If you can reach the supply shutoff safely, close it. Move people away from the affected area and do not enter water near electricity. Repairing the pipe and addressing the water damage are different tasks.
Stop only what you can reach safely
Know the shutoff location before an emergency if possible. During a leak, do not cross water to operate an electrical panel, unplug an appliance or search for a valve. If access is unsafe, stay clear and seek appropriate emergency or qualified professional help.
Call the right professional for the source
A licensed plumber may need to locate and repair the pipe failure. Do not turn the supply back on to recreate the leak. Keep the plumbing repair details because they help distinguish source control from the damage that has already spread.
Map the affected spaces without entering them
Note wet rooms, nearby cabinetry and ceilings below. Keep clear of sagging material. A spill that looks contained can have reached floor layers or wall edges. Safe photos and the approximate discovery time are useful, but do not delay asking for guidance to collect everything.
Plan extraction and drying
Once safe access and source control are addressed, assessment can guide water removal and drying. Wiping the floor does not establish that the building materials are dry. Keep related receipts and ask your carrier about policy reporting requirements.