What happens if you skip the permit (and you needed one)
- Stop-work order from San Dimas Building Department carries a $500–$1,000 fine, plus you must undo the install or hire a licensed electrician to pull a permit retroactively (adding $400–$600 in back fees and re-inspection costs).
- Insurance denial: most homeowner policies exclude unpermitted solar from coverage, leaving you liable for storm/fire damage ($20,000–$50,000 rooftop damage uninsured).
- Refinance or home sale blocker: title company will flag unpermitted solar in TDS disclosure, lender will demand removal or retroactive permitting (costing $1,500–$3,000 in expedited fees and contractor liability insurance).
- SCE (Southern California Edison) disconnection: utility can refuse net-metering credits and demand system removal if interconnection was never filed; you lose all incentive revenue ($1,200–$3,000 annually on a 5 kW system).
San Dimas solar permits — the key details
San Dimas Building Department requires TWO separate permits for every grid-tied solar installation: a Building Permit (structural, roof, mounting compliance) and an Electrical Permit (NEC Article 690 and 705 compliance, disconnects, labeling, conduit). California state law (AB 2188) mandates same-day or 5-day issuance for complete, compliant applications, but San Dimas interprets 'complete' strictly—missing a roof structural report or an SCE pre-approval letter will restart the clock. The city's building division conducts structural plan check before electrical; this means your roof engineer's stamp and roof load calculations (typically $300–$500 from a structural PE) must be submitted with the building permit application. All systems must comply with NEC Article 690 (Photovoltaic (PV) Systems), which requires rapid-shutdown capability (NEC 690.12) that de-energizes DC conductors on the roof within 10 seconds of grid loss or manual shutoff. This is non-negotiable in San Dimas and must be labeled on your one-line diagram with the specific hardware model (SolarEdge or Enphase microinverters, or a combiner-box shutoff relay). Many DIY or out-of-state installers fail to specify this, causing automatic plan-check rejection.
San Dimas sits in PSPS (California's Public Safety Power Shutoff) territory, and neighborhoods in the foothills (areas like Sycamore Canyon, Royal Oaks) are designated high-fire-hazard zones by Cal Fire. If your system includes battery storage over 20 kWh (e.g., 2x Tesla Powerwall = 27 kWh usable), San Dimas Fire Marshal requires a separate Energy Storage System (ESS) permit, fire-separation distance verification (typically 10 feet minimum from combustible structures), and a fire-suppression plan. Battery systems also trigger Title 24 (California's energy code) review by the city's energy analyst, adding 1–2 weeks. If you're in a PSPS-high-risk zone and want grid-isolation capability (intentional islanding), you must notify SCE in writing on your interconnection application; this requires additional protective relaying and may delay SCE approval by 3–4 weeks. Non-battery, grid-tied-only systems in PSPS zones do NOT require extra fire review, but the city will note your PSA eligibility in the permit jacket.
Utility interconnection is a mandatory parallel track: you cannot finalize a San Dimas building or electrical permit without proof that SCE (or your local water authority, if you're in a municipal utility zone) has accepted your interconnection application or issued a preliminary approval. This is not a 'nice to have'—it is a city enforcement point. SCE's online portal (SCE.com) allows you to file Net Metering Agreements (NMA) for systems under 30 kW. Most homeowners find that SCE issues a preliminary approval within 10–15 days if the application is complete; the city will then issue your building permit. Full SCE permission to operate (PTO) comes after city electrical inspection, not before. Many applicants misunderstand this sequence and assume SCE must approve before city does; in practice, city issues permits contingent on SCE pre-approval, then both parties coordinate final inspections.
San Dimas has adopted the 2022 California Building Code (Title 24, Part 2), which incorporates IBC 1510 (Roof Coverings and Recovering) and requires that roof penetrations for mounting hardware be sealed per manufacturer specs and IRC R905. If your roof is within 5 years of its design life, some installers recommend reroofing first to avoid future water intrusion and liability disputes. The city does NOT require you to reroof, but inspectors will note any existing roof damage or improper flashing in the inspection report, and you assume responsibility. Flat roofs (common in San Dimas coastal areas) must use ballast-mount systems (racked or attached) with documented wind and uplift calculations for your specific roof load rating; the city requires wind-speed analysis per ASCE 7-22 for systems in high-wind zones (coastal San Dimas qualifies). Pitched roofs in foothills can use standard rafter-attached rail systems, but you still need roof structural sign-off if your system exceeds 4 lb/sq ft dead load.
Owner-builder rules in California (B&P Code § 7044) allow you to pull a building permit as the property owner, but NOT an electrical permit—electrical work on any solar system must be performed and signed off by a California-licensed electrician (C10 or B license). This means even if you buy and mount the panels yourself, the electrical rough-in (conduit, disconnects, inverter hookup to main panel) must be done by a licensed contractor. Many homeowners try to do electrical themselves and face permit denial and forced removal. The building permit itself typically costs $250–$400 in San Dimas (flat fee or 0.5% of valuation, whichever is higher); the electrical permit is usually $200–$300. Battery storage adds a $100–$200 ESS admin fee. Total permit cost for a 5 kW rooftop system is typically $400–$700; a system with 2x Powerwall can run $600–$900. Timelines: building permit 5–7 days if structural report is included; electrical permit 3–5 days; inspections (structural, electrical rough, electrical final, SCE witness) typically occur over 2–4 weeks, depending on inspector availability. You should plan 4–6 weeks from application to final sign-off and PTO.
