Off-grid water starts with the source—not the filter.
A tiny house can use hauled water, a private well, rainwater or a combination. The right setup depends on local rules, water quality, refill access and how much water the household actually uses.
Choose the supply before sizing the tank.
Simple mechanically, but autonomy depends on storage volume, refill distance, delivery reliability and whether the tank can be protected from heat or freezing.
Can provide an on-site source, but private well owners are generally responsible for water safety. Testing, maintenance, pumping power and local well/septic rules all matter.
Useful in some climates and jurisdictions, but collected rainwater is not automatically safe to drink. Roof, gutter and storage materials can introduce germs or chemicals, and potable use requires appropriate testing and treatment.
Source → quality → storage → treatment → plumbing.
Do not start by buying a filter and assume it solves every source-water problem.
Well, delivered water, rainwater or utility connection.
Know which germs or chemicals actually need to be addressed.
Daily gallons and refill interval determine useful tank volume.
Treatment method should match the contaminants and intended use.
Clear-looking rainwater can still be unsafe.
CDC says rainwater can pick up germs and chemicals from the air, roof, gutters, piping and storage system. If it will be used for drinking, cooking or bathing, CDC recommends regular testing and treatment appropriate to the contaminants present.
CDC also recommends keeping rainwater physically separated from treated piped water so an unsafe source cannot contaminate the treated system.
Owning the well means owning the testing responsibility.
EPA notes that private domestic wells are not regulated by the federal Safe Drinking Water Act in the same way public systems are. CDC recommends testing well water at least annually for total coliform bacteria, nitrates, total dissolved solids and pH, with additional testing based on local risks and health-department guidance.
How many days will your water last?
Use your measured or planned daily household consumption, then leave a reserve instead of treating every gallon in the tank as available.
Open water autonomy calculator →
Water safety, plumbing, rainwater collection and well requirements can be regulated locally. This guide is planning information, not a potable-water-system design or public-health determination.