City of Walnut

A city address is usually permitted by the city, not the county — but not always, and some authorities keep building and hand electrical to someone else. Getting this wrong costs the whole submittal, because every requirement below belongs to whoever actually holds jurisdiction. Check the overlays in the same pass: an HOA, a historic district, a windstorm certification or a system-size cap can reshape the design, and all of them are cheaper to find now than after the array is laid out.

• Is this authority the AHJ for residential solar at this address? Yes 95% · municipal code
• What does this authority permit itself, and what does it delegate? Both (in-house) 88% · municipal code
• Is a permit required for a residential rooftop PV system? Yes 95% · municipal code
• Is there a separate electrical permit, or is it combined? Separate 85% · fee schedule
• Is a HOA or architectural approval required first? No — and the City is barred from conditioning approval on one 95% · municipal code
• Is there a historic-district review? Only for City-designated historical landmarks/resources, via an ad-hoc committee — not a blanket district 65% · municipal code
• Is a Specific Use Permit or Council approval ever required? Yes, conditionally — a Use Permit may be required if the Building Official finds a 'specific, adverse impact' on public health/safety; appealable to the Planning Commission 90% · municipal code
• Is there a system-size cap on residential generation? 10 kW AC nameplate / 30 kW thermal, AND installed on a single- or duplex-family dwelling only (an eligibility gate for the expedited/ministerial path, not an absolute prohibition above it) 92% · municipal code

Several authorities require the electrical permit to be pulled by a licensed electrician, or require the contractor to be registered with them BEFORE applying. Registration is not same-day. This is second on the list rather than fourth because it is the step most likely to stop the job before the drawings matter.

• Who is allowed to pull the electrical permit? Either (licensed contractor or owner-builder) 70% · permit application form
• Must the contractor be registered with this authority before applying? Yes (city business license, not a separate Building-Division registration) 65% · municipal code
• Is a homeowner permitted to self-install and self-permit? Yes 75% · permit application form

Almost everywhere wants a site plan, a one-line or three-line electrical diagram, equipment cut sheets with listings, and a structural attachment detail. Build it against the published checklist rather than the last jurisdiction you worked in — the checklist is what the reviewer marks against.

• What documents make up a complete submittal? A completed City building-permit application (paper 'carbon form'), the electrical-permit application, and the applicable fee — filed by mail or in person; WMC §2.36.040.D also directs the Building & Safety Division to adopt 'a standard plan and checklist' substantially conforming to the state Solar Permitting Guidebook, but no separate published checklist/standard-plan PDF could be located on the City's site (only the two generic permit-application forms and the fee schedule are linked from the solar page). 55% · department page (Wayback capture)
• How many copies, and in what format? Paper submittal only 70% · department page (Wayback capture)

Most authorities now take the whole application through a portal, and several states cap or constrain what a residential solar permit may cost. Check whether plan check is billed separately before you quote the job.

• Which permit portal does this authority use? No dedicated online portal — paper application filed by mail or in person at Walnut City Hall 80% · municipal code
• Can the whole application be completed online? No 78% · municipal code
• What does a residential solar permit cost? Residential: Plan Check $162.00, Permit $249.00 (base $194.20 + $54.80), Electrical $70.65 (+$57.60 if a meter/panel upgrade is needed), plus S.M.I. (0.00013 x valuation) and Building Fund ($1/$25,000 valuation) fees 55% · fee schedule (dated; superseded basis)
• How is the fee calculated? Flat (base building + electrical fee) plus Valuation-based add-ons (S.M.I. and Building-Fund fee) — but the City's Ord. 25-07 (2025) re-based all building fees to '2x the county fee' and electrical fees to '1.5x the county fee,' so the operative calculation is now a County-fee multiplier, not the flat 2016 numbers themselves. 60% · municipal code + fee schedule
• Is there a separate plan-check fee? Yes 65% · fee schedule (dated)

Interconnection is a separate process from the permit and usually the longer pole. Where the utility does not depend on the permit being issued, running both at once is the single biggest saving available on a residential job.

• Which utility handles interconnection here? Southern California Edison Co. 92% · city department page

The NEC edition a jurisdiction enforces is often a cycle behind the newest one published, and local amendments sit on top of it. Rapid shutdown, conductor sizing and labelling all change between editions, so the edition in force is the first thing to establish, not the last.

• Which NEC edition is in force? 2023 NEC (inferred via the 2025 California Electrical Code) 70% · municipal code (adoption clause) + inference
• Which building code edition is in force? 2026 Edition of the LA County Building Code, based on the 2024 International Building Code (LA County Ordinance No. 25-5683, effective 1 Jan 2026) — i.e., the 2025 California Building Code cycle 90% · municipal code
• Which fire code edition is in force? 2023 Los Angeles County Fire Code (LACFC), based on the adopted sections of the 2022 California Fire Code plus unadopted 2021 International Fire Code sections (County Ordinance No. 23-0008) — lagging the 2025/2026 building-code cycle 90% · municipal code
• Are there local amendments to any of the above? Yes 95% · municipal code
• What is the installation judged against? The LA County Building Code, Electrical Code, and Fire Code as adopted by reference (WMC Chs. 2.04, 2.08, 3.16) plus the City's own local amendments in those same chapters, and — for the expedited small-residential path — WMC Ch. 2.36's own standards (UL/IEEE-listed equipment, CPUC safety/reliability rules, and conformance to CBC/CRC/CEC/CFC as adopted). 88% · municipal code

Ridge setbacks and roof access pathways are fire-service requirements and they constrain the array layout. They are the most common cause of a redesign after the fire department comments on a plan set.

