# Data Dictionary - US Building Permits by County (Census BPS) - monthly authorized housing units, cleaned Parquet

**Units:** vary by `series` - read the per-row `unit` column (overall: mixed (units / buildings / USD)).  Times are UTC.

| column | type | description |
|---|---|---|
| `zone` | str | 5-digit county FIPS (state 2 + county 3), e.g. 04013 = Maricopa County, AZ |
| `ts` | timestamp (UTC) | 1st of the survey month |
| `series` | str | metric - structure class, e.g. 'Units authorized - 5+ units' |
| `value` | float | The metric's figure for that structure class (buildings / units / USD) |
| `unit` | str | buildings / units / USD |
| `res_min` | int | Native resolution (43200 = monthly) |

*Source: U.S. Census Bureau, Building Permits Survey.*