Plumbing in St. Louis fails in clay laterals and in brick stacks when river storms dump more water than the line can take. A floor drain that returns sewage is the backup, not a slow sink. Roots at old joints and a belly in the lateral show up as a lower tub that burps when the washer runs. Ejector pits in garden units fail at the float, and the lid tells you. Say whether the sky just opened or the drain has been slow for months.
Galvanized stacks pinhole inside plaster and look like a storm stain until you see the bubble in dry weather too. Describe that difference. Main shutoffs on these buildings often spin without closing. If yours does, say so. Hose bibs still split in a freeze; the interior stop may be forgotten. Water heaters leak at the tank on a busy morning. Know gas or electric, and shut the supply if the floor is flooding. A disturbed flue belongs up front.
Downspouts that dump at a brick foundation become a basement flood that feels like a plumbing failure and starts as grade. Say if the water is clear and arrives with the rain, or if it is sewage. Those are different calls. A shared stack in a multi-family building backs up into the lowest fixture. That pattern matters. Catch basins and alley drains are part of the map. Say where the cleanout is.
Do not lead with a frozen-pipe story unless a sill cock or an exterior wall actually froze. This city's urgent water is the storm backup. A top-floor ceiling that wets only in wind-driven rain is the roof or the parapet. Mention it so the wrong trade does not open the wall. Radiator drips in older heat get mistaken for supply leaks. Look at the valve. Mineral crust is not a river event.
Lead with backup, a burst stack, no hot water, or sewage at the floor drain. Name the floor. St. Louis rain will test the lateral again. Call the number on this page.