What happens if you skip the permit (and you needed one)
- Stop-work order issued by City of Farmington carries a $500–$1,500 fine; utility disconnects your system and demands removal within 30 days or faces lien attachment to your property.
- Insurance claim denial: homeowners' policies explicitly exclude unpermitted electrical work; solar damage or fire linked to unpermitted install voids coverage entirely, cost to you $20,000–$100,000+.
- Refinance or home sale blocked: lender title search reveals unpermitted solar; refinance denied or delayed 6–12 months pending retroactive permit (if available) or removal; TDS disclosure required in New Mexico, cost to remove $8,000–$15,000.
- Utility double-billing: El Paso Electric or SJEC can demand back-billing for net metering credits improperly claimed (12–36 months retroactive), $2,000–$8,000 clawback plus interest.
Farmington solar permit requirements — the key details
Farmington's Building Department administers both building permits (for the mounting structure, roof penetrations, and structural load) and electrical permits (for wiring, inverters, disconnects, and NEC Article 690 compliance). These are two separate permits issued by the same office, but they require two separate applications and two separate inspections. The building permit covers IRC R324 (solar) and addresses roof structural adequacy under NEC 690.39 and IBC 1510 (roof-mounted photovoltaic systems). For homes built before 1980 in Farmington, roof structural evaluation is mandatory if your system exceeds 4 lb/sq ft; most residential arrays (6–10 kW) weigh 4–6 lb/sq ft, so a PE-stamped roof analysis is almost always required. The electrical permit covers NEC Article 690 (photovoltaic systems), NEC 705 (interconnected power production systems), and NEC 230 (service entrance modifications if applicable). Rapid-shutdown capability (NEC 690.12) is required; your inverter or combiner box must satisfy this via arc-flash label and relay disconnection within 10 seconds of utility loss. String inverters and microinverters both satisfy this, but you must document it on your electrical diagram and submit it with the permit application.
Before you file either permit, you MUST submit an interconnection application to your utility — El Paso Electric or San Juan Electric Cooperative, depending on your address. Farmington straddles both territories; check your bill to confirm which utility serves you. EPE's interconnection study takes 1–2 weeks for systems under 10 kW; SJEC's process is similar. You will receive an interconnection agreement outlining the net-metering terms, any required utility-owned equipment (like a special meter), and the utility's conditions for energization. Do NOT proceed with your permit application until you have a signed interconnection agreement from your utility in hand. The City of Farmington will ask for this on your electrical permit application. Failure to obtain this agreement before filing is the single most common reason permits are rejected or delayed. Once you have the utility agreement, you can file both the building and electrical permits together; they will be routed to separate reviewers but can often be approved in parallel.
Farmington's frost depth is 24–36 inches depending on elevation and exact location; if your ground-mounted array includes buried conduit or a concrete pad foundation, it must be set below the frost line per the 2021 IBC. For roof-mounted systems, this is not an issue. The City also requires all PV wiring to be in conduit (NEC 690.31) — no exposed wiring clipped to the roof or wall. This is enforceable during rough-electrical and final inspection. Conduit fill (NEC 300.17) is another common rejection point; many DIY installs under-size conduit when running two strings in parallel, and inspectors flag it. Plan for 3/4-inch PVC or EMT for a typical 8–10 kW residential system. If you're upgrading your main electrical panel (common if your service is only 100 amps), that upgrade requires its own permit and inspection under NEC 705.12 (interconnected source limits). This can add 1–2 weeks and $200–$400 to your timeline and cost.
Farmington's Building Department issues permits on a first-come, first-served basis with a typical 2–3 week review window for straightforward residential solar. However, if your roof is flat or your home is historic (Farmington has a small historic district overlay), plan for 3–4 weeks. The City accepts applications in person at City Hall (Main Street, downtown Farmington) or via their online portal (check Farmington's official website for the current link; the portal was recently upgraded). Over-the-counter approvals for simple systems under 5 kW with no roof structural concerns are rare but possible if your application is complete. The permit fee structure is: building permit $150–$400 (based on valuation, typically 1–2% of system cost), electrical permit $200–$500 (flat rate or percentage-based, varies by scope). Request a fee quote before submitting; the Building Department staff will give you an estimate based on your system size and complexity. Battery storage (ESS) adds a third review layer: any system over 20 kWh requires fire-marshal review for hazmat storage and spacing (NEC 705.15), adding 1–2 weeks and $100–$300 in fees.
