Off-Grid Park Model Tiny Home: What It Actually Takes
Off Grid Park Model Tiny Home: What It Actually Takes
If you are looking at land with no power pole, no well, and no septic in the ground, you are probably wondering whether a park model tiny home can skip all of that. It can, but "off grid" is not one switch. It is three separate systems (power, water, waste) that each replace a hookup the home would otherwise plug into, and each one brings its own equipment, cost, and permit. A conventional septic system alone runs about $5,449 to $8,957 installed in the Portland area, and that is usually the cheapest of the three to get right.
Where we stand on this: NW Tiny Homes sells, delivers, and customizes park model homes built by Cavco and Champion. We do not design, sell, or install off-grid power, water, or septic systems. Nearly every home we deliver goes in on standard RV hookups (shore power, a water inlet, a sewer connection, and a propane line), because that is what park models are built for and it is the simplest path for most buyers. We put this guide together because customers ask about off-grid living often enough that we would rather hand you an honest map than a shrug. The actual system design belongs with a licensed electrician, a well driller, a septic designer, and your county.
Power
Park models, including the Cavco and Champion homes we sell, are generally wired with 120V residential-style circuits throughout, not the 12V DC systems common in smaller travel trailers. That means an off-grid setup runs the whole home through an inverter sized for its full load, usually on a 24V or 48V battery bank. Your electrician confirms the specific model's wiring and load before anyone sizes a system. The three common paths:
- Grid power. Run a line to the pad. This is what most of our customers do, and in many rural spots it costs less than people expect. The utility gives you the number.
- Hybrid. Grid power with solar panels and a battery for backup or to cut the bill. You keep the reliability and add independence in steps.
- Full off grid. Solar, a battery bank, and a generator for the dark stretches. Complete off-grid kits run from roughly $3,600 to $8,500 for small starter setups to around $17,000 for mid-size kits, before installation and before the generator.
Winter is the variable people underestimate. Solar output around Portland and Seattle drops sharply in the darkest months, well under half of summer production, so a full off-grid design here needs a generator, a larger battery bank, or both to get through December and January.
Heat, Hot Water, and Cooking
Propane does the heavy lifting in almost every off-grid park model. Propane furnaces, water heaters, and ranges are common in park models and draw very little electricity, just enough for ignition and a blower fan, which keeps the battery bank small. Tank sizes to know:
- 100 lb cylinder: about 23 gallons usable. Fine for cooking, tight for heating a full winter.
- 250-gallon tank: about 200 gallons usable. Typical for a modest home running a furnace, water heater, and stove.
- 500-gallon tank: about 400 gallons usable. Supports heavier heating loads and fewer fills.
A mini-split works as a shoulder-season helper for heat or cooling, but its compressor and startup surge add real load to a small battery bank, so most off-grid setups keep it supplemental and let propane carry the winter. Wood stoves are rare in RV-titled homes because of clearance requirements, the roof penetration for the flue, and added weight. Talk to your insurer before assuming one is workable.
Water
- Drilled well. In Oregon, a typical well runs $28 to $65 per foot, with an average complete residential well around $8,400 at a typical depth of about 200 feet. Washington costs vary by county and depth; local drillers give real numbers.
- Rainwater catchment. Oregon State University Extension confirms that collecting rain off a roof into a tank or cistern does not require a water right in Oregon, as long as the water never touches soil before it reaches storage. A building permit is likely required for tanks over 5,000 gallons, and a plumbing permit if the water feeds indoor fixtures. Sizing rule of thumb: about 0.6 gallons per square foot of roof per inch of rain.
- Hauled water and a cistern. The common fallback where a well is not practical. You buy the tank once and pay per delivery.
Whatever the source, filtration and usually UV treatment are standard for any well, rainwater, or hauled water feeding indoor plumbing.
Wastewater
- Conventional septic. Still the most common answer. In the Portland area, installation runs about $5,449 to $8,957, with alternative (aerobic) systems for tight or poorly draining lots running $10,000 to $20,000. Oregon DEQ requires a site evaluation and soil test (the perc test) at $700 to $2,000 before a construction permit is issued.