Nothing recorded for City of Walnut on this step yet — 1 question checked and found unpublished. The guidance above is general.

Which rapid-shutdown rule applies follows directly from the NEC edition in force, and the initiation device has to be at a location the fire service can reach and identify. This is inspected, and it is labelled.

• Is rapid shutdown required, and to which NEC edition? Yes, required — via whichever NEC edition is incorporated by the current wholesale adoption (inferred 2023 NEC / Art. 690.12) 65% · municipal code + inference

The NEC sets a baseline for permanent markings at the service equipment and the disconnecting means. On top of that, an authority may specify its own wording, and the utility may specify more again. Where any of them writes its own text, a generic off-the-shelf label set will not pass — this is the detail most often fixed on a return visit.

• Which placards does this authority require at the service equipment? LACoFD's 'F.D. – ELECTRICAL / BLDG DISCONNECT / #X of Y' placard at the service/disconnect equipment (retained LACoFD scope, applies regardless of city delegation of conventional PV review) 85% · fire-agency guide
• Does the authority specify placard wording of its own? Yes 90% · fire-agency guide
• Does it specify letter height, colour or material? Exterior placard: min 2in x 3.5in, weather-resistant plastic, engraved, red letters on yellow background, Arial all-caps, min font size 24 (28 bold for 'F.D.' and '#X of Y'). Panel-interior placard: min 7/16in x 3/4in, same colors, Arial all-caps bold min size 24. Attached with permanent epoxy. 90% · fire-agency guide
• Is a site plan / facility map placard required, and what must it show? A site plan is required for ESS installations specifically (LACoFD guide, min scale 3/32in=1ft) documenting equipment/clearances; no distinct general 'facility map placard' for standard rooftop PV was found on the City's own materials. 55% · fire-agency guide
• Where must the labels be placed? At the electrical service equipment / building disconnect(s), exterior and panel-interior, per LACoFD's placard spec 75% · fire-agency guide

Where the AC disconnect must sit relative to the meter is usually the utility's rule, not the building department's. Battery storage frequently carries its own permit, its own inspection and its own fire conditions.

• Must equipment be on a specific approved list? Yes 85% · municipal code
• Are batteries permitted, and under what conditions? Permitted, but reviewed/inspected directly by LACoFD (not delegated to the City) with defined clearances: min 5 ft from lot lines/public ways/other buildings/combustibles/hazmat, min 10 ft from vegetation, min 3 ft from doors/windows/operable openings/HVAC inlets into habitable space 88% · fire-agency guide
• Is there a separate ESS permit or inspection? Yes — LACoFD performs its own separate ESS plan review/field inspection regardless of city building-permit delegation 85% · fire-agency guide + fee schedule
• Is a ground mount treated as a structure? By inference, yes — no PV-specific carve-out found 55% · municipal code (definitions) + inference

Booking is a portal, a phone call or an email depending on the authority, and the notice required is rarely zero. Book before the work is finished rather than after — the lead time, not the work, is usually what sets the date.

• How is an inspection booked? Phone (voicemail) 90% · department page

Some authorities inspect their own solar work; some delegate it, and a few do not inspect the PV equipment itself at all. Who is coming determines what they will look at.

• Does this AHJ perform its own final solar inspection? Yes (self-performs), with a possible fire referral 90% · municipal code
• If delegated, to whom? Los Angeles County Fire Department (Consolidated Fire Protection District) — only when the Building Official refers a job for fire inspection, or automatically for ESS/BIPV (LACoFD's own retained scope) 88% · department page + municipal code

A rough-in or mid-roof inspection, where one is required, has to happen before the work it covers is closed up. Missing a stage means opening something back up, and it is the most expensive kind of correction.

• Which inspections are required, and in what order? A single consolidated building-division inspection for expedited-eligible small residential PV (no separate rough-in/final split), with a possible separate fire inspection if referred 85% · municipal code
• Is a rough-in or mid-roof inspection required? No 78% · municipal code

The approved plan set, the permit, and the equipment listings should be on site and reachable. Inspectors routinely verify that installed equipment matches what was approved, and that the labels are the ones the plan set promised.

• Is there a published inspection checklist? No 65% · department page (absence, Wayback-checked)

Passing gives you a final or an equivalent sign-off. That is not the same as permission to operate: PTO comes from the utility, and who tells the utility the inspection passed varies. A system left switched off for weeks is usually waiting on this handover.

• What is issued on pass? Final (building-division sign-off) — no CO, green-tag, or letter terminology found specific to residential PV 50% · municipal code (inference)
• Who notifies the utility for PTO? Installer/applicant 88% · municipal code
• Is there a re-inspection fee? $97.10 (City, per the 2016 fee schedule, described as 'Excess Inspect / Expired') for standard building inspections; LACoFD separately charges $98.00 for 'additional inspections after initial inspection and one reinspection' on fire-referred/ESS jobs 60% · fee schedule (dated) + fire fee schedule
• How are corrections issued and cleared? A written correction notice detailing all deficiencies is sent to the applicant for resubmission (for incomplete applications); a failed field inspection authorizes a subsequent inspection 70% · municipal code