After permits are issued and your system is installed, you'll face three inspections: (1) Mounting and structural (Building Department), confirms roof attachment, conduit routing, and equipment clearance; (2) Electrical rough (Electrical Inspector), checks disconnects, rapid-shutdown, wiring, conduit, grounding, and system diagram accuracy; (3) Final electrical (Electrical Inspector), confirms all labels, tie-offs, and interconnection hardware are in place. After all City inspections pass, the utility schedules a witness inspection and installs your net-metering meter. Until that happens, your system is not legally energized. The entire process — utility application to final energization — typically takes 5–8 weeks. Budget for this timeline when planning installation; many installers promise 2–3 weeks and miss it because they underestimate the utility study phase or skip the structural evaluation upfront. Work backward: if you want to be live by December, file by late October. Farmington's climate (low humidity, intense UV, rare but heavy snow events in winter) makes robust mounting and conduit integrity especially important; inspectors are attentive to water intrusion and proper drainage at roof penetrations.
Three Farmington solar panel system scenarios
Roof structural requirements in Farmington: why PE-stamped evaluations matter
Farmington's climate — elevation ~5,500 feet, rare but heavy snow events in winter (10–15 inches on the valley floor, up to 30+ inches in nearby mountains), low humidity, intense UV — makes roof structural integrity a top concern for solar installations. The 2021 IBC Chapter 15 (Roof Assemblies and Rooftop Structures) and NEC 690.39 both require that roof-mounted PV systems not exceed the roof's design load capacity. For most residential homes in Farmington built before 1990, the original design snow load was calculated at 15–25 pounds per square foot (psf), depending on building year and code edition in effect at the time. A typical 6–8 kW residential PV array adds 4–6 psf to the roof; older wood-frame homes often cannot safely absorb this additional load without structural reinforcement.
The City of Farmington enforces this via the building-permit structural review process. If your system is under 4 psf (roughly a 3 kW or smaller array), a PE-stamped evaluation is usually waived; above 4 psf, mandatory. Most installers estimate 4–6 psf for typical residential panels, so PE evaluation is the rule, not the exception. A PE-stamped structural evaluation of your roof costs $500–$800 and takes 1–2 weeks. The engineer will review your home's original construction documents (you may need to request these from your county assessor or the seller's closing file), calculate the combined design load (snow + wind + PV + live load), and either certify that the roof is adequate or recommend reinforcement (typically sister-ing floor joists, adding collar ties, or bracing roof trusses). If reinforcement is required, you'll need a licensed contractor to perform the work and a separate framing inspection by the Building Department before the PV mounting inspection. This can add $1,500–$3,000 to project cost and 2–4 weeks to timeline. Always budget for a PE evaluation and assume reinforcement is likely if your home is over 30 years old.
Farmington's rare but intense winter storms also make proper mounting hardware critical. Snow load on a south-facing array can cause uneven melting and re-freezing, creating shear stress on mounting feet. All PV mounts in Farmington must be rated for at least 25 psf snow load (IBC 1508.1), and lag bolts or lag screws must be corrosion-resistant (hot-dipped galvanized or stainless steel, never plain steel). Stainless is preferred because Farmington's soil is alkaline (volcanic) and corrosion can accelerate in high-pH environments. The City's electrical inspector will check mounting hardware during the structural-mounting inspection; rust staining or plain-steel fasteners are automatic rejections.
NEC 690 and rapid-shutdown: documentation and labeling in Farmington
NEC Article 690 (Photovoltaic (PV) Systems) is enforced in Farmington via the 2021 National Electrical Code, which the City has adopted. The most commonly missed requirement is NEC 690.12 (rapid-shutdown of PV system), which mandates that within 10 seconds of utility loss or manual disconnect, all DC voltage in the PV array must drop to 30 volts or below. This is a safety feature designed to protect firefighters and utility workers who might be working on the roof or power lines after an outage or during an emergency. Many installers mistakenly believe that the utility disconnect switch alone satisfies this requirement; it does not. The inverter or combiner box must include a rapid-shutdown relay or module that detects loss of AC grid voltage and signals the PV combiner to open, de-energizing the string wiring.