- Composting toilet. The Nature's Head runs under $1,000 and the Separett Villa close to $1,400 (it uses a 17-watt fan for odor control). Both cut the blackwater side of the problem, but both still produce liquid that needs a disposal plan.
- Holding tank with pump-out. The simplest option for a home that is seasonal or may move again. No treatment on site, just a scheduled truck.
We would rather hand you an honest map than a shrug.
Greywater (sink and shower water) has its own rules in both states. Oregon regulates it through DEQ's graywater tiers, and Washington under WAC 246-274, which restricts surface application and requires a diversion valve back to the sewage system. Your county health department administers both and can add requirements on top.
Internet
Starlink Roam is the default answer for rural land: $55 a month for 100GB, $80 for 300GB, or $175 for unlimited data, with one-time hardware at $349 for the standard dish or $199 to $249 for the Mini. A cellular signal booster is a common add-on where there is some signal to work with.
Permits Still Apply
Going off grid does not take you out of the permitting process. Counties in Oregon and Washington generally still require a septic permit if you install one, a well permit for a drilled well, and placement approval for how and where the home sits on your land. These rules vary by county and by zone within a county, so confirm with your local planning and environmental health departments before assuming any configuration is allowed. Our Zoning and Permits guide is the starting point, and our placement disclaimer explains why we point you to the county rather than promising an answer ourselves. Site access and the pad itself matter too; our delivery page covers what we check before a home goes on the truck.
A Realistic Starting Budget
The sourced ranges above, laid out as line items. These are estimates you confirm with your own contractors, not a package price. They do not add up to one number because your mix of choices (grid, hybrid, or full off grid; well or catchment; septic or composting) changes which lines apply to you.
| System | Option | Estimated range |
|---|---|---|
| Power | Small off-grid solar and battery kit | $3,600 to $8,500 |
| Power | Mid-size off-grid kit | Around $17,000 |
| Water | Drilled well (Oregon, about 200 ft) | $28 to $65 per foot, about $8,400 average |
| Wastewater | Conventional septic (Portland area) | $5,449 to $8,957 |
| Wastewater | Alternative (aerobic) septic | $10,000 to $20,000 |
| Wastewater | DEQ site and perc evaluation | $700 to $2,000 |
| Wastewater | Composting toilet | Under $1,000 to about $1,400 |
| Internet | Starlink Roam hardware | $199 to $349 |
| Internet | Starlink Roam monthly plan | $55 to $175 per month |
Every one of these numbers moves with your site, your county, and the contractor you hire. Get each estimate in writing before you commit to land.
Start with the guides, then come see a home
Off-grid systems are an education topic before they are a shopping topic. Read the guides first, then walk through a home and see exactly what you would be replacing.
Read the Buyer's GuideSee the Zoning and Permits guide for what your county requires, or schedule a tour at our Portland lot (1110 NE Columbia Blvd, 503-455-4447) or our Snohomish lot (9813 Airport Way, 360-217-4214), both open Wednesday through Sunday, 11am to 6pm.
Sources
EnergySage: Off-Grid Solar: Costs, Process, and Best Products, 2026
This Old House: Guide to Off-Grid Solar System Costs, 2026
Oregon State University Extension: Rainwater Harvesting in Tanks or Cisterns: Oregon Regulations, EM 9448, December 2024
WellDrillingCosts.com: Oregon Well Drilling Cost, 2026
Angi: How Much Does It Cost To Install a Septic System in Portland, OR?, 2026
Tiny Project: The Best Composting Toilets For Tiny Houses
Ferrellgas: Understanding the Various Propane Tank Sizes, July 2025
Battle Born Batteries: What Size Inverter Do I Need for My RV?
SatelliteInternet.com: Starlink Roam Review, 2026
Oregon DEQ: Graywater, Water Quality Programs
Washington State Department of Health: Greywater Reuse
Cost figures are estimates you confirm with your own contractors and your county, not fixed prices. NW Tiny Homes does not design, sell, or install off-grid power, water, or septic systems. NW Tiny Homes is a park model RV dealer: we sell, deliver, and service homes built by Cavco and Champion.
