What do the site, hazards, services and responsible authorities allow us to conclude before design or purchase?
Define the proposed use and actual parcel, then assemble source-dated information on flooding, soils, slopes, water, wastewater, utilities and access. Use maps to identify questions and needed investigations. Obtain project-specific records and competent assessment before treating a design, listing or favorable map color as proof of suitability.
Evidence checked October 16, 2026 (America/Denver). Version 1.0. Desk review; no hands-on testing.
What this guide helps you do
For an early site-question and evidence file, with a Boulder County resource example. This guide does not approve construction, establish legal access or water rights, certify a parcel as safe, design foundations or replace a survey, local land-use review and geotechnical investigation.
Define the decision and the actual parcel
Record the intended household use, occupants’ access needs, approximate location and the parcel reference from authoritative records. Distinguish an existing home, remodel and new site because services and approval questions can differ. Gather existing plans, surveys, permits and service records where available and note what remains unverified. Contact the actual land-use/building authority about the proposed use and required investigations. A real-estate description, a nearby road or an appealing building sketch cannot by itself establish legal access, connection capacity or an approved location for the proposed structure.
Read flood information with its identity and date
FEMA’s flood-map explanation points to the Map Service Center and emphasizes that lower mapped risk does not mean no risk. Locate the correct area and retain the map identifier, effective date and relevant revisions rather than a cropped color alone. Ask the local floodplain official how current mapping and site information affect the proposed project. Consider drainage and access questions even when a selected footprint is outside a high-risk area. This review checked the explanation and gateway without running an address search, verifying a panel or measuring elevations. Source: FEMA flood-map navigator.
Use soil mapping to plan the right investigation
NRCS’s guide explains defining an area of interest and producing soil maps and limitations reports. Keep the selected boundary, map units, legend, report options and dates with the result. The current Web Soil Survey home page expressly distinguishes general planning from applications that need onsite investigation. A mapped unit is not a borehole or a parcel-specific foundation finding. Discuss the relevant uncertainties with a soil/geotechnical professional and the building or wastewater authority. No area of interest, soil sample, report or engineering suitability was tested in this review. Source: NRCS Web Soil Survey learning guide.
Separate landslide history from modeled susceptibility
USGS’s map explanation distinguishes an inventory of known events from a susceptibility model, with differing confidence, coverage and resolution. Its limitations include not explicitly accounting for long-runout, which matters to locations downslope from susceptible terrain. Read the explanation and original-source links before interpreting an apparently blank or favorable map area. Ask the relevant local/state geological and planning authorities which site assessment is needed. This guide did not query a parcel, inspect a slope or establish stability; maps help frame an investigation rather than replace it. Source: USGS landslide inventory and susceptibility navigator.
Verify services and recurring responsibilities
CSU Extension’s Boulder rural-property chapter supplies questions about water sources and permits, septic records, irrigation infrastructure, utilities and communications. Use these as questions, with actual supplier records and current authorities providing the answers. Ask about connection availability, capacity, cost, reliability, maintenance and access, and retain responses with dates. The chapter contains older legal and generalized energy statements; they are not adopted as current law or site-specific findings. Do not assume that a visible line, neighboring service, old test or historical water use confirms the proposed project’s rights or service. Source: CSU Boulder rural-property questions: water, septic and utilities.
Make an evidence file that supports a real decision
Organize the proposed use, parcel identity, source maps, records, authority responses, specialist findings, costs and unresolved questions in one file. Identify which conclusions are preliminary and which have project-specific support. Include climate, seasonal access and emergency-service questions for the actual locality rather than filling gaps with national averages. Keep the conditions and next review attached to any decision. A future owner or designer should be able to trace why a location was chosen and what still needs verification before excavation, construction or a change of use.
A pathway to practice
- Define parcel and use: People, needs, records, authority
- Screen hazards and conditions: Flood, soils, slopes, climate
- Verify services and assessment: Access, water, waste, competent help
- Keep the decision traceable: Costs, conditions, gaps, future custodian
Resources and their limitations
FEMA flood-map navigator
Use it for: Locate effective map information and the responsible local floodplain review route.
