Public product contract

Methodology, coverage & freshness

Plat Num is a parcel-development screening tool for Whatcom County. It combines published source facts, reviewed rules, and explicit assumptions to make an early feasibility case inspectable. Results are a starting point for diligence, not a permit determination, professional opinion, or promise of project outcome.

Coverage now

What the screening model supports

Coverage is intentionally narrow. Scenario availability still depends on the parcel facts, resolved jurisdiction, source evidence, and applicable rules.

Jurisdictions

  • Bellingham
  • Blaine
  • Everson
  • Ferndale
  • Lynden
  • Nooksack
  • Sumas
  • Unincorporated Whatcom County

Parcels and property types

County assessor parcels are searchable across the supported geography, including vacant and improved property. Automated capacity and economics focus on residential land and residential development; an assessor use label alone does not establish that a program is allowed.

Development programs

Supported concepts include retaining the current improvement, accessory dwelling units, detached homes, duplexes, townhouses, apartments, short plats and subdivisions, with rent or sale exits where the scenario applies.

Unsupported or review-led cases

Commercial, industrial, and mixed-use underwriting is outside the automated economics. Tribal land, unresolved jurisdiction or zoning, complex overlays, title restrictions, easements, private covenants, unusual access, and project-specific utility questions can stop automation and require manual review.

Source families

What informs a result

No single source answers development feasibility. Plat Num keeps observed facts, reviewed rules, and model assumptions distinct so their roles remain visible.

Parcel and assessment

Whatcom County parcel geometry, identifiers, situs facts, assessed values, property characteristics, and assessor sales records.

Zoning and code

Published municipal and county code, zoning maps, and reviewed rules-as-data used to resolve dimensional and use constraints.

Geometry and buildings

Parcel boundaries, checked-in geographic masks, and multi-source building footprints used to estimate existing and buildable site conditions.

Critical areas

Official GIS screening layers for wetlands, streams, flood, shoreline, water resources, and related buffers where the source and rule contract supports them.

Permits

City of Bellingham project-level permit records plus Census Building Permits Survey jurisdiction totals for all seven cities and the unincorporated balance.

Listings and transactions

Source-specific listing snapshots, Whatcom assessor transfers, and validated multifamily sale details used as dated market evidence.

Market assumptions

Published rent, cap-rate, sale, and marketability assumptions with source observations, confidence labels, and publication versions.

Costs and fees

Versioned construction-cost assumptions and jurisdiction-specific fee assumptions, shown separately from project quotes and operator overrides.

Finance assumptions

Explicit loan-to-cost, rate, term, carry, and return-target inputs used for screening. They are model inputs, not lender commitments.

Freshness semantics

Four dates, four meanings

Collection, publication, and computation are separate lifecycle events. Showing only the most recent system timestamp can hide the true age of an upstream fact.

  1. Source observation or effective date

    When the upstream fact applied: for example, a code effective date, assessment year, sale date, listing observation, or permit reporting period.

  2. Retrieval or import date

    When Plat Num collected and validated the source. This records collection activity; it does not make an older upstream fact newer.

  3. Publication date

    When a validated dataset, reviewed rule, or approved assumption version became active for customer-facing analysis.

  4. Analysis computation date

    When the parcel result was calculated from the then-published inputs. A saved report keeps this timestamp so later refreshes are distinguishable.

Evidence and audit trail

How a result can be checked

Result-level citations

Applied rules and material source facts carry citations or source identity where the result surface supports them. Follow the citation and verify the current upstream text before acting.

Rule dates

Rules-as-data preserve jurisdiction, code citation, and effective or reviewed dates. A later code amendment can make an older saved analysis stale even when its math is unchanged.

Assumption provenance

Published market assumptions retain their evidence, observation periods, confidence, and version. A customer override is labeled separately from the published default.

Report audit trail

Saved reports retain the analysis computation time, model and disclaimer versions, parcel and scenario inputs, and the evidence available to the report at creation time.

Reading a result

A gap is not the same as a “no”

Infeasible
The available inputs produce a specific modeled constraint, such as an envelope, density, access, parking, or return threshold that the concept does not meet.
Insufficient data
A required input is absent or too weak to calculate the result responsibly. This is different from a negative feasibility finding.
Source conflict
Two relevant sources disagree and the product cannot resolve the difference safely. The conflicting facts should be reviewed before proceeding.
Stale data
A source has exceeded its freshness threshold. The last accepted observation may remain visible with its date, but should be rechecked.
Manual review
The issue needs a planner, engineer, surveyor, utility, title, or other project-specific determination outside the automated rules.
Out of coverage
The parcel, jurisdiction, use, program, or source family is outside the product contract described on this page.

Screening disclaimer

Known limits to carry into diligence

Use the analysis to find questions, compare concepts, and organize evidence. Confirm material facts with the source agency and the appropriate licensed or qualified professional.

Listing coverage

For-sale evidence uses dated Redfin snapshots where available; it is not a live MLS feed. A missing match does not establish that a property is off market, and any asking price should be checked at the source.

Permit coverage

Project-level permit points are currently Bellingham-only. Census BPS fills the countywide view with annual or year-to-date jurisdiction aggregates, not individual project records, and its release can lag the current month.

Critical-area screening

Mapped layers and modeled buffers flag possible constraints. They do not replace a wetland delineation, habitat assessment, flood determination, shoreline review, or agency interpretation.

Building footprints

Footprints come from multiple public and open sources with different vintages and coverage. A countywide authoritative polygon layer has not been confirmed, so missing, duplicated, shifted, or outdated structures require site verification.

Water and utility adequacy

Mapped water-resource overlays can affect the modeled envelope, but Plat Num does not confirm service availability, connection capacity, water rights, well yield, septic feasibility, or utility-provider approval.

Site and legal facts

The analysis does not replace a survey, title report, easement and covenant review, geotechnical study, access approval, project-specific fee quote, appraisal, construction bid, or lender quote.

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See the contract in context

The Getting Started guide is the current public help path. A direct support contact is not yet published; until it is, the guide remains the maintained route for product guidance.