Short answer
Shut off the main water valve first. In most Valley homes it's on the main line near the front hose bib or in the garage by the water heater or softener. Then turn off power to any wet area, move valuables, start removing water, photograph everything for insurance, and call a plumber.
1. Stop the water
Find the main shutoff. In Valley homes, look:
2. Make it safe
If water is near outlets, a panel or appliances, turn off those breakers, and don't stand in water to do it. If the water heater is involved, shut its gas or power.
3. Limit the damage
- Move furniture and electronics
- Mop and wet-vac standing water
- Run fans; open cabinets to dry them out
- Photograph and video everything before cleanup
4. Call for help
Call a plumber to repair the pipe. For wet drywall, carpet or cabinets, a water damage restoration company can dry the structure properly so mold doesn't follow.
When to call a plumber
- Water is still running after you've closed what you can.
- You can't find or turn the main shutoff.
- There's sewage involved.
What the plumber does: see slab leak repair & reroutes.
Common questions
Should I turn off the water heater after closing the main?
Yes, turn off gas or power to a tank that may drain. Heating an empty tank damages it.
Editorial note: this guide is general information for Phoenix-area homeowners, not a diagnosis. Conditions vary by home, so a licensed plumber should confirm the cause before any repair.