Three San Dimas solar panel system scenarios
San Dimas structural and fire-hazard zones: why roof reports matter
San Dimas city planning divides neighborhoods by fire risk and seismic hazard. Foothills areas (Sycamore Crest, Royal Oaks, highest elevation zones) are designated State Responsibility Areas (SRA) or Very High Fire Hazard Severity Zones (VHFSZ) by Cal Fire. Coastal and lower-elevation neighborhoods (Avocado Heights, Covina border) are lower-risk. This matters for solar because Cal Fire requires that any rooftop load (solar, HVAC, etc.) not degrade your home's fire defensibility or create ember-trapping conditions. San Dimas Building Department enforces this by requiring a roof structural engineer report for ALL systems over 4 lb/sq ft, regardless of neighborhood. Most 5–7 kW residential systems fall in this range. The engineer's report must certify not only that your roof trusses can carry the load, but also that flashing and mounting hardware meet current IRC R905 (Roof Coverings and Recovering) standards, reducing water-intrusion risk and fire-spread pathways. If you live in a VHFSZ and your roof is due for replacement within the next 3–5 years, some insurers (State Farm, Allstate) will pressure you to reroof before solar installation; this is not a code requirement, but it is a practical insurance step. The city does not mandate reroofing, but fire inspectors may flag old composition shingles or missing shingles as risk factors in their final walkthrough.
NEC 690.12 rapid-shutdown and San Dimas plan-check rejection patterns
California adopted rapid-shutdown (NEC 690.12) as mandatory in 2014, and it remains a top cause of permit rejections in San Dimas because applicants either omit it from electrical diagrams or claim exemption incorrectly. NEC 690.12 requires that all DC conductors on or in your roof be de-energized to 80 volts or less within 10 seconds of grid loss or manual shutdown. This protects firefighters from electrocution. There are three compliant methods: (1) Enphase IQ7 microinverters (rapid-shutdown built-in, no extra hardware), (2) SolarEdge inverter + SolarEdge power optimizers (module-level shutdown), or (3) string-inverter system with a dc-side manual disconnect plus a Fronius Symo or Victron rapid-shutdown relay. San Dimas electrical inspectors verify rapid-shutdown compliance by looking at your one-line diagram for either microinverter notation or explicit shutoff hardware labeling with model number and voltage cutoff spec. If your diagram just says 'rapid-shutdown capable' without model/part number, the inspector will reject it and ask you to resubmit. If you propose a standard string-inverter setup (like Enphase older models or SMA sunny tripower without rapid-shutdown relay), the city will deny your electrical permit outright. This is not negotiable. Many DIY installers from out of state assume their inverter is 'good enough'; it rarely is in California.
245 E. Foothill Boulevard, San Dimas, CA 91773
Phone: (909) 394-6210 | https://www.sandimas.ca.gov/government/departments/community-development
Monday–Friday, 8:00 AM–5:00 PM (walk-in and phone); verify hours on city website
Common questions
Can I install solar myself in San Dimas without hiring a contractor?
You can pull a building permit as the property owner and mount the panels yourself (owner-builder under CA B&P Code § 7044), but you CANNOT pull an electrical permit or perform any electrical wiring yourself. The electrical portion—conduit, disconnects, inverter hookup, main-panel integration—MUST be done by a California-licensed electrician (C10 or B license). San Dimas Building Department will not issue an electrical permit or final sign-off if the electrician line on the application is unsigned. Many DIY installers discover this too late and are forced to hire a contractor to redo the work and re-pull permits, costing an extra $1,500–$3,000.
How long does it take to get a solar permit from San Dimas Building Department?
Building permit: 5–7 days if your structural engineer's report is complete and included with the application. Electrical permit: 3–5 days if the one-line diagram and rapid-shutdown hardware are specified correctly. However, San Dimas does not issue electrical permits until the building permit is approved, so the sequence is building first, then electrical (not parallel). Inspections (structural, electrical rough, electrical final, SCE witness) typically take 2–4 additional weeks depending on inspector availability. Total timeline: 3–4 weeks from complete application to final sign-off and Permission to Operate, assuming no rejections or rework. If your application is incomplete (missing structural report or rapid-shutdown hardware specs), add 1–2 weeks for resubmission and re-review.
Do I need a roof structural engineer report for my 5 kW solar system?
Yes, if your system weighs more than 4 lb/sq ft (dead load), which is typical for a 5 kW rooftop installation. San Dimas Building Department requires a stamped engineer report from a California PE certifying that your roof trusses and materials can carry the added weight and that flashing/penetrations meet IRC R905 standards. Cost is typically $350–$550. If your system is under 4 lb/sq ft (e.g., lightweight ballast mount on a flat roof, or a 2 kW microinverter system), you may be able to skip the engineer and use the equipment manufacturer's structural certification instead; ask the city during pre-application consultation.
