Off-Grid Living in Mono County, California

I researched Mono County's rules for off-grid living by reviewing Planning Division materials, Building Division standards, the Living Light guide, and cross-referencing with California's statewide framework. Here's what I found - and what remains unclear - explained in practical terms for someone actually planning to go off-grid here.

Zoning and Land Use: Permitted, but Designation-Dependent

Mono County uses a tiered zoning system: Rural Residential (RR), Mixed Use (MU), and others, each with its own permitted uses and requirements. The county does not enforce a countywide minimum lot size. Instead, lot dimensions are determined by your specific zoning category and, critically, by whether your septic and water systems can pass Environmental Health approval.

What this means practically: If you own or plan to buy land in Mono County, your first step should be to verify its zoning designation through the Planning Division website or by calling directly. Rural Residential zones are most common for off-grid scenarios. Once you know your zone, confirm the permitted uses listed in the General Plan for that designation. Lot size requirements then cascade from your septic and well permit applications - Environmental Health will determine whether your parcel is large enough and has suitable soil for a compliant system. Do not assume that owning five acres automatically qualifies you; Environmental Health performs site-specific evaluations.

Dwellings and Temporary Structures: RVs Allowed Under Conditions, Tiny Homes Unconfirmed

Long-term RV occupancy is permitted in designated avalanche zones in Mono County, but with strict limits: no more than six months in any single year for a continuous five-year period, and only with a Director Review permit from the county.

Practical implication: If you are considering living in an RV on off-grid land, you must first confirm whether your parcel falls within a designated avalanche zone (the Planning Division or Building Division can tell you). If it does, you can legally reside there seasonally under the six-months-per-year rule, provided you obtain the Director Review permit in advance. If your parcel is not in an avalanche zone, the RV occupancy window may be more restricted or subject to different rules; contact Planning directly to clarify.

Tiny homes - prefabricated or site-built structures smaller than 400 square feet - are governed by California Building Code standards, but I found no county-specific tiny home ordinance or approval pathway in Mono County's published materials. This is a significant gap: if you are planning a tiny home, the county may classify it as an ADU (accessory dwelling unit), a primary dwelling, or something else entirely, depending on site conditions and design. You must contact the Building Division before purchasing equipment or hiring a designer. This conversation should happen early, before you invest in plans.

Building Permits and Off-Grid Power Systems: Pre-Approval Required

California Title 24 (the state Building Energy Efficiency Standards) applies statewide and is enforced locally by Mono County's Building Division. If you are installing an off-grid power system - solar arrays, battery banks, wind generators, or hybrid systems - you must submit designs to the Building Division *before* installation and receive written approval.

What this entails: Off-grid power systems in Mono County are not a "build first, notify later" scenario. You will need to: 1. Hire or consult an engineer or qualified solar/battery installer familiar with California code 2. Prepare system designs that address structural safety, electrical code compliance, and fire safety 3. Submit plans to Mono County Building Division for Director approval 4. Receive signed approval before purchasing or installing equipment

Title 24 adds energy-efficiency requirements, which means your system design must demonstrate that your home meets or exceeds the state's efficiency baseline. This is more stringent than simply installing panels; the entire building envelope (insulation, windows, HVAC) factors into the calculation.

Also, Mono County enforces California's defensible space rules: 30 feet of cleared vegetation around most structures, and 100 feet for parcels larger than one acre (per Cal Fire standards). If your property is in a high-fire zone - common in parts of Mono County - this requirement is non-negotiable and affects both your ability to build and your ongoing maintenance obligations.

Septic Systems: Environmental Health and Lahontan Regional Board Both Have Jurisdiction

If you need an individual onsite wastewater treatment system (OWTS) - a septic system - Mono County Environmental Health and the Lahontan Regional Water Quality Control Board jointly set minimum lot dimensions and site-suitability requirements. If you propose both a septic system and a private well, you must have 40,000 square feet (roughly one acre) of usable land, or comply with a larger standard if the Lahontan Region's Basin Plan or an approved Local Area Management Plan requires it.

Why this matters: Septic approval is not guaranteed, even on large parcels. Environmental Health conducts a percolation test (perc test) to determine whether your soil can absorb and filter wastewater at the required rate. Mono County's terrain - much of it high desert with rocky, clay-heavy, or permafrost-adjacent soils - can fail perc tests. If your perc test fails, you may need an engineered septic system (aerobic treatment unit or constructed wetland), which is more expensive and requires additional permits.

If you have 40,000 square feet and both a septic and a well are proposed, Environmental Health will check the well-to-septic setback: typically 100 feet minimum, though the Lahontan Basin Plan may require more. Do not assume your 40,000 square feet will accommodate both systems; get the perc test and site assessment done first.

Composting toilets are not approved as primary systems in Mono County. I found no county rule allowing them as standalone alternatives. You may be able to use a waterless toilet *in addition to* an approved septic system (for example, in an outbuilding), but confirm this with Environmental Health before planning around it.

Greywater Reuse: County Standards Unconfirmed

I could not locate county-specific greywater standards in Mono County's published materials. This is a significant gap.