String inverters (the most common residential topology) often satisfy rapid-shutdown via firmware: the inverter detects grid loss and internal relays trip the DC input, dropping array voltage to zero within 10 seconds. However, you must document this in your electrical diagram and label the combiner box and inverter clearly with 'RAPID SHUTDOWN REQUIRED — NEC 690.12' and the manufacturer's shutdown sequence. Microinverters simplify this: each microinverter can be shut down independently by a rapid-shutdown module, and the system is inherently rapid-shutdown-compliant. Battery-based systems add complexity: your hybrid inverter must isolate from both the grid and the battery upon shutdown to satisfy NEC 705.15 (interconnected electric power production systems). The City's electrical inspector will check for these labels and the system one-line diagram during rough electrical inspection; missing labels or no documented shutdown procedure is an automatic rejection that delays your final inspection by 1–2 weeks.
To satisfy Farmington inspectors, include in your permit application: (1) A one-line diagram clearly showing the PV array, combiner box, inverter, rapid-shutdown module (if separate), utility disconnect switch, and battery bank (if applicable); (2) Manufacturer spec sheets for your inverter and combiner box highlighting the rapid-shutdown function and response time; (3) A written description (one paragraph) of your shutdown sequence: e.g., 'Upon utility loss detected by the 8 kW string inverter, internal relay trips within 3 seconds, opening the DC string inputs and de-energizing the array to <30 V. Manual AC disconnect switch allows utility technician to further isolate inverter from grid.' This narrative, paired with the diagram, almost always satisfies the inspector. If you're unsure, request a pre-submittal meeting with the Electrical Inspector (free, takes 15 minutes) and bring your draft diagram. Many inspectors will flag missing elements before you submit, saving you a rejection.
City Hall, 206 W. Main St, Farmington, NM 87401
Phone: (505) 599-1275 (Building & Planning Department main line; ask for Solar/Electrical Permits) | https://www.ci.farmington.nm.us/departments/community-development (check for online permit portal; Farmington's portal is being upgraded; call to confirm current submission method)
Monday–Friday, 8:00 AM – 5:00 PM (Mountain Time)
Common questions
Do I need a permit for a small DIY solar kit (1 kW) I'm installing myself?
Yes. Even a 1 kW grid-tied system requires both a building permit and an electrical permit in Farmington, plus a utility interconnection agreement with El Paso Electric or San Juan Electric Cooperative before installation. There is no size exemption for grid-tied systems, period. Owner-builder rights apply (you can pull permits for your own owner-occupied home), so you can file the permits yourself. However, you'll still need NEC Article 690 compliance: proper conduit, disconnect switch, rapid-shutdown labeling, and grounding. If you're uncomfortable with electrical code, hire a licensed electrician to design and oversee the install; they'll file the permits on your behalf.
What's the difference between El Paso Electric and San Juan Electric Cooperative, and which one serves my address?
Farmington straddles two utility territories: El Paso Electric (EPE) serves most of the city and surrounding areas; San Juan Electric Cooperative (SJEC) serves rural areas and portions of the northwest quadrant. Check your electric bill — it will clearly state which utility is your provider. EPE's interconnection process is typically faster (7–10 days for a study under 10 kW); SJEC's is slightly longer (2–3 weeks) due to smaller staff, but both are equally legitimate. If you're unsure, call your utility and confirm your account address. Your utility interconnection agreement must be in hand before or with your building permit application; the City will not issue an electrical permit without it.
Can I install solar panels myself, or do I need a licensed electrician?
Farmington allows owner-builders to pull their own permits for owner-occupied residential work, including solar. However, NEC Article 690 requires that PV system design and installation comply with electrical code — specifically rapid-shutdown (690.12), grounding (690.35), conduit sizing (690.31), and interconnection standards (705.12). Most inspectors will accept a detailed one-line diagram and proper labeling if you self-install, but you are liable if the system fails inspection or causes damage. Many homeowners hire a licensed electrician to design the system and supervise rough-in, even if they self-install the mounting structure. This hybrid approach is cost-effective and reduces rejection risk. Structural work (mounting, roof penetrations) can be DIY if you have experience; electrical should involve a licensed professional or at minimum a pre-submittal consultation with the City inspector.
How much will my permit and fees cost in Farmington?
