Standing Water After Sprinkler Installation: Leak or Drainage Issue?

Persistent puddles and a water-filled valve box five days after system winterization—with no rain—strongly indicate a leak, not residual moisture. The installer's claim that clay "leaching" or neighbor runoff causes this doesn't hold up.

Immediate Checks

1. Verify main shutoff valve: Ensure the irrigation main valve is fully closed. A partially open or leaking valve will slowly flood the zone.
2. Check water meter: With all indoor fixtures off, watch the meter's leak indicator (small triangle or dial). Movement means a leak in the irrigation or house supply.
3. Inspect valve box: Water in the box after 5 days with system off means either the main shutoff isn't sealing or a valve is weeping.
4. Consider main line damage: If the wet area aligns with the main line trench, the installer may have nicked the house supply line.

Questions for the Installer

• "Can you confirm the irrigation main shutoff is 100% closed and not weeping?"
• "Will you pressure-test the main line to verify no leaks?"
• "Was the house main line exposed or crossed during trenching?"

Don't accept "it'll dry up" as an answer. Standing water after winterization = active leak. Document with photos and demand repair under warranty.