Front Yard Sprinkler Pressure Drop—Leak vs. Restriction Diagnosis

4-zone system: 2 front zones low pressure (2 years worsening). Side/back fine. Supply fully open. Valve replaced—no change. No visible leaks. Capped heads test—no wet soil.

Leak vs. Restriction

Bad leak would show surface water. More likely: pipe restriction (crushed, root intrusion, debris) or valve not opening fully.

Flow Measurement Test

1. Run good zone, time water meter dial (0-10) for 1 minute = GPM
2. Run bad zone, same test
3. Example: Good = 20 GPM, Bad = 10 GPM → 50% restriction

Interpretation

• Low flow + good pressure at valve → pipe restriction
• Low flow + low pressure at valve → valve not opening fully

Measure at meter to quantify the problem.