Sources checked
Describe the proposal precisely
Prepare the parcel address or identifier, house type, intended duration of occupancy and planned utility systems. Ask the local planning and building authorities to respond to that specific proposal. A general answer about tiny houses may not resolve your situation.
Ask about the use and the structure
Keep land-use permission separate from construction approval. Ask which authority handles each part, what documents are needed and whether any conditions apply. Request written references to the applicable requirements.
Investigate access and services
Ask about delivery access, legal access rights, water supply, wastewater options and electricity. Request site-specific assessments and quotes rather than assuming nearby services are available to the parcel.
Check wastewater early
If an existing septic system is involved, obtain its records and arrange an appropriate assessment. EPA provides a homebuyer guide to septic systems. For an undeveloped parcel, ask the responsible local authority and qualified installer how suitability and permission are established.
Decide with the whole project in view
Bring the purchase price, investigations, site preparation, transport and connection quotes together. Record unresolved issues and who can answer them. Treat ownership of the land and permission for your intended home as separate questions.
Keep a parcel due-diligence register
| Investigation | Evidence | Unresolved consequence |
|---|---|---|
| Use and dwelling category | Written response and applicable conditions | The intended home may not be permitted |
| Access and boundaries | Survey/title information and delivery assessment | Legal access or turning space may be inadequate |
| Water and wastewater | Records, site assessment and authority response | Connection or installation may be infeasible |
| Ground and drainage | Site-specific professional findings | Groundworks may materially change the project |
| Complete development cost | Current site, service and transport quotes | The land purchase may consume the build budget |
Give each issue an owner and a date. Where the transaction depends on investigations, obtain appropriate local advice about the agreement. Avoid interpreting a listing’s word unrestricted as a guarantee that every building, service or residential use is allowed. See our land-development and septic guides for the questions to resolve early.
Turn parcel research into a written decision record
Before a viewing, prepare a parcel sheet with the identifier, ownership information you have, the proposed home category and intended use. At the viewing, record questions about access, apparent wet areas, services, neighboring uses and the delivery route. Keep observations distinct from findings confirmed by an appropriate authority or professional. A dry afternoon does not establish year-round drainage.
| Issue | Evidence to request | Who to involve |
|---|---|---|
| Boundaries and legal access | Relevant records, easements and a suitable survey where needed | Local property professionals and authority |
| Intended use | Written response for this parcel and this home | Planning and building offices |
| Water and electricity | Availability, connection scope and an actual quote | Providers and qualified installers |
| Wastewater | Records or a parcel-specific assessment and approval route | Responsible authority and qualified specialist |
| Delivery and placement | Vehicle access, unloading method and supports | Mover, designer and site contractor |
Ask for the largest unknowns to be resolved before spending on cosmetic site work or an irrevocable home specification. A wastewater result, access restriction or service quote can change the feasible project. Include the investigation costs in the budget even if the parcel is ultimately rejected. Spending to establish that a site is unsuitable can prevent a much larger commitment.
Save the response, its date, the proposal it assessed and any conditions. If you change from a guest unit to a full-time dwelling, increase the number of homes or choose another structural category, return to the responsible offices with the revised proposal. A useful due-diligence record should make the remaining questions visible to anyone helping with the purchase.
Sources & further reading
Official guidance and original source material used for the factual points in this guide. Planning examples and worksheets are our own illustrations.
- Oregon Building Codes Division: current residential code adoption — Oregon only; includes the October 2026 transition dates.
- U.S. EPA: homebuyer guide to septic systems
Checked 8 October 2026. Location-specific rules, availability and product specifications can change. Suggest a correction.