Plumbing in Austin is the trade a hard freeze exposes. Houses built for heat run supplies through attics, exterior walls, and outdoor tankless units with little protection. Hose bibs stay charged. Irrigation lines sit above ground. The night the cold arrives, those paths freeze. The morning it releases, ceilings open up, garages flood, and more than one fitting lets go at once. That pattern is the city. A slab leak and a creek backup are different calls.
If you are in the thaw, shut the water off where finishes are getting worse and do not close the ceiling yet. Photograph the split and save the fitting. Note whether the line was in the attic, in an outside wall, or at a bib on the north side. A water heater in an unconditioned closet can split at the same time. Say so. If the stain appeared with the thaw and not with rain, start here.
Outside the freeze, limestone hard water packs heaters, valves, and aerators until fixtures dribble and tanks rumble. That is a daily Austin failure and it has nothing to do with the cold. Slab leaks do show up, especially where east-side clay moves, but they are the quiet kind: a warm stripe, a sound of water with fixtures off, a spot that never dries. West over rock, the dig and the repair change. Say which ground the house sits on if you know it.
Creek flooding surcharges floor drains and low showers when water rises fast and leaves. Stop using the fixtures if sewage is coming up, and do not treat that as a freeze break or a simple clog. Cast iron and roots from live oaks slow older laterals on their own schedule. Galvanized remnants in bungalows close down with corrosion. Name what you can see at the heater and under the sink so the visit matches the material.
Have the address and one description: thaw break, slab leak, scaled heater, or sewage after the creek rose. Say slab, pier and beam, attic runs, or an outdoor unit on the wall. Say if the water is already off. Ask the visit to find the failed pipe before the drywall is closed. Call the number on this page.