The first move is mechanical: close the main shutoff. Every gallon after that decision is a gallon that does not need drying, and the shutoff is the one tool every homeowner should be able to find in the dark. If water has reached outlets or appliances, cut power to those rooms at the breaker before wading in.
In Mission Viejo the first hour is a slab hour. Close the main shutoff at the street side meter or the house valve, then walk the floors barefoot: a warm patch marks a hot line leaking under the slab, and that patch, photographed with the meter reading beside it, is the evidence the repair and any claim will be built on. Do not run the dishwasher or the laundry to test anything. A quiet meter after shutoff confirms the leak is on the house side, which is the sentence the plumber needs first.
The second move is evidence: photographs of the failed line, the rooms, and the water's reach, taken before anything is moved or mopped. Insurers approve documented sudden losses; undocumented ones get argued. Note the time you found it and the time the water stopped.
The third move is the repair read: a split is a symptom with a cause (freeze, corrosion, pressure, age), and the repair visit should name the cause, because a patched effect with a live cause is next season's burst in a nearby section of the same run.
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