The age of housing stock gives an indication of supply, demand, local construction levels, and the overall quality of housing available.

Nine percent of Lancaster County's housing stock has been constructed since the 2010s. This is above the Pennsylvania rate of 5%, and slightly below the national rate of 10%. Lancaster's percentage is to the same as Chester (9%), above Berks (4%), York (6%) and Dauphin and Lebanon (both 7%), and below Cumberland (11%).

Nineteen percent of Lancaster County's housing stock was constructed before the 1940s. This is below the Pennsylvania average of 25%, but above the national average of 12%. Lancaster's percentage is below Berks (28%) and Lebanon (23%), similar to Dauphin (20%), and above York (18%), Chester (13%) and Cumberland (15%).

Compared to Lancaster County, the City of Lancaster has higher rates of older housing stock. Only 2% of the City's stock has been constructed since the 2010s and 52% was constructed before 1940.

The multiyear figures are from the Census Bureau's American Community Survey. The bureau combined 5 years of responses to the survey to provide estimates for smaller geographic areas and increase the precision of its estimates. However, because the information came from a survey, the samples responding to the survey were not always large enough to produce reliable results, especially in small geographic areas. CGR has noted on data tables the estimates with relatively large margins of error. Estimates with three asterisks have the largest margins, plus or minus 50% or more of the estimate. Two asterisks mean plus or minus 35%-50%, and one asterisk means plus or minus 20%-35%. For all estimates, the confidence level is 90%, meaning there is 90% probability the true value (if the whole population were surveyed) would be within the margin of error (or confidence interval). The survey provides data on characteristics of the population that used to be collected only during the decennial census. Data for this indicator are released annually in December.