(Please note that in certain situations,  what ,  when , and  where  can function as relative pronouns.) Relative pronouns introduce relative clauses, which are a type of dependent clause. Relative clauses modify a word, phrase, or idea in the main clause.
The 2014 Survey of Construction (SOC) from the Census Bureau shows that the average completion time of a single-family house is around 7 months, which usually includes around 25 days from authorization to start and another 6 months to finish the construction.
The length of time to get a house will vary. On average the family selection process takes 3-4 months and construction takes 6-8 months. Patuxent Habitat builds only in Calvert and St. Mary's counties at this time. So you would have to be willing to live in neighborhoods in those counties.