Milwaukee runs a heating season that starts with the lake and does not let go until late spring. Cream City brick duplexes, flats, and bungalows hold cold and ask the heater to answer for months. Lake-effect snow stacks on north slopes. East wind drives grit and damp into mortar. Basements are part of the house, not a bonus, and they take the melt. The call is about what quit during that long run.
Ice at the eaves is what months of attic heat do to a cold edge. The dam grows, then melt finds a ceiling. Original wood sash on the lake side whistles from October on and never gets a break. Boilers carry much of the old housing; forced air carries bungalows changed later. A condenser is a short summer guest. The machine that matters has been running since the leaves dropped.
Clay soil and hard rain on frozen ground put water in those basements. Floor drains, ejector pits, and downspouts that end at the wall decide the outcome. Alleys and tight side yards hide the lateral and the outdoor equipment. Mice come in when the heat starts and stay. Salt and a long plow season wreck the walk and the parkway edge. None of this clears up in a week.
Say duplex, flat, bungalow, or a larger brick walk-up before you name the symptom. Say whether the heat has been running without a break. Water at a top-floor ceiling during a thaw is often the roof. Water at the basement floor after rain on frozen ground is often grade or the drain. A cold radiator and a dead furnace are different sentences. Lead with the one you have.
Milwaukee will keep the heating season long and the lake wind blunt. Name the side of the house that faces the lake if that wall is the wet one. Pick the trade that matches what quit, and say how long it has already been running hard. Pick the trade and call.