How the risk level is set
We look at two things. The first is the average January low where you live, taken from ten years of daily weather. The second is where the pipes run. Pipes in an attic, a crawl space or a garage lose heat faster than pipes in a heated inside wall, and pipes on an outside wall or an outdoor spigot are the most exposed.
Each one adds points. A low score reads as low risk. Higher scores read as moderate, high or severe.
What the result means
Dearborn has an average January low of 21°F, so the climate part of the score is high. The pipe location settles the rest. A line inside a heated wall scores lower than one that crosses a crawl space or a garage, and an outdoor spigot scores highest.
An average is a typical figure and not a forecast. A single cold night can be colder than the January average, so the steps in the result are worth doing once and leaving in place.
What helps before a freeze
Know where the main water shut-off valve is. Drain and disconnect garden hoses and cover outdoor spigots before the first freeze. Insulate pipes in unheated spaces. On a freezing night, a slight drip at a faucet and open cabinet doors on outside walls help. If you will be away, keep the heat on or have the plumbing drained. A plumber can look at any run you are unsure about.
Climate figures: Daymet daily data 2015 to 2024 for each place.