Access and cost: Public reference freely readable; equipment, parts, installation, transport and professional services may cost extra.
How to use it: Use the Map Service Center link for the actual area; retain the map identity, effective date and any relevant revisions, and discuss site-specific questions with the local floodplain official.
Evaluation and limits: Explanation and gateway checked; no address search, panel, elevation, map revision, parcel classification or permit was tested. Lower mapped risk is not an assurance of no flooding. Insurance topics are outside this guide.
Alternatives: Actual local floodplain administrator and current effective mapping; qualified survey/engineering assessment.
NRCS Web Soil Survey learning guide
Use it for: Define an area of interest and retain the applicable soil-map interpretations.
Access and cost: Public guide and Web Soil Survey gateway freely readable; specialist investigation and design may cost extra.
How to use it: Use the current Web Soil Survey home link, define the correct area and select the soil map and relevant limitations report. Keep map units, legend, report options and dates with the output.
Evaluation and limits: Existing guide-source ID reused and rechecked; current application home also captured. The home page visibly says Last Modified July 31, 2019, which is not the age of every dataset. No address/AOI, soil report, sample or engineering suitability was tested.
Alternatives: Local NRCS/soil scientist; actual geotechnical/site investigation; local building and wastewater authority.
Open NRCS Web Soil Survey learning guide
USGS landslide inventory and susceptibility navigator
Use it for: Separate mapped past events from modeled susceptibility and its limits.
Access and cost: Public reference freely readable; equipment, parts, installation, transport and professional services may cost extra.
How to use it: Read the inventory, susceptibility and limitation explanations before opening the map; follow original-source information and local hazard review for the actual site.
Evaluation and limits: Page dated February 3, 2025; gateway checked, not an address or map result. Inventory coverage/confidence vary, and the model does not explicitly account for long-runout. No parcel stability, slope or foundation was assessed.
Alternatives: State/local geological survey and planning authority; qualified geologist/geotechnical assessment.
Open USGS landslide inventory and susceptibility navigator
CSU Boulder rural-property questions: water, septic and utilities
Use it for: Ask for actual water, septic, power and communications records before deciding on a site.
Access and cost: Public reference freely readable; equipment, parts, installation, transport and professional services may cost extra.
How to use it: Use Questions to Ask About Water When Buying a Property and Utilities as a question list. Verify each answer with actual records, suppliers and current authorities.
Evaluation and limits: Chapter includes older legal/generalized energy statements; these are not adopted as current law or site-specific performance findings. No service capacity, connection cost, water right, mineral title, access right or property approval was verified.
Alternatives: Actual local planning/building authority, supplier and wastewater program; current DWR records and competent property review.
Open CSU Boulder rural-property questions: water, septic and utilities
Checklist
- Proposed use and actual parcel identified
- Current local land-use/building review route established
- Flood map identity, date and revisions retained
- Soil and slope information paired with investigation limits
- Services, access and recurring responsibilities verified from actual records
- Costs, conditions and unresolved questions kept in a handover file
Related guides
Water sources and household needs (SG-D07-S01); Rainwater, greywater and reuse (SG-D07-S04); Toilets, wastewater and sanitation (SG-D07-S06); Hazardous household materials (SG-D07-S08); Building design and space planning (SG-D08-S02); Construction methods and materials (SG-D08-S03); Owner-building and project management (SG-D08-S04); Finding primary sources (SG-D18-S02).
From the Whole Earth registry to current practice
Spring 1969 The Owner-Built Home (PDF page 24, printed page 22; entry WE69S-E045 and lesson WE69S-L003) asks readers to consider the site, space needs and preferences and read Site and Climate before design. This visually verified historical question organizes the modern assessment. The page’s old structural, material and plumbing details are not current specifications or approval.
Whole Earth Spring 1969 archive edition
Sources and review notes
No parcel, address-map query, site visit, soil/groundwater test, foundation, survey, access right, utility quote or permit was assessed. NRCS guide and current home gateway were checked; a visible website modification date is not every dataset’s date. The historical Owner-Built Home page supplies the site-first question, not modern structural or legal approval.
