 2026-10-06.
Is Permission to Construct the same as Permission to Operate?
No. City Light issues Permission to Operate after inspections pass and required payments are received. The completed installation cannot be permanently energized before PTO. Ask the installer for the final letter.
Source: Seattle City Light: installing or upgrading a solar array. Reviewed 2026-10-06.
Can every City Light customer receive export credits?
City Light prohibits export and net metering in its network areas, including most of Downtown and parts of First Hill, South Lake Union and University District. Confirm the actual connection location.
Source: Seattle City Light: installing or upgrading a solar array. Reviewed 2026-10-06.
Who provides the commissioning and inspection records?
City Light provides a Commissioning and Testing Attestation form. After the jurisdiction’s inspection passes, submit its proof and the signed form to the utility. Keep utility inspection completion separate.
Source: Seattle City Light: installing or upgrading a solar array. Reviewed 2026-10-06.
What changes when I expand an existing array?
City Light requires a new or modified interconnection agreement and electrical one-line diagram for expanded systems. Ask the applicant to document the revised configuration and required reviews before treating earlier records as sufficient.
Source: Seattle City Light: installing or upgrading a solar array. Reviewed 2026-10-06.
What electrical permit questions remain with the City?
Seattle requires electrical permits for wiring installation or alteration and directs applicants to determine plan-review requirements. Ask the qualified applicant which route covers your complete solar, battery and service scope. Keep the permit and inspection records; a utility letter does not answer every City requirement.
Source: Seattle: electrical permits and inspections. Reviewed 2026-10-06.
Why does solar production differ from billed electricity?
City Light’s solar bill separates grid energy imported and solar energy exported. Its usage comparison chart excludes solar generated and consumed on-site. Some customers have a production meter; its reading is not used to calculate the bill. Compare matching periods and measurement types.
Source: Seattle City Light: reading a solar net metering bill. Reviewed 2026-10-06.
What do the net meter balance and base charge mean?
City Light shows beginning credits, credits added or used, and the ending kWh balance. It also explains a daily base service charge multiplied by billing-period days. A credit balance is not a promise of a zero bill or cash payout.
Source: Seattle City Light: reading a solar net metering bill. Reviewed 2026-10-06.
Can a separate assessment replace these approvals?
No. Define which observation or assumption needs review, such as accessible roof conditions, shade inputs or a scope mismatch. Ask about qualifications, compensation, referral conflicts and exclusions. Solar Survey AI’s evidence methodology explains documentation; confirm homeowner service availability. A paid third-party report does not itself establish independence, issue a City permit or authorize utility operation.
Your decision checklist
- Verify the utility account and local permitting authority.
- Record submitted diagrams, equipment and separate service-work scope.
- Obtain the actual Permission to Construct before scheduling installation.
- Confirm network-area export restrictions for the real connection.
- Retain the commissioning attestation and jurisdiction inspection proof.
- Track utility inspection, charges and the final PTO letter.
- Keep revised approval records when expanding the system.
- Compare bill imports, exports and credit balances using matching periods.
Save or print this guide from your browser. Keep completed records privately.
Continue your research
Track the letters and the evidence behind them
| Checkpoint | Record | Question to resolve |
|---|---|---|
| Connection and scope | Utility account, location review and equipment list | Is export supported for this connection? |
| Before construction | Completed agreement and Permission to Construct | What conditions govern the planned work? |
| Jurisdiction completion | Permit, passed inspection and actual corrections | Does the completed record match the installed scope? |
| Utility completion | Attestation, inspection and payment records | Which item prevents operating authorization? |
| Operation | Actual Permission to Operate and handover | Who received the letter and what configuration does it cover? |
| Billing review | Dated import, export and credit-balance records | Are comparisons using the same measurement and period? |
Example: the homeowner receives Permission to Construct, but a later text says the system is ready to turn on. Ask for the actual operating authorization before treating that text as the final milestone. Have the qualified installer handle any authorized testing; a homeowner should not improvise equipment energization.
Example: two homes use similar equipment, but one is on a network connection with export restrictions. Do not copy the other home’s export-credit assumptions. Ask the utility and designer to explain the configuration and financial scenario that apply to the actual connection.
Illustrative record comparison: an inverter reports 450 kWh for a month while a utility record shows 180 kWh exported. Those are different measurements. The two numbers alone do not establish that the remaining 270 kWh were lost, nor do they prove direct consumption without matching records. Ask for dates, units and the measurement boundary before drawing a performance conclusion.
If official materials disagree about a permit threshold or application step, preserve the versions and ask the responsible City or utility reviewer to confirm the current route in writing. Do not select the most favorable statement or treat a saved older guide as a project-specific decision.
Continue with approval responsibilities, bill measurements, handover records and assessment scope and conflicts. Explore our location directory and Solar Survey AI’s evidence methodology; confirm available survey services for your property. Connected homeowner monitoring and free remote diagnosis remain coming soon.
About these guides
Published by Solar Survey AI, a commercial survey-services company. Our original decision checklists are recommendations; linked authorities support the referenced facts. We may benefit if you purchase our services. This is not independent certification of our company, a project-specific engineering decision or personal tax/legal advice. Local rules, contracts and site evidence control individual decisions. Reviewed 2026-10-06.
For available survey or inspection services, confirm your project scope and availability with our team. Our planned free homeowner remote diagnosis remains coming soon.
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