Montana Off-Grid: DIY Greywater Wetland (Salatin-Approved)
TL;DR: Off-grid households can build a vertical flow constructed wetland to treat 1,000L of greywater daily for irrigation.
- Engineer-led design ensures 90%+ BOD/COD reduction.
- Treated effluent is pathogen-free for irrigation.
- Cost-effective at $2,500 USD with a two-week build.
- Solar-powered pumps enable off-grid operation.
- Integrated with food forests for nutrient cycling.
Why it matters: Decentralized greywater treatment reduces water consumption, reclaims nutrients, and lessens ecological impact, especially for remote homesteads.
Do this next: Review the open-source blueprints for material specifications and construction details.
Recommended for: Off-grid homesteaders, permaculture practitioners, and engineers seeking robust greywater treatment solutions for non-potable reuse.
This engineer-led guide from the Permies.com forum, endorsed by Joel Salatin, offers open-source blueprints for vertical flow constructed wetlands treating household greywater on a Montana off-grid homestead. Beds measure 3m x 2m x 1.5m, layered with 30cm gravel (10-20mm), 50cm sand (0.5-2mm), and topped with Phragmites australis reeds at 4/m² for phytoremediation. Influent pipes dose intermittently via pump timers at 1L/m²/day, ensuring aerobic conditions for 90%+ BOD/COD reduction and pathogen die-off (E.coli <100 CFU/100mL effluent). Three-year monitoring data confirms pathogen-free output suitable for irrigation, with nitrate removal at 85% and no odor issues. System handles 1,000L/day from a 4-person household. Construction details: excavate to liner specs (EPDM geomembrane), fill in lifts with compaction tests, plant post-filling. Pump setup uses 12V solar-powered peristaltic pumps with float switches for surge control (max 50L/dose). Filtration pre-wetland includes 200-micron spin-down and biochar columns for surfactants. Performance metrics: influent BOD 300mg/L to effluent 20mg/L; TSS from 150 to 5mg/L. Practical tips address cold climates—insulate beds with straw bales, use greenhouse enclosures for year-round function. Failures analyzed: over-dosing caused anaerobia (fixed by timer calibration), reed die-back from salts (mitigated by diversity planting with Typha). Cost: $2,500 USD materials, 2-week build. Integration with permaculture: effluent to food forests, building topsoil via sludge accumulation (10cm/year harvested). This provides practitioners with tested specs for decentralized treatment, emphasizing low-tech reliability and regulatory compliance for non-potable reuse.