What is rapid-shutdown and why does San Dimas require it?
Rapid-shutdown (NEC 690.12) is a safety feature that de-energizes all DC (direct current) wires on your roof within 10 seconds of grid loss or manual shutoff. This protects firefighters from electrocution when battling a roof fire. San Dimas Building Department enforces this as non-negotiable on every solar permit. To comply, you must either use Enphase IQ microinverters (rapid-shutdown built-in), SolarEdge inverter with power optimizers, or a string-inverter system with a Fronius/Victron rapid-shutdown relay. Your electrical diagram must list the specific hardware model number and voltage cutoff specification (e.g., 'SolarEdge DC Switch Module P/N SE-RSD-3-27, 80V shutoff'). If your one-line diagram omits this detail, the city will reject your electrical permit and require resubmission.
Do I need Southern California Edison (SCE) approval before San Dimas issues my permit?
No, but you must have SCE pre-approval or a submitted application on file before San Dimas will finalize your electrical permit. The typical sequence is: (1) submit building permit with structural report, (2) city approves building permit, (3) submit electrical permit with one-line diagram, (4) simultaneously file SCE Net Metering Application online (SCE.com), (5) SCE issues preliminary approval within 10–15 days, (6) San Dimas reviews electrical permit and may issue contingent on SCE pre-approval documentation (you provide SCE letter to city), (7) inspections occur, (8) city issues final sign-off, SCE issues final Permission to Operate. San Dimas will not sign off without proof that SCE has accepted your interconnection application.
What permits do I need if I add a battery backup system (Tesla Powerwall)?
Three permits total: (1) Building Permit (for mounting and structural), (2) Electrical Permit (for PV wiring + battery interconnection), and (3) Energy Storage System (ESS) Permit (if battery capacity exceeds 20 kWh). A 2x Powerwall system (27 kWh usable) requires ESS permitting, which includes fire-separation distance verification (10 feet from combustibles or a 2-hour fire wall), Title 24 energy code review, and Fire-Marshal sign-off. Add 1–2 weeks to your timeline and $150–$200 in ESS admin fees. If your garage is too close to the planned battery location and you need a variance, add 2–4 weeks and $300–$600 variance fee.
How much do solar permits cost in San Dimas?
Building permit: $250–$400 (flat fee or 0.5% of project valuation, whichever is higher). Electrical permit: $200–$300. Energy Storage System permit (if battery over 20 kWh): $100–$200 ESS admin fee. Total permit cost for a 5 kW rooftop system: $450–$700. Total for a system with 2x Powerwall: $600–$900. These are city permit fees only; they do NOT include engineering reports ($350–$550), contractor labor, or equipment. Check the city's current fee schedule on the Building Department website to confirm exact rates, as they are updated annually.
What happens if I don't get a permit for solar in San Dimas?
San Dimas Building Department enforces unpermitted solar through stop-work orders, utility non-interconnection, and enforcement fines. If a neighbor complains or an inspector discovers your system during a routine inspection, the city will issue a stop-work order (fine $500–$1,000) and require you to either remove the system or hire a licensed contractor to pull a retroactive permit (adding $400–$600 in back fees and reinspection costs). SCE will not issue net-metering credits or permission to operate unless your system is permitted and inspected by the city. Your homeowner's insurance will likely deny coverage for unpermitted solar, leaving you liable for damage. When you sell or refinance the home, title company will flag unpermitted solar in the title report, and the lender will demand removal or retroactive permitting before closing, often delaying or killing the deal.
Can San Dimas issue a solar permit same-day or next-day like other California cities?
California law (SB 379) allows expedited same-day or 5-day issuance for complete solar permit applications. San Dimas participates in this program for building permits ONLY if your structural engineer's report is included, your site plan is clear, and your mounting details are explicit. However, San Dimas does NOT issue electrical permits in parallel or same-day; the city requires that the building permit be approved first, then the electrical permit application proceeds (typically 3–5 days after building approval). This sequential workflow means you cannot expect true same-day approval for the complete solar project. Total time: 5–7 days for both permits if everything is complete and in order.
What if I live in a fire-hazard zone in San Dimas? Does that affect my solar permit?
Yes. If you live in a State Responsibility Area (SRA) or Very High Fire Hazard Severity Zone (VHFSZ)—common in Sycamore Crest, Royal Oaks, and higher-elevation San Dimas neighborhoods—Fire Marshal may conduct an additional review of your roof structural report and mounting flashing to ensure they do not create ember-trapping conditions or degrade fire defensibility. You do NOT need a separate fire permit for rooftop solar without battery storage, but the Fire Marshal may comment in the building permit record. If you add battery storage over 20 kWh, Fire Marshal WILL require ESS fire-separation distance compliance (10 feet clearance or 2-hour fire wall), which can delay permitting 2–4 weeks if your garage/structures are in the way.