What California allows statewide: California's Plumbing Code permits laundry-to-landscape greywater systems in single-family homes without a county permit, provided the system follows 13 specific guidelines (no detergent, no irrigation of food crops, drainage below ground, no ponding, etc.). All other greywater systems - kitchen sink drain, shower, toilet, or more complex reuse systems - require a county permit.

What you must do: Before designing a greywater system, contact Mono County Environmental Health or Planning Division and ask explicitly: "What greywater reuse systems does Mono County permit for off-grid residential use, and what is the permit process?" Get the answer in writing if possible, because the rules may have changed since my research was completed. If the county has not clarified its own standards, defer to California's statewide baseline: laundry-to-landscape is permissible without a permit if you follow the 13 guidelines; everything else requires a permit application.

Rainwater Harvesting: County Standards Unconfirmed

Mono County's county-specific rainwater harvesting standards were not located in my research.

What California allows statewide: The California Rainwater Capture Act of 2012 explicitly legalized rainwater harvesting. You can collect rainwater from rooftops and store it in a cistern under 360 gallons for outdoor non-potable use (landscape irrigation, livestock watering) without a permit or water-right approval. Larger systems, potable (drinking water) systems, and systems that store more than 360 gallons typically require a permit.

What you must do: Contact Mono County Environmental Health or Planning Division and ask: "What are Mono County's rules for rainwater harvesting systems, including cistern size, storage, and potable vs. non-potable use?" In the interim, assume that non-potable systems under 360 gallons (California baseline) are allowed, but confirm before installing anything larger or planning to use rainwater for drinking.

Wells and Water Systems: County Permits Required, but Standards Are State-Driven

Private wells outside municipal service districts require a permit from Mono County Environmental Health. California law mandates that the well be drilled by a licensed contractor, meet California Well Standards (casing depth, grouting, and construction quality), and produce water that passes drinking-quality testing. Mono County does not publish its own well-spacing or setback ordinances; it defers to state baseline standards and Lahontan Regional Water Quality Control Board requirements.

Practical sequence: 1. Contact Mono County Environmental Health with your parcel map and proposed well location. 2. They will tell you the required setbacks (typically 100 feet from septic systems, and further if the Lahontan Basin Plan specifies more). 3. You will hire a licensed well driller; they will submit the design and construction plan for Environmental Health approval. 4. After drilling, water testing is required; results must meet California drinking-water standards (primary contaminants, bacteria, etc.). 5. You will receive a well permit once testing passes.

Water rights are tied to the parcel in California. Before purchasing land, ask the seller about existing water rights, claims, or agreements. Mono County does not create water rights; you inherit what comes with the property.

Utilities and Disconnection from the Grid: Off-Grid Is Permitted; Municipal Tie-In Not Required

California state law now explicitly permits off-grid electricity. Mono County does not require connection to municipal utilities if you are outside a service district. However, the Building Division must approve your off-grid power system *before* installation.

Where municipal lines run within a certain distance, some California jurisdictions can require connection; I found no evidence that Mono County does this, but confirm with the Building Division if you are near an existing utility line.

Off-grid sequence: 1. Building Division pre-approves your power system design (solar, battery, etc.). 2. You install the system. 3. Building Division conducts a final inspection. 4. You receive a Certificate of Approval or similar sign-off.

No interconnection agreement with a utility company is needed for a standalone off-grid system. However, if you plan to add grid-tied solar (panels that can feed excess power back to the grid), you will need a different permit and interconnection agreement.

Who Administers What: The Practical Map

• Planning Division: Zoning verification, land use confirmation, General Plan review.
• Building Division: Off-grid power system approval, building permits, defensible space enforcement.
• Environmental Health: Well permits, septic system approval, greywater and rainwater standards (confirm), water-quality testing.
• Lahontan Regional Water Quality Control Board: Basin Plan standards, septic setbacks, well spacing (for parcels in the Lahontan region, which covers much of Mono County).

When you call a county department, be ready to ask about both county and state requirements, and ask for written confirmation if the answer affects your project cost or timeline.

Timeline and Sequencing Reality

A realistic off-grid project in Mono County involves:

1. Zoning and land-use check (1 week): Call Planning Division, confirm your zone and permitted uses. 2. Site assessment (2-4 weeks): Hire a septic designer or environmental consultant to perform a perc test, assess soil, and identify the septic and well locations. 3. Well and septic permits (4-8 weeks): Submit applications to Environmental Health; receive approval or revision requests. 4. Power system design and Building Division approval (2-6 weeks): Consult an engineer or installer, submit plans, receive Building approval. 5. Construction and inspection (8-16 weeks): Install septic, drill well, build the dwelling, install power system. 6. Final inspections and occupancy (1-2 weeks): Building Division, Environmental Health, and utility sign-offs.

Total timeline: 4-9 months from zoning check to occupancy, depending on site complexity and permit backlog. If your perc test fails or soil conditions are poor, add 2-4 months for engineered system design and re-approval.

What Remains Unconfirmed

• Greywater reuse standards at the county level
• Rainwater harvesting standards at the county level
• Tiny home approval pathways and how the county classifies them
• RV occupancy rules outside avalanche zones

For each of these, contact the relevant department directly. The gaps exist because either Mono County has not published clear rules, or those rules have changed since my research. Get written confirmation before committing to a design.