What it is
The affordability exhibit that appears in most rate studies: median household income for the service area, the bill at representative usage, and the bill as a share of income, at whatever geography the study needs.
An affordability exhibit is a division that takes a minute. What takes the afternoon is deciding which census geographies make up a service area, and what to do where a boundary cuts a tract in half. That decision gets written down, so the exhibit can be defended when somebody asks.
What you hand us
Your service area boundary, and the bill at each usage level under the current and proposed schedules. If you do not have a boundary as data, say so early — that is often the longest part of the work.
What you get back
A table at tract, place or system level, the bill as a share of income at each, and a note recording how the boundary was matched to geography and what was done where it did not line up.
What it is built from
The Census Bureau’s published American Community Survey tables, pulled for the engagement. To be plain about it: household income is not part of this corpus and is not something we hold or archive. It is public, we pull it, and the exhibit says which table and which vintage it came from.
What it does not do
It does not tell you what is affordable. Affordability thresholds are contested, they differ by state and by program, and the exhibit reports a ratio rather than a verdict.
It does not survey anybody. It is published data joined to a boundary, which means it describes the area and not your customers.
It does not resolve a boundary we cannot get. Where a service area has no published boundary, we say the geography could not be established rather than approximating it with a city limit.