Building permit: $150–$400 (typically 1–2% of system valuation; an 8 kW system at $2.50/watt = $20,000 valuation = ~$200–$400 permit). Electrical permit: $200–$500 (flat rate or percentage-based; ask the City for a fee quote before submitting). Structural evaluation (if required): $500–$800. Fire-marshal review for battery storage (if over 20 kWh): $0–$100. Total permit and professional fees: $800–$1,800 for a typical 6–8 kW system. Utility interconnection study: No charge from El Paso Electric or SJEC for residential grid-tied systems under 10 kW. Get a fee estimate from the City before submitting; the Building Department will quote you based on your specific system size and scope.
What happens if the Building Department rejects my permit application?
Rejections are typically for: (1) Missing structural evaluation, (2) Incomplete one-line diagram or missing rapid-shutdown documentation, (3) No utility interconnection agreement on file, (4) Roof penetration details missing (flashing type, conduit routing), or (5) Undersized conduit or improper grounding plan. The City will provide a written rejection letter citing the specific code section and required correction. You then revise your application, resubmit, and the City re-reviews (usually 3–5 business days). Most rejections are corrected and resubmitted within 1 week. Avoid rejection by: having a PE-stamped structural evaluation ready upfront, submitting a detailed diagram with all components labeled, obtaining your utility agreement before filing, and consulting the City's solar permit checklist (available on their website or by phone) before submitting.
Can I interconnect my system to the grid without waiting for the utility's approval?
No. Backfeeding a solar system to the grid without a signed interconnection agreement and a utility-installed net-metering meter is illegal in New Mexico and will result in utility disconnection, fines, and possible removal of your system. El Paso Electric and San Juan Electric Cooperative both prohibit this. Furthermore, Farmington's Building Department will not issue a final approval until the utility confirms the system is properly interconnected. Always obtain your utility agreement first, then file with the City. The utility process is 1–3 weeks; it's the gatekeeper.
Are there tax credits or rebates that affect my permit cost or timeline?
The federal Investment Tax Credit (ITC) is 30% of system cost (solar plus installation, minus permitting fees). This is a federal tax benefit, not a permit requirement, so it does not affect your permit process. New Mexico has no state solar tax credit. El Paso Electric and San Juan Electric Cooperative occasionally offer rebates for new PV systems (typically $500–$1,500), but these are utility incentives, not building-department functions. Keep your permit and inspection receipts for your tax return; they document the system cost. Permitting fees are not tax-deductible under current IRS rules, but they are part of your basis for the ITC. Check the Inflation Reduction Act (IRA) 2022 for any updates to federal credits.
How long do I need to wait for inspections after I apply for a permit?
After your permit is issued (1–2 weeks after filing a complete application), you can schedule your first inspection (mounting and structural). Inspectors typically respond within 2–3 business days of your request. Farmington's Building and Electrical Departments do not assign inspection dates automatically; you must call or use the online portal to request them. Rough electrical inspection is usually 2–3 days after mounting inspection. Final electrical inspection is 1–2 days after rough inspection. If any inspection fails, you must correct the deficiency and request a re-inspection (1–2 more days). The entire inspection sequence for a straightforward system is 1–2 weeks. Don't assume inspections are automatic; proactively schedule them through the City.
My house is in a historic district (Old Town Farmington). Does that change the permit process?
Yes. Farmington's historic-district overlay requires Design Review Board (DRB) approval for any exterior modifications, including PV installations visible from a public right-of-way. Roof-mounted systems in the historic district typically require a DRB variance or a 'non-visible' installation (e.g., ground-mounted on the rear of a deep lot). DRB review adds 2–4 weeks to your timeline and may require architectural drawings. Contact the City of Farmington Planning Department (same phone number as Building) to determine if your property is in the historic district and what DRB approval entails. Some homeowners in the historic district opt for ground-mounted systems on the rear property line to avoid DRB delays. Budget for this early in your planning.
If I'm financing my system with a PACE loan, does that affect my permit?
Not directly, but lenders often require proof that permits are approved before they disburse funds. Farmington's Building Department and PACE lenders (typically a third party) coordinate to ensure the system is permitted before installation. You may need to provide your lender with a copy of your building and electrical permits before they release funds. This can delay your installation start date by 1–2 weeks if you're waiting for disbursement. Discuss this with your PACE lender when you apply for financing; they'll tell you what documentation they need from the City.