NORTHWEST HOUSING RESEARCH
The 1978 line.
Construction dates can help frame the questions to ask before disturbing an old painted surface. They do not tell us the age or composition of your cabinets.
21 GEOGRAPHIES · TWO DISTINCT METHODS
Ask the age question.
Keep the limits in view.
Compiled October 9, 2026 from the supplied research packs. These source records have not been independently re-queried for this compilation.
Unit: housing units (all tenures and structure types)
Source date: 2020–2024 ACS five-year estimates
Before 1978 count: Exact count not supplied
Denominator: 85,421 · published ACS estimate of all housing units
Interpolated estimate: all units built before 1970 plus 80% of the 1970–79 bin. Rounded reported share; not an exact count of homes built before 1978. No exact bin values are reproduced in this compilation, so numerator is null.
Open source dataset ↗ · Local planning guide →Unit: housing units (all tenures and structure types)
Source date: 2020–2024 ACS five-year estimates
Before 1978 count: Exact count not supplied
Denominator: 9,540 · published ACS estimate of all housing units
Interpolated estimate: all units built before 1970 plus 80% of the 1970–79 bin. Rounded reported share; not an exact count of homes built before 1978. No exact bin values are reproduced in this compilation, so numerator is null.
Open source dataset ↗ · Local planning guide →Unit: housing units (all tenures and structure types)
Source date: 2020–2024 ACS five-year estimates
Before 1978 count: Exact count not supplied
Denominator: 4,722 · published ACS estimate of all housing units
Interpolated estimate: all units built before 1970 plus 80% of the 1970–79 bin. Rounded reported share; not an exact count of homes built before 1978. No exact bin values are reproduced in this compilation, so numerator is null.
Open source dataset ↗ · Local planning guide →Unit: housing units (all tenures and structure types)
Source date: 2020–2024 ACS five-year estimates
Before 1978 count: Exact count not supplied
Denominator: 7,641 · published ACS estimate of all housing units
Interpolated estimate: all units built before 1970 plus 80% of the 1970–79 bin. Rounded reported share; not an exact count of homes built before 1978. No exact bin values are reproduced in this compilation, so numerator is null.
Open source dataset ↗ · Local planning guide →Unit: housing units (all tenures and structure types)
Source date: 2020–2024 ACS five-year estimates
Before 1978 count: Exact count not supplied
Denominator: 307,719 · published ACS estimate of all housing units
Interpolated estimate: all units built before 1970 plus 80% of the 1970–79 bin. Rounded reported share; not an exact count of homes built before 1978. No exact bin values are reproduced in this compilation, so numerator is null.
Open source dataset ↗ · Local planning guide →Unit: housing units (all tenures and structure types)
Source date: 2020–2024 ACS five-year estimates
Before 1978 count: Exact count not supplied
Denominator: 18,140 · published ACS estimate of all housing units
Interpolated estimate: all units built before 1970 plus 80% of the 1970–79 bin. Rounded reported share; not an exact count of homes built before 1978. No exact bin values are reproduced in this compilation, so numerator is null.
Open source dataset ↗ · Local planning guide →Unit: housing units (all tenures and structure types)
Source date: 2020–2024 ACS five-year estimates
Before 1978 count: Exact count not supplied
Denominator: 10,395 · published ACS estimate of all housing units
Interpolated estimate: all units built before 1970 plus 80% of the 1970–79 bin. Rounded reported share; not an exact count of homes built before 1978. No exact bin values are reproduced in this compilation, so numerator is null.
Open source dataset ↗ · Local planning guide →Unit: housing units (all tenures and structure types)
Source date: 2020–2024 ACS five-year estimates
Before 1978 count: Exact count not supplied
Denominator: Compatible count not supplied · not supplied in source pack
Interpolated estimate: all units built before 1970 plus 80% of the 1970–79 bin. Rounded reported share; not an exact count of homes built before 1978. No exact bin values are reproduced in this compilation, so numerator is null. The pack does not give an exact all-housing-unit total; owner units or occupied units must not be substituted.
Open source dataset ↗ · Local planning guide →Unit: housing units (all tenures and structure types)
Source date: 2020–2024 ACS five-year estimates
Before 1978 count: Exact count not supplied
Denominator: Compatible count not supplied · not supplied in source pack
Interpolated estimate: all units built before 1970 plus 80% of the 1970–79 bin. Rounded reported share; not an exact count of homes built before 1978. No exact bin values are reproduced in this compilation, so numerator is null. The pack does not give an exact all-housing-unit total; owner units or occupied units must not be substituted.
Open source dataset ↗ · Local planning guide →Unit: housing units (all tenures and structure types)
Source date: 2020–2024 ACS five-year estimates
Before 1978 count: Exact count not supplied
Denominator: 9,450 · published ACS estimate of all housing units
Interpolated estimate: all units built before 1970 plus 80% of the 1970–79 bin. Rounded reported share; not an exact count of homes built before 1978. No exact bin values are reproduced in this compilation, so numerator is null.
Open source dataset ↗ · Local planning guide →Unit: housing units (all tenures and structure types)
Source date: 2020–2024 ACS five-year estimates
Before 1978 count: Exact count not supplied
Denominator: 6,342 · published ACS estimate of all housing units
Interpolated estimate: all units built before 1970 plus 80% of the 1970–79 bin. Rounded reported share; not an exact count of homes built before 1978. No exact bin values are reproduced in this compilation, so numerator is null.
Open source dataset ↗ · Local planning guide →Unit: housing units (all tenures and structure types)
Source date: 2020–2024 ACS five-year estimates
Before 1978 count: Exact count not supplied
Denominator: 1,040 · published ACS estimate of all housing units
Interpolated estimate: all units built before 1970 plus 80% of the 1970–79 bin. Rounded reported share; not an exact count of homes built before 1978. No exact bin values are reproduced in this compilation, so numerator is null. Small-CDP margins of error are large; share MOE is not calculated. Do not treat small percentage differences as statistically established.
Open source dataset ↗ · Local planning guide →Unit: housing units (all tenures and structure types)
Source date: 2020–2024 ACS five-year estimates
Before 1978 count: Exact count not supplied
Denominator: 2,078 · published ACS estimate of all housing units
Interpolated estimate: all units built before 1970 plus 80% of the 1970–79 bin. Rounded reported share; not an exact count of homes built before 1978. No exact bin values are reproduced in this compilation, so numerator is null. Small-CDP margins of error are large; share MOE is not calculated. Do not treat small percentage differences as statistically established.
Open source dataset ↗ · Local planning guide →Unit: housing units (all tenures and structure types)
Source date: 2020–2024 ACS five-year estimates
Before 1978 count: Exact count not supplied
Denominator: 1,583 · published ACS estimate of all housing units
Interpolated estimate: all units built before 1970 plus 80% of the 1970–79 bin. Rounded reported share; not an exact count of homes built before 1978. No exact bin values are reproduced in this compilation, so numerator is null. The pack reports a total-unit margin of error of ±189; share MOE is not calculated.
Open source dataset ↗ · Local planning guide →Unit: housing units (all tenures and structure types)
Source date: 2020–2024 ACS five-year estimates
Before 1978 count: Exact count not supplied
Denominator: Compatible count not supplied · not supplied in source pack
Interpolated estimate: all units built before 1970 plus 80% of the 1970–79 bin. Rounded reported share; not an exact count of homes built before 1978. No exact bin values are reproduced in this compilation, so numerator is null. The pack does not give an exact all-housing-unit total; owner units or occupied units must not be substituted.
Open source dataset ↗ · Local planning guide →Unit: housing units (all tenures and structure types)
Source date: 2020–2024 ACS five-year estimates
Before 1978 count: Exact count not supplied
Denominator: Compatible count not supplied · not supplied in source pack
Interpolated estimate: all units built before 1970 plus 80% of the 1970–79 bin. Rounded reported share; not an exact count of homes built before 1978. No exact bin values are reproduced in this compilation, so numerator is null. The pack does not give an exact all-housing-unit total; owner units or occupied units must not be substituted.
Open source dataset ↗ · Local planning guide →Unit: housing units (all tenures and structure types)
Source date: 2020–2024 ACS five-year estimates
Before 1978 count: Exact count not supplied
Denominator: 14,651 · published ACS estimate of all housing units
Interpolated estimate: all units built before 1970 plus 80% of the 1970–79 bin. Rounded reported share; not an exact count of homes built before 1978. No exact bin values are reproduced in this compilation, so numerator is null.
Open source dataset ↗ · Local planning guide →Unit: housing units (all tenures and structure types)
Source date: 2020–2024 ACS five-year estimates
Before 1978 count: Exact count not supplied
Denominator: Compatible count not supplied · not supplied in source pack
Interpolated estimate: all units built before 1970 plus 80% of the 1970–79 bin. Rounded reported share; not an exact count of homes built before 1978. No exact bin values are reproduced in this compilation, so numerator is null. The pack does not give an exact all-housing-unit total; owner units or occupied units must not be substituted.
Open source dataset ↗ · Local planning guide →Unit: housing units (all tenures and structure types)
Source date: 2020–2024 ACS five-year estimates
Before 1978 count: Exact count not supplied
Denominator: Compatible count not supplied · not supplied in source pack
Interpolated estimate: all units built before 1970 plus 80% of the 1970–79 bin. Rounded reported share; not an exact count of homes built before 1978. No exact bin values are reproduced in this compilation, so numerator is null. The pack does not give an exact all-housing-unit total; owner units or occupied units must not be substituted.
Open source dataset ↗ · Local planning guide →Unit: housing units (all tenures and structure types)
Source date: 2020–2024 ACS five-year estimates
Before 1978 count: Exact count not supplied
Denominator: 9,859 · published ACS estimate of all housing units
Interpolated estimate: all units built before 1970 plus 80% of the 1970–79 bin. Rounded reported share; not an exact count of homes built before 1978. No exact bin values are reproduced in this compilation, so numerator is null.
Open source dataset ↗ · Local planning guide →Unit: housing units (all tenures and structure types)
Source date: 2020–2024 ACS five-year estimates
Before 1978 count: Exact count not supplied
Denominator: Compatible count not supplied · not supplied in source pack
Interpolated estimate: all units built before 1970 plus 80% of the 1970–79 bin. Rounded reported share; not an exact count of homes built before 1978. No exact bin values are reproduced in this compilation, so numerator is null. The pack does not give an exact all-housing-unit total; owner units or occupied units must not be substituted.
Open source dataset ↗ · Local planning guide →Two methods, two kinds of evidence
The ACS B25034 source has a 1970–1979 decade bin. The source research estimates pre-1978 units as all pre-1970 bins plus 80% of that bin. This assumes a uniform distribution within the decade and is not an exact 1978 split. Percentages are rounded; sample uncertainty and interpolation error remain. Recorded original construction year permits a direct less-than-1978 selection without interpolation. Exact here means an administrative record count, not independent verification of each building year. Records with missing/invalid years must be excluded from the ratio denominator. The Oregon sample is SFR taxlots; Clark samples use residential property/built-parcel records. Do not combine the two as one count of houses.
What missing numbers mean
Null denotes absent or incompatible evidence. Do not replace null with zero, multiply rounded shares by sample totals to invent numerators, or divide by raw lots when the percentage excludes missing years. Published ACS denominators are survey estimates, not exact census enumerations.
The place boundary matters
City limits, CDPs, mailing cities, ZIP/ZCTAs, school districts, associations and study circles differ. Brush Prairie and Hockinson are separate CDPs grouped on one service page. The 20 service-area packs produce 21 place geographies. No combined Brush Prairie/Hockinson percentage is supplied. Some underlying research uses intersecting polygons and some uses point/centroid assignment. Neighborhood tables can overlap. Never sum neighborhoods to create city counts or all 42 series rows to create a metro total.
What the age cannot tell you
Construction year does not measure lead content, lead exposure, cabinet material, cabinet condition or cabinet replacement date. A house built before 1978 needs an appropriate renovation assessment; this dataset cannot determine requirements or safety for an individual project. A recorded 1978 year is not a lead test.
Privacy and provenance
Aggregate place-level counts only. No addresses, owner names, parcel identifiers, coordinates, contact information or household-level records. Do not build an address lookup that stores addresses. Compiled from the dated October 9, 2026 area packs. A fresh Census Reporter request was attempted but failed through both the shell network and web tool. Source records have not been independently re-queried in this compilation.
Start with the right project questions.
Tell your contractor the home’s approximate construction year and any known cabinet replacement or remodeling history. Ask how the actual coated surfaces will be assessed before preparation. This dataset cannot determine whether lead is present or prescribe the requirements